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This section summarizes the new features and functionality of Oracle TimesTen In-Memory Database 11g Release 2 (11.2.2) that are documented in this guide, providing links into the guide for more information.
LOB support
TimesTen supports LOBs (large objects). This includes CLOBs (character LOBs), NCLOBs (national character LOBs), and BLOBs (binary LOBs).
For details of support in PL/SQL, refer to "Large objects (LOBs)".
Associative array binds
Associative arrays, formerly known as index-by tables or PL/SQL tables, are supported as IN, OUT, or IN OUT bind parameters in TimesTen PL/SQL, such as from an OCI, Pro*C/C++, or JDBC application. This enables arrays of data to be passed efficiently between an application and the database.
Use of PL/SQL statements in dynamic SQL
TimesTen supports the use of PL/SQL anonymous blocks and procedure or function calls, in addition to SQL statements, in an EXECUTE IMMEDIATE statement or DBMS_SQL procedure or function call.
Refer to "Dynamic SQL in PL/SQL (EXECUTE IMMEDIATE statement)".
The purpose of this chapter is to summarize PL/SQL language elements and features and compare their support in TimesTen to their support in Oracle. In the Oracle Database documentation, many of these features are covered in "PL/SQL Language Elements" in Oracle Database PL/SQL Language Reference.
Table 9-1 PL/SQL language element and feature support in TimesTen
| Feature name | Description | Supported? | Example/comment |
|---|---|---|---|
|
|
Recompiles a PL/SQL procedure, function, or package. |
          Y |
Syntax and semantics are the same as in Oracle Database. For information about these statements, see "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference. |
|
|
Changes session parameters dynamically. |
          Y |
In TimesTen you can use For more information on this statement in TimesTen, see "ALTER SESSION" in Oracle TimesTen In-Memory Database SQL Reference. |
|
Assignment statement |
Sets current value of a variable, parameter, or element. |
          Y | |
|
|
Marks a routine as autonomous. |
          N |
TimesTen does not support autonomous transactions. |
|
Block declaration |
Declares a block, the basic unit of a PL/SQL source program. |
          Y |
See "PL/SQL blocks". |
|
|
Select multiple rows. |
          Y |
This clause can be used with the |
|
|
Executes a routine from within SQL. |
          Y |
In TimesTen, use the |
|
|
Evaluates an expression, compares it against several values, and takes action according to the comparison that is true. |
          Y | |
|
|
Closes a cursor or cursor variable. |
          Y |
See Example 2-13, "Using a cursor to retrieve information about an employee" (among others). |
|
Collection definition |
Specifies a collection, which is an ordered group of elements that are all of the same type. |
          Y |
Examples include associative arrays (index-by tables or PL/SQL tables), nested tables, and varrays. TimesTen supports all three of these collection types in PL/SQL programs, but supports only associative arrays as bound parameters between PL/SQL and applications written in other languages (such as OCI or JDBC). |
|
Collection methods |
Built-in subprograms that operate on collections and are called using "dot" notation. |
          Y |
See "Collection Methods" in Oracle Database PL/SQL Language Reference. Examples include |
|
Comments |
Text included within your code for explanatory purposes. |
          Y |
Single-line and multi-line comments are supported. |
|
|
Ends the current transaction and makes permanent all changes performed in the transaction. |
          Y |
See "COMMIT" in Oracle TimesTen In-Memory Database SQL Reference. Important: |
|
Connection attributes |
Equivalent to initialization parameters in Oracle Database. |
          Y |
See "PL/SQL connection attributes". Also see "PL/SQL first connection attributes" and "PL/SQL general connection attributes" in Oracle TimesTen In-Memory Database Reference. |
|
Constant and variable declarations |
Specify constants and variables to be used in PL/SQL code, in the declarative part of any PL/SQL block, subprogram, or package. |
          Y | |
|
|
Exits the current iteration of a loop and transfers control to the next iteration. |
          Y |
See "CONTINUE statement". |
|
|
Creates a PL/SQL function. |
          Y |
See "PL/SQL procedures and functions". Also see "CREATE FUNCTION" in Oracle TimesTen In-Memory Database SQL Reference. You are not required to run |
|
|
Creates a schema object associated with an operating system shared library. |
          N |
|
|
|
These statements are used together to create a PL/SQL package definition and package body. |
          Y |
Syntax and semantics are the same as in Oracle Database. See "PL/SQL packages". Also see "CREATE PACKAGE" and "CREATE PACKAGE BODY" in Oracle TimesTen In-Memory Database SQL Reference. You are not required to run |
|
|
Creates a PL/SQL procedure. |
          Y |
See "PL/SQL procedures and functions". Also see "CREATE PROCEDURE" in Oracle TimesTen In-Memory Database SQL Reference. Note: You are not required to run |
|
|
Creates a user-defined object type or collection type. |
          N |
TimesTen does not support |
|
|
Returns the current date in the session time zone. |
          Y |
In TimesTen this returns the current date in UTC (universal time). TimesTen does not support local time zones. |
|
Cursor attributes |
Appended to the cursor or cursor variable to return useful information about the execution of a data manipulation statement. |
          Y |
Explicit cursors and cursor variables have four attributes: The implicit cursor (SQL) has additional attributes: See "Using the %ROWCOUNT and %NOTFOUND attributes" and "Using FORALL with SQL%BULK_ROWCOUNT". Also see "Named Cursor Attribute" in Oracle Database PL/SQL Language Reference. |
|
Cursor declaration |
Declares a cursor. To execute a multi-row query, TimesTen opens an unnamed work area that stores processing information. A cursor lets you name the work area, access the information, and process the rows individually. |
          Y | |
|
Cursor variables (REF CURSORs) |
Act as handles to cursors over SQL result sets. |
          Y |
TimesTen supports See "PL/SQL REF CURSORs". |
|
Database links (dblinks) |
A pointer that defines a one-way communication path from an Oracle Database server to another database server. |
          N |
TimesTen does not support database links. |
|
|
Deletes rows from a table. |
          Y |
See "DELETE" in Oracle TimesTen In-Memory Database SQL Reference. |
|
|
Removes a PL/SQL procedure, function, or package, as specified. |
          Y |
Syntax and semantics are the same as in Oracle Database. You can refer to information about these statements in "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference. |
|
Error reporting |
(This is self-explanatory.) |
          Y |
TimesTen applications report errors using Oracle Database error codes instead of TimesTen error codes. The error messages that accompany the error codes are either TimesTen error messages or Oracle Database error messages. |
|
|
Associates a user-defined exception with a TimesTen error number. |
          Y |
See "EXCEPTION_INIT Pragma" in Oracle Database PL/SQL Language Reference. |
|
Exception definition |
Specifies an exception, which is a runtime error or warning condition. Can be predefined or user-defined. |
          Y |
Predefined conditions are raised implicitly. User-defined exceptions are raised explicitly by the |
|
|
Builds and executes a dynamic SQL statement. |
          Y |
TimesTen supports this as Oracle Database does to execute a SQL DML or DDL statement, execute a PL/SQL anonymous block, or call a PL/SQL stored procedure or function. See "Dynamic SQL in PL/SQL (EXECUTE IMMEDIATE statement)". In TimesTen, the |
|
Executing PL/SQL from client applications |
(This is self-explanatory.) |
          Y |
TimesTen supports ODBC, OCI, Pro*C/C++, TTClasses (a set of TimesTen C++ classes), JDBC, and ODP.NET. |
|
Executing PL/SQL from SQL |
(This is self-explanatory.) |
          N |
In TimesTen, you cannot execute PL/SQL from a SQL statement (either static or dynamic). |
|
|
Exits a loop and transfers control to the end of the loop. |
          Y |
See Example 6-2, "Use ALTER SESSION to change attribute settings" (among others). |
|
Expression definition |
Specifies an expression, which is a combination of operands (variables, constants, literals, operators, and so on) and operators. The simplest expression is a single variable. |
          Y |
See "Expressions" in Oracle Database PL/SQL Language Reference. |
|
|
Retrieves rows of data from the result set of a multi-row query. |
          Y |
See Example 2-13, "Using a cursor to retrieve information about an employee" (among others). |
|
|
Bulk-binds input collections before sending them to the SQL engine. |
          Y | |
|
Function declaration and definition |
Specifies a subprogram or stored program that can be declared and defined in a PL/SQL block or package and returns a single value. |
          Y |
In TimesTen, a stored function or procedure can be executed in an anonymous block or through a Use the Also refer to the table entry below for "Procedure declaration and definition". |
|
|
Branches unconditionally to a statement label or block label. |
          Y |
See "GOTO Statement" in Oracle Database PL/SQL Language Reference. |
|
|
Executes or skips a sequence of statements depending on the value of the associated boolean expression. |
          Y | |
|
Initialization parameters |
Initial parameter settings for an Oracle Database. |
          n/a |
TimesTen connection attributes are equivalent. See that entry above. |
|
|
Specifies whether a subprogram call is to be inline. |
          Y |
See "INLINE Pragma" in Oracle Database PL/SQL Language Reference. |
|
|
Inserts one or more rows of data into a table. |
          Y |
See "Example using the INSERT statement". Also see "INSERT" in Oracle TimesTen In-Memory Database SQL Reference. |
|
Literal declaration |
Specifies a numeric, character string, or boolean value. |
          Y |
Examples: Numeric literal: 135 String literal: 'TimesTen' |
|
|
Locks database tables in a specified lock mode. |
          N |
TimesTen does not support the |
|
|
Executes a sequence of statements multiple times. Can be used, for example, in implementing a |
          Y |
See Example 2-8, "Using a WHILE loop". Also see "Basic LOOP Statement" in Oracle Database PL/SQL Language Reference. |
|
|
Allows you to select rows from one or more sources for update or insertion into a target table. |
          Y |
TimesTen SQL statement. See "MERGE" in Oracle TimesTen In-Memory Database SQL Reference. |
|
Native dynamic SQL execution |
Processes most dynamic SQL statements through the |
          Y |
See the |
|
Use of non-ASCII character sets in names of tables, columns, procedures, functions, and other database objects. |
          N |
This is not supported in TimesTen. | |
|
Use of quoted non-uppercase names of tables, columns, procedures, functions, and other database objects. |
          N |
This is not supported in TimesTen (such as create or replace procedure "MixedCase" as begin ... end; | |
|
|
This is a no-operation statement. Control is passed to the next statement without any action. |
          Y |
See "NULL Statement" in Oracle Database PL/SQL Language Reference. Also, one is used in Example 3-3, "Declaring a record type". |
|
Object type declaration |
Specifies a custom object type, which is created in SQL and stored in the database. |
          N |
TimesTen does not support object types at the database level. For example, |
|
|
Executes the query associated with a cursor. Allocates database resources to process the query, and identifies the result set. |
          Y |
See Example 2-13, "Using a cursor to retrieve information about an employee". |
|
|
Executes the |
          Y | |
|
Package declaration |
Specifies a package, which is a database object that groups logically related PL/SQL types, items, and subprograms. |
          Y |
Use SQL statements See "PL/SQL packages". Also see "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference for information about the |
|
Procedure declaration and definition |
Specifies a subprogram or stored program that can be declared and defined in a PL/SQL block or package and performs a specific action. |
          Y |
In TimesTen, a stored procedure or function can be executed in an anonymous block or through a Use the Also refer to the table entry above for "Function declaration and definition". |
|
|
Stops normal execution of a PL/SQL block or subprogram and transfers control to an exception handler. |
          Y | |
|
Record definition |
Defines a record, which is a composite variable that stores data values of different types (similar to a database row). |
          Y | |
|
|
Asserts that a subprogram (usually a function) in a package specification or object type specification does not read or write database tables or package variables. |
          N |
TimesTen ignores this. |
|
Result cache |
This is a mechanism for caching the results of PL/SQL functions in a shared global area (SGA) that is available to every session that runs your application. |
          N |
TimesTen does not support this. |
|
|
Immediately completes the execution of a subprogram and returns control to the invoker. Execution resumes with the statement following the subprogram call. |
          Y |
See "RETURN Statement" in Oracle Database PL/SQL Language Reference. |
|
|
Specifies the variables in which to store the values returned by the statement to which the clause belongs. |
          Y |
See "RETURNING INTO clause" and "Examples using RETURNING INTO". |
|
|
Undoes database changes made during the current transaction. |
          Y |
See "ROLLBACK" in Oracle TimesTen In-Memory Database SQL Reference. Important: |
|
|
Provides a record type that represents a row in a database table. |
          Y |
See Example 2-2, "Assigning values to variables with the assignment operator". |
|
|
Names and marks the current point in the processing of a transaction. |
          N |
TimesTen does not support savepoints. |
|
|
Retrieves values from one row of a table ( |
          Y |
See Example 2-3, "Using SELECT INTO to assign values to variables". Also see "Query Result Set Processing" in Oracle Database PL/SQL Language Reference. |
|
|
Indicates that package state is required only for the duration of one call to the server. |
          N |
TimesTen does not support the |
|
|
Begins a read-only or read and write transaction. |
          N |
TimesTen does not support the |
|
|
Returns a character string containing the phonetic representation of a |
          Y |
See "SOUNDEX" in Oracle TimesTen In-Memory Database SQL Reference. |
|
SQL cursor |
Either explicit or implicit, is used to handle the result set of a |
          Y | |
|
|
Returns number code of the most recent exception. |
          Y |
Given the same error condition, error codes returned by the built-in function This is also noted in "TimesTen error messages and SQL codes". |
|
|
Returns the error message associated with the error-number argument. |
          Y |
Given the same error condition, error messages returned by the built-in function This is also noted in "TimesTen error messages and SQL codes". |
|
Supplied packages |
These are PL/SQL packages supplied with the database. |
          Y |
TimesTen provides a subset of the Oracle Database PL/SQL supplied packages. |
|
System tables and views |
These are tables and views provided with the database for administrative purposes. |
          Y |
TimesTen supports a subset of the Oracle Database system tables and views. See "System Tables" in Oracle TimesTen In-Memory Database System Tables and Views Reference. |
|
Triggers |
These are procedures that are stored in the database and activated when specific conditions occur, such as adding a row to a table. |
          N |
TimesTen does not support triggers, but you can achieve similar functionality using XLA. See "XLA and TimesTen Event Management" in Oracle TimesTen In-Memory Database C Developer's Guide. |
|
Returns statistics about library cache performance and activity. |
          Y |
See "ttPLSQLMemoryStats" in Oracle TimesTen In-Memory Database Reference. Note: In Oracle Database, the | |
|
|
Lets you use the data type of a field, record, nested table, database column, or variable in your own declarations, rather than hardcoding the data type. Particularly useful when declaring variables, fields, and parameters that refer to database columns. |
          Y | |
|
|
Updates the values of one or more columns in all rows of a table or in rows that satisfy a search condition. |
          Y |
See "UPDATE" in Oracle TimesTen In-Memory Database SQL Reference. |
|
|
In Oracle Database, use this system view to return statistics about library cache performance and activity. |
          n/a |
In TimesTen, use the |
One of the advantages of PL/SQL in TimesTen is the ability to integrate PL/SQL procedural constructs with the flexible and powerful TimesTen SQL language.
This chapter surveys the main PL/SQL programming features described in "Overview of PL/SQL" in Oracle Database PL/SQL Language Reference. Working from simple examples, you will learn how to use PL/SQL in TimesTen. Unless otherwise noted, the examples have the same results in TimesTen as in Oracle.
See the end of the chapter for TimesTen-specific considerations. See "TimesTen PL/SQL components and operations" for an overview of how applications interact with TimesTen in general and PL/SQL in particular.
The following are the main topics of this chapter:
|
Note: Except where stated otherwise, the examples in this guide use the TimesTenttIsql utility. In order to display output in the examples, the setting SET SERVEROUTPUT ON is used. For more information on ttIsql, see "ttIsql" in Oracle TimesTen In-Memory Database Reference. |
The basic unit of a PL/SQL source program is the block, or anonymous block, which groups related declarations and statements. TimesTen supports PL/SQL blocks.
A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. Example 2-1 shows the basic structure of a PL/SQL block.
|
Note: If you use Oracle In-Memory Database Cache (IMDB Cache): A PL/SQL block cannot be passed through to Oracle. (Also see "TimesTen PL/SQL with IMDB Cache".) |
Example 2-1 PL/SQL block structure
DECLARE -- (optional)
-- Variables, cursors, user-defined exceptions
BEGIN -- (mandatory)
-- PL/SQL statements
EXCEPTION -- (optional)
-- Actions to perform when errors occur
END -- (mandatory)
You can define either anonymous or named blocks in your PL/SQL programs. This example creates an anonymous block that queries the employees table and returns the data in a PL/SQL variable:
Command> SET SERVEROUTPUT ON;
Command> DECLARE
> v_fname VARCHAR2 (20);
> BEGIN
> SELECT first_name
> INTO v_fname
> FROM employees
> WHERE employee_id = 100;
> DBMS_OUTPUT.PUT_LINE (v_fname);
> END;
> /
Steven
PL/SQL procedure successfully completed.
You can define variables and constants in PL/SQL and then use them in procedural statements and in SQL anywhere an expression can be used.
For example:
Command> DECLARE
> v_hiredate DATE;
> v_deptno NUMBER (2) NOT NULL := 10;
> v_location VARCHAR2 (13) := 'San Francisco';
> c_comm CONSTANT NUMBER := 1400;
You can use the %TYPE attribute to declare a variable according to either a TimesTen column definition or another declared variable. For example, use %TYPE to create variables emp_lname and min_balance:
Command> DECLARE
> emp_lname employees.last_name%TYPE;
> balance NUMBER (7,2);
> min_balance balance%TYPE:= 1000;
> BEGIN
> SELECT last_name INTO emp_lname FROM employees WHERE employee_id = 100;
> DBMS_OUTPUT.PUT_LINE (emp_lname);
> DBMS_OUTPUT.PUT_LINE (min_balance);
> END;
> /
King
1000
PL/SQL procedure successfully completed.
You can assign a value to a variable in the following ways.
With the assignment operator (:=) (Example 2-2)
By selecting or fetching values into it (Example 2-3 following)
By passing the variable as an OUT or IN OUT parameter to a subprogram (procedure or function) and then assigning the value inside the subprogram (Example 2-4 following)
|
Note: TheDBMS_OUTPUT package used in these examples is supplied with TimesTen. For information on this and other supplied packages, refer to Chapter 8, "TimesTen Supplied PL/SQL Packages". |
Example 2-2 Assigning values to variables with the assignment operator
Command> DECLARE -- Assign values in the declarative section
> wages NUMBER;
> hours_worked NUMBER := 40;
> hourly_salary NUMBER := 22.50;
> bonus NUMBER := 150;
> country VARCHAR2(128);
> counter NUMBER := 0;
> done BOOLEAN;
> valid_id BOOLEAN;
> emp_rec1 employees%ROWTYPE;
> emp_rec2 employees%ROWTYPE;
> TYPE commissions IS TABLE OF NUMBER INDEX BY PLS_INTEGER;
> comm_tab commissions;
> BEGIN -- Assign values in the executable section
> wages := (hours_worked * hourly_salary) + bonus;
> country := 'France';
> country := UPPER('Canada');
> done := (counter > 100);
> valid_id := TRUE;
> emp_rec1.first_name := 'Theresa';
> emp_rec1.last_name := 'Bellchuck';
> emp_rec1 := emp_rec2;
> comm_tab(5) := 20000 * 0.15;
> END;
> /
PL/SQL procedure successfully completed.
|
Note: This example uses records, which are composite data structures that have fields with different data types. You can use the%ROWTYPE attribute, as shown, to declare a record that represents a row in a table or a row from a query result set. Records are further discussed under "PL/SQL composite data types". |
Example 2-3 Using SELECT INTO to assign values to variables
Select 10% of an employee's salary into the bonus variable:
Command> DECLARE
> bonus NUMBER(8,2);
> emp_id NUMBER(6) := 100;
> BEGIN
> SELECT salary * 0.10 INTO bonus FROM employees
> WHERE employee_id = emp_id;
> DBMS_OUTPUT.PUT_LINE (bonus);
> END;
> /
2400
PL/SQL procedure successfully completed.
Example 2-4 Assigning values to variables as parameters of a subprogram
Declare the variable new_sal and then pass the variable as a parameter (sal) to procedure adjust_salary. Procedure adjust_salary computes the average salary for employees with job_id='ST_CLERK' and then updates sal. After the procedure is executed, the value of the variable is displayed to verify that the variable was correctly updated.
Command> DECLARE
> new_sal NUMBER(8,2);
> emp_id NUMBER(6) := 126;
> PROCEDURE adjust_salary (emp_id NUMBER, sal IN OUT NUMBER) IS
> emp_job VARCHAR2(10);
> avg_sal NUMBER(8,2);
> BEGIN
> SELECT job_id INTO emp_job FROM employees
> WHERE employee_id = emp_id;
> SELECT AVG(salary) INTO avg_sal FROM employees
> WHERE job_id = emp_job;
> DBMS_OUTPUT.PUT_LINE ('The average salary for ' || emp_job
> || ' employees: ' || TO_CHAR(avg_sal));
> sal := (sal + avg_sal)/2;
> DBMS_OUTPUT.PUT_LINE ('New salary is ' || sal);
> END;
> BEGIN
> SELECT AVG(salary) INTO new_sal FROM employees;
> DBMS_OUTPUT.PUT_LINE ('The average salary for all employees: '
> || TO_CHAR(new_sal));
> adjust_salary(emp_id, new_sal);
> DBMS_OUTPUT.PUT_LINE ('Salary should be same as new salary ' ||
> new_sal);
> END;
> /
The average salary for all employees: 6461.68
The average salary for ST_CLERK employees: 2785
New salary is 4623.34
Salary should be same as new salary 4623.34
PL/SQL procedure successfully completed.
|
Note: This example illustrates the ability to nest PL/SQL blocks within blocks. The outer anonymous block contains an enclosed procedure. ThisPROCEDURE statement is distinct from the CREATE PROCEDURE statement documented in "PL/SQL procedures and functions", which creates a subprogram that will remain stored in the user's schema. |
Most SQL functions are supported for calls directly from PL/SQL. In the first example that follows, the function RTRIM is used as a PL/SQL function in a PL/SQL assignment statement. In the second example, it is used as a SQL function in a static SQL statement.
Example 2-5 Using the RTRIM function from PL/SQL
Use the TimesTen PL/SQL RTRIM built-in function to remove the right-most "x" and "y" characters from the string. Note that RTRIM is used in a PL/SQL assignment statement.
Command> DECLARE p_var VARCHAR2(30);
> BEGIN
> p_var := RTRIM ('RTRIM Examplexxxyyyxyxy', 'xy');
> DBMS_OUTPUT.PUT_LINE (p_var);
> END;
> /
RTRIM Example
PL/SQL procedure successfully completed.
Example 2-6 Using the RTRIM function from SQL
Use the TimesTen SQL function RTRIM to remove the right-most "x" and "y" characters from the string. Note that RTRIM is used in a static SQL statement.
Command> DECLARE tt_var VARCHAR2 (30);
> BEGIN
> SELECT RTRIM ('RTRIM Examplexxxyyyxyxy', 'xy')
> INTO tt_var FROM DUAL;
> DBMS_OUTPUT.PUT_LINE (tt_var);
> END;
> /
RTRIM Example
PL/SQL procedure successfully completed.
You can refer to information about SQL functions in TimesTen under "Expressions" in Oracle TimesTen In-Memory Database SQL Reference. See "SQL Functions in PL/SQL Expressions" in Oracle Database PL/SQL Language Reference for information about support for SQL functions in PL/SQL.
Control structures are among the PL/SQL extensions to SQL. TimesTen supports the same control structures as Oracle Database.
The following control structures are discussed here:
The IF-THEN-ELSE and CASE constructs are examples of conditional control. In Example 2-7, the IF-THEN-ELSE construct is used to determine the salary raise of an employee based on the current salary. The CASE construct is also used to choose the course of action to take based on the job_id of the employee.
Example 2-7 Using the IF-THEN-ELSE and CASE constructs
Command> DECLARE
> jobid employees.job_id%TYPE;
> empid employees.employee_id%TYPE := 115;
> sal employees.salary%TYPE;
> sal_raise NUMBER(3,2);
> BEGIN
> SELECT job_id, salary INTO jobid, sal from employees
> WHERE employee_id = empid;
> CASE
> WHEN jobid = 'PU_CLERK' THEN
> IF sal < 3000 THEN sal_raise := .12;
> ELSE sal_raise := .09;
> END IF;
> WHEN jobid = 'SH_CLERK' THEN
> IF sal < 4000 THEN sal_raise := .11;
> ELSE sal_raise := .08;
> END IF;
> WHEN jobid = 'ST_CLERK' THEN
> IF sal < 3500 THEN sal_raise := .10;
> ELSE sal_raise := .07;
> END IF;
> ELSE
> BEGIN
> DBMS_OUTPUT.PUT_LINE('No raise for this job: ' || jobid);
> END;
> END CASE;
> DBMS_OUTPUT.PUT_LINE ('Original salary ' || sal);
> -- Update
> UPDATE employees SET salary = salary + salary * sal_raise
> WHERE employee_id = empid;
> END;
> /
Original salary 3100
PL/SQL procedure successfully completed.
An iterative control construct executes a sequence of statements repeatedly, as long as a specified condition is true. Loop constructs are used to perform iterative operations.
There are three loop types:
Basic loop
FOR loop
WHILE loop
The basic loop performs repetitive actions without overall conditions. The FOR loop performs iterative actions based on a count. The WHILE loops perform iterative actions based on a condition.
Example 2-8 Using a WHILE loop
Command> CREATE TABLE temp (tempid NUMBER(6),
> tempsal NUMBER(8,2),
> tempname VARCHAR2(25));
Command> DECLARE
> sal employees.salary%TYPE := 0;
> mgr_id employees.manager_id%TYPE;
> lname employees.last_name%TYPE;
> starting_empid employees.employee_id%TYPE := 120;
> BEGIN
> SELECT manager_id INTO mgr_id
> FROM employees
> WHERE employee_id = starting_empid;
> WHILE sal <= 15000 LOOP -- loop until sal > 15000
> SELECT salary, manager_id, last_name INTO sal, mgr_id, lname
> FROM employees WHERE employee_id = mgr_id;
> END LOOP;
> INSERT INTO temp VALUES (NULL, sal, lname); -- insert NULL for tempid
> COMMIT;
> EXCEPTION
> WHEN NO_DATA_FOUND THEN
> INSERT INTO temp VALUES (NULL, NULL, 'Not found'); -- insert NULLs
> COMMIT;
> END;
> /
PL/SQL procedure successfully completed.
Command> SELECT * FROM temp;
< <NULL>, 24000, King >
1 row found.
The CONTINUE statement enables you to transfer control within a loop back to a new iteration.
Example 2-9 Using the CONTINUE statement
In this example, the first v_total assignment is executed for each of the 10 iterations of the loop. The second v_total assignment is executed for the first five iterations of the loop. The CONTINUE statement transfers control within a loop back to a new iteration, so for the last five iterations of the loop, the second v_total assignment is not executed. The end v_total value is 70.
Command> DECLARE
> v_total SIMPLE_INTEGER := 0;
> BEGIN
> FOR i IN 1..10 LOOP
> v_total := v_total + i;
> DBMS_OUTPUT.PUT_LINE ('Total is : ' || v_total);
> CONTINUE WHEN i > 5;
> v_total := v_total + i;
> DBMS_OUTPUT.PUT_LINE ('Out of loop Total is: ' || v_total);
> END LOOP;
> END;
> /
Total is : 1
Out of loop Total is: 2
Total is : 4
Out of loop Total is: 6
Total is : 9
Out of loop Total is: 12
Total is : 16
Out of loop Total is: 20
Total is : 25
Out of loop Total is: 30
Total is : 36
Total is : 43
Total is : 51
Total is : 60
Total is : 70
PL/SQL procedure successfully completed.
TimesTen supports execution of PL/SQL from client applications using ODBC, OCI, Pro*C/C++, JDBC, or TimesTen TTClasses (for C++).
As noted earlier, a block is the basic unit of a PL/SQL source program. Anonymous blocks were also discussed earlier. By contrast, procedures and functions are PL/SQL blocks that have been defined with a specified name. See "PL/SQL procedures and functions" for how to define and create them.
In TimesTen, a PL/SQL procedure or function that is standalone (created with CREATE PROCEDURE or CREATE FUNCTION) or part of a package can be executed using an anonymous block or a CALL statement. (See "CALL" in Oracle TimesTen In-Memory Database SQL Reference for details about CALL syntax.)
Consider the following function:
create or replace function mytest return number is begin return 1; end;
In TimesTen, you can execute mytest in either of the following ways.
In an anonymous block:
Command> variable n number;
Command> begin
> :n := mytest();
> end;
> /
PL/SQL procedure successfully completed.
Command> print n;
N : 1
In a CALL statement:
Command> variable n number; Command> call mytest() into :n; Command> print n; N : 1
In Oracle Database, you could also execute mytest through a SQL statement, as follows. This execution mechanism is not supported in TimesTen.
In a SELECT statement:
SQL> select mytest from dual;
MYTEST
----------
1
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Note: A user's own procedure takes precedence over a TimesTen built-in procedure with the same name, but it is best to avoid such naming conflicts. |
This section covers the following topics for passing data between an application and PL/SQL:
Refer to "Bind Variables" in Oracle Database PL/SQL Language Reference for additional information.
You can use ":var" notation for bind variables to be passed between your application (such as a C or Java application) and PL/SQL. The term bind variable (or sometimes host variable) is used equivalently to how the term parameter has historically been used in TimesTen, and bind variables from an application would correspond to the parameters declared in a PL/SQL procedure or function specification.
Here is a simple example using ttIsql in to call a PL/SQL procedure that retrieves the name and salary of the employee corresponding to a specified employee ID. In this example, ttIsql essentially acts as the calling application, and the name and salary are output from PL/SQL:
Command> VARIABLE b_name VARCHAR2 (25)
Command> VARIABLE b_sal NUMBER
Command> BEGIN
> query_emp (171, :b_name, :b_sal);
> END;
> /
PL/SQL procedure successfully completed.
Command> PRINT b_name
B_NAME : Smith
Command> PRINT b_sal
B_SAL : 7400
See "Examples using input and output parameters and bind variables" for the complete example.
See "PL/SQL procedures and functions" for how to create and define procedures and functions.
See "Binding parameters and executing statements" in Oracle TimesTen In-Memory Database C Developer's Guide and "Preparing SQL statements and setting input parameters" in Oracle TimesTen In-Memory Database Java Developer's Guide for additional information and examples for those languages.
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Parameter modes define whether parameters declared in a PL/SQL subprogram (procedure or function) specification are used for input, output, or both. The three parameter modes are IN (the default), OUT, and IN OUT.
An IN parameter lets you pass a value to the subprogram being invoked. Inside the subprogram, an IN parameter acts like a constant and cannot be assigned a value. You can pass a constant, literal, initialized variable, or expression as an IN parameter.
An OUT parameter returns a value to the caller of a subprogram. Inside the subprogram, an OUT parameter acts like a variable. You can change its value and reference the value after assigning it.
An IN OUT parameter passes an initial value to a subprogram and returns an updated value to the caller. It can be assigned a value and its value can be read. Typically, an IN OUT parameter is a string buffer or numeric accumulator that is read inside the subprogram and then updated. The actual parameter that corresponds to an IN OUT formal parameter must be a variable, not a constant or an expression.
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Note: TimesTen supports the binding of associative arrays (but not varrays or nested tables) asIN, OUT, or IN OUT parameters. See "Using associative arrays from applications". |
See "Examples using input and output parameters and bind variables".
PL/SQL is tightly integrated with the TimesTen database through the SQL language. This section covers use of the following SQL features in PL/SQL.
From within PL/SQL, you can execute the following as static SQL:
DML statements: INSERT, UPDATE, DELETE, and MERGE
Queries: SELECT
Transaction control: COMMIT a €ÿnd ROLLBACK
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Notes:
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For information on these SQL statements, refer to "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference.
Example 2-10 shows how to execute a query. For additional examples using TimesTen SQL in PL/SQL, see Chapter 5, "Examples Using TimesTen SQL in PL/SQL".
Example 2-10 Retrieving data with SELECT...INTO
Use the SELECT... INTO statement to retrieve exactly one row of data. TimesTen returns an error for any query that returns no rows or multiple rows.
This example retrieves hire_date and salary for the employee with employee_id=100 from the employees table of the HR schema.
Command> run selectinto.sql DECLARE v_emp_hiredate employees.hire_date%TYPE; v_emp_salary employees.salary%TYPE; BEGIN SELECT hire_date, salary INTO v_emp_hiredate, v_emp_salary FROM employees WHERE employee_id = 100; DBMS_OUTPUT.PUT_LINE(v_emp_hiredate || ' ' || v_emp_salary); END; / 1987-06-17 24000 PL/SQL procedure successfully completed.
You can use native dynamic SQL, through the EXECUTE IMMEDIATE statement, to accomplish any of the following:
Execute a DML statement such as INSERT, UPDATE, or DELETE.
Execute a DDL statement such as CREATE or ALTER. For example, you can use ALTER SESSION to change a PL/SQL first connection attribute.
Execute a PL/SQL anonymous block.
Call a PL/SQL stored procedure or function.
Call a TimesTen built-in procedure. (See "Built-In Procedures" in Oracle TimesTen In-Memory Database Reference.)
One use case is if you do not know the full text of your SQL statement until execution time. For example, during compilation you may not know the name of the column to use in the WHERE clause of your SELECT statement. In such a situation, you can use the EXECUTE IMMEDIATE statement.
Another use case is for DDL, which cannot be executed in static SQL from within PL/SQL.
To call a TimesTen built-in procedure that returns a result set, create a record type and use EXECUTE IMMEDIATE with BULK COLLECT to fetch the results into an array.
Example 2-11 provides a set of brief examples of EXECUTE IMMEDIATE. For additional examples, see "Examples using EXECUTE IMMEDIATE".
For more information, see "EXECUTE IMMEDIATE Statement" in Oracle Database PL/SQL Language Reference.
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Notes:
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Example 2-11 Using EXECUTE IMMEDIATE to execute PL/SQL
This provides a set of examples using PL/SQL in EXECUTE IMMEDIATE statements. (The examples are independent of each other.)
Create a table and execute a DML statement on it within a PL/SQL block, specifying the input parameter through a USING clause. Then select the table to see the result.
Command> create table t(i int);
Command> declare
> i number := 1;
> begin
> execute immediate 'begin insert into t values(:j);end;' using i;
> end;
> /
PL/SQL procedure successfully completed.
Command> select * from t;
< 1 >
1 row found.
Create a PL/SQL procedure foo then execute it in a PL/SQL block, specifying the input parameter through a USING clause:
Command> create or replace procedure foo(message varchar2) is
> begin
> dbms_output.put_line(message);
> end;
> /
Procedure created.
Command> begin
> execute immediate 'begin foo(:b);end;' using 'hello';
> end;
> /
hello
PL/SQL procedure successfully completed.
Create a PL/SQL procedure myprint then execute it through a CALL statement, specifying the input parameter through a USING clause:
Command> declare
> a number := 1;
> begin
> execute immediate 'call myprint(:b)' using a;
> end;
> /
myprint procedure got number 1
PL/SQL procedure successfully completed.
Usage notes for dynamic SQL
Code that is executed through EXECUTE IMMEDIATE generally shares the same environment as the outer PL/SQL block, as in Oracle Database. In particular, be aware of the following. (These points apply to using DBMS_SQL as well as EXECUTE IMMEDIATE.)
SQL and PL/SQL executed through EXECUTE IMMEDIATE will run in the same transaction as the outer block.
Any exception raised during execution of an EXECUTE IMMEDIATE statement will be propagated to the outer block. Therefore, any errors on the error stack when the EXECUTE IMMEDIATE statement is executed will be visible inside the outer block. This is useful for procedures such as DBMS_UTILITY.FORMAT_ERROR_STACK.
Errors on the error stack prior to execution of a PL/SQL block in an EXECUTE IMMEDIATE statement are visible inside the block, for example by using DBMS_UTILITY.FORMAT_ERROR_STACK.
The execution environment in which an EXECUTE IMMEDIATE statement executes will be the same as for the outer block. PL/SQL and TimesTen parameters, REF CURSOR state, and package state from the EXECUTE IMMEDIATE statement are visible inside the outer block.
Bulk binding is a powerful feature used in the execution of SQL statements from PL/SQL to move large amounts of data between SQL and PL/SQL. (This is different from binding parameters from an application program to PL/SQL.) With bulk binding, you bind arrays of values in a single operation rather than using a loop to perform FETCH, INSERT, UPDATE, and DELETE operations multiple times. TimesTen supports bulk binding, which can result in significant performance improvement.
Use the FORALL statement to bulk-bind input collections before sending them to the SQL engine. Use BULK COLLECT to bring back batches of results from SQL. You can bulk-collect into any type of PL/SQL collection, such as a varray, nested table, or associative array (index-by table). For additional information on collections, refer to "Using collections in PL/SQL".
You can use the %BULK_EXCEPTIONS cursor attribute and the SAVE EXCEPTIONS clause with FORALL statements. SAVE EXCEPTIONS allows an UPDATE, INSERT, or DELETE statement to continue executing after it issues an exception (for example, a constraint error). Exceptions are collected into an array that you can examine using %BULK_EXCEPTIONS after the statement has executed. When you use SAVE EXCEPTIONS, if exceptions are encountered during the execution of the FORALL statement, then all rows in the collection are processed. When the statement finishes, an error is issued to indicate that at least one exception occurred. If you do not use SAVE EXCEPTIONS, then when an exception is issued during a FORALL statement, the statement returns the exception immediately and no other rows are processed.
Refer to "Using FORALL Statement and BULK COLLECT Clause Together" in Oracle Database PL/SQL Language Reference for more information on these features.
Example 2-12 shows basic use of bulk binding and the FORALL statement. For more information and examples on bulk binding, see "Examples using FORALL and BULK COLLECT".
Example 2-12 Using the FORALL statement
In the following example, the PL/SQL program increases the salary for employees with IDs 100, 102, 104, or 110. The FORALL statement bulk-binds the collection.
Command> CREATE OR REPLACE PROCEDURE raise_salary (p_percent NUMBER) IS
> TYPE numlist_type IS TABLE OF NUMBER
> INDEX BY BINARY_INTEGER;
> v_id numlist_type; -- collection
> BEGIN
> v_id(1) := 100; v_id(2) := 102; v_id (3) := 104; v_id (4) := 110;
> -- bulk-bind the associative array
> FORALL i IN v_id.FIRST .. v_id.LAST
> UPDATE employees
> SET salary = (1 + p_percent/100) * salary
> WHERE employee_id = v_id (i);
> END;
> /
Procedure created.
Find out salaries before executing the raise_salary procedure:
Command> SELECT salary FROM employees WHERE employee_id = 100 OR employee_id = 102 OR employee_id = 104 OR employee_id = 100; < 24000 > < 17000 > < 6000 > 3 rows found.
Execute the procedure and verify results as follows.
Command> EXECUTE raise_salary (10); PL/SQL procedure successfully completed. Command> SELECT salary FROM employees WHERE employee_id = 100 or employee_id = 102 OR employee_id = 104 OR employee_id = 100; < 26400 > < 18700 > < 6600 > 3 rows found.
You can use a RETURNING INTO clause, sometimes referred to as DML returning, with an INSERT, UPDATE, or DELETE statement to return specified columns or expressions, optionally including rowids, from rows that were affected by the action. This eliminates the need for a subsequent SELECT statement and separate round trip, in case, for example, you want to confirm what was affected or want the rowid after an insert or update.
A RETURNING INTO clause can be used with dynamic SQL (with EXECUTE IMMEDIATE) or static SQL.
Through the PL/SQL BULK COLLECT feature, the clause can return items from a single row into either a set of parameters or a record, or can return columns from multiple rows into a PL/SQL collection such as a varray, nested table, or associative array (index-by table). Parameters in the INTO part of the clause must be output only, not input/output. For information on collections, refer to "Using collections in PL/SQL". For BULK COLLECT, see "FORALL and BULK COLLECT operations" and "Examples using FORALL and BULK COLLECT".
SQL syntax and restrictions for the RETURNING INTO clause in TimesTen are documented as part of the "INSERT", "UPDATE", and "DELETE" documentation in Oracle TimesTen In-Memory Database SQL Reference.
Also see "Examples using RETURNING INTO".
Refer to "RETURNING INTO Clause" in Oracle Database PL/SQL Language Reference for additional information about DML returning.
When PL/SQL programs execute SQL statements, the SQL statements are processed by TimesTen in the same manner as when SQL is executed from applications written in other programming languages. All standard behaviors of TimesTen SQL apply. In an IMDB Cache environment, this includes the ability to use all cache features from PL/SQL. When PL/SQL accesses tables in cache groups, the normal rules for those tables apply. For example, issuing a SELECT statement against a cache instance in a dynamic cache group may cause the instance to be automatically loaded into TimesTen from Oracle Database.
In particular, be aware of the following points about this functionality.
When you use static SQL in PL/SQL, any tables accessed must exist in TimesTen or the PL/SQL will not compile successfully. In the following example, ABC must exist in TimesTen:
begin insert into abc values(1, 'Y'); end;
In an IMDB Cache environment, there is the capability to use the TimesTen passthrough facility to automatically route SQL statements from TimesTen to Oracle Database. (See "Setting a passthrough level" in Oracle In-Memory Database Cache User's Guide for details of the passthrough facility.)
With passthrough=1, a statement can be passed through to Oracle Database if any accessed table does not exist in TimesTen. In PL/SQL, however, the statement would have to be executed using dynamic SQL.
Updating the preceding example, the following TimesTen PL/SQL block could be used to access ABC in Oracle Database with passthrough=1:
begin execute immediate 'insert into abc values(1, 'Y')'; end;
In this case, TimesTen PL/SQL can compile the block because the SQL statement is not examined at compile time.
While PL/SQL can be executed in TimesTen, in the current release the TimesTen passthrough facility cannot be used to route PL/SQL blocks from TimesTen to Oracle Database. For example, when using IMDB Cache with passthrough=3, statements executed on a TimesTen connection will be routed to Oracle Database in most circumstances. In this scenario, you may not execute PL/SQL blocks from your application program, because TimesTen would attempt to forward them to Oracle Database, which is not supported. (In the passthrough=1 example, it is just the SQL statement being routed to Oracle, not the block as a whole.)
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Important: PL/SQL procedures and functions can use any of the following cache operations with either definer's rights or invoker's rights: loading or refreshing a cache group with commit everyn rows, DML on AWT cache groups, DML on non-propagated cache groups (user managed cache groups without PROPAGATE enabled), SELECT on cache group tables that do not invoke passthrough or dynamic load, or UNLOAD CACHE GROUP.
PL/SQL procedures or functions that use any of the following cache operations must use invoker's rights ( |
TimesTen supports LOBs (large objects). This includes CLOBs (character LOBs), NCLOBs (national character LOBs), and BLOBs (binary LOBs).
PL/SQL language features support LOBs in TimesTen as they do in Oracle Database, unless noted otherwise.
This section provides a brief overview of LOBs and discusses their use in PL/SQL, covering the following topics:
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Note: TimesTen does not support CLOBs if the database character set isTIMESTEN8. |
You can also refer to the following:
"LOB data types" in Oracle TimesTen In-Memory Database SQL Reference for additional information about LOBs in TimesTen
Oracle Database SecureFiles and Large Objects Developer's Guide for general information about programming with LOBs (but not specific to TimesTen functionality)
A LOB is a large binary object (BLOB) or character object (CLOB or NCLOB). In TimesTen, a BLOB can be up to 16 MB in size and a CLOB or NCLOB up to 4 MB. LOBs in TimesTen have essentially the same functionality as in Oracle Database, except as noted otherwise. (See "Differences between TimesTen LOBs and Oracle Database LOBs".)
LOBs may be either persistent or temporary. A persistent LOB exists in a LOB column in the database. A temporary LOB exists only within an application.
In PL/SQL, a LOB consists of a LOB locator and a LOB value. The locator is an opaque structure that acts as a handle to the value. When an application uses a LOB in an operation such as passing a LOB as a parameter, it is passing the locator, not the actual value.
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Important: LOB manipulations through APIs that use LOB locators result in usage of TimesTen temporary space. Any significant number of such manipulations may necessitate a size increase for the TimesTen temporary data partition. See "TempSize" in Oracle TimesTen In-Memory Database Reference. |
To update a LOB, your transaction must have an exclusive lock on the row containing the LOB. You can accomplish this by selecting the LOB with a SELECT ... FOR UPDATE statement. This results in a writable locator. With a simple SELECT statement, the locator is read-only. Read-only and writable locators behave as follows.
A read-only locator is read consistent, meaning that throughout its lifetime, it sees only the contents of the LOB as of the time it was selected. Note that this would include any uncommitted updates made to the LOB within the same transaction prior to when the LOB was selected.
A writable locator is updated with the latest data from the database each time a write is made through the locator. So each write is made to the most current data of the LOB, including updates that have been made through other locators.
The following example details behavior for two writable locators for the same LOB:
The LOB column contains "XY".
Select locator L1 for update.
Select locator L2 for update.
Write "Z" through L1 at offset 1.
Read through locator L1. This would return "ZY".
Read through locator L2. This would return "XY", because L2 remains read-consistent until it is used for a write.
Write "W" through L2 at offset 2.
Read through locator L2. This would return "ZW". Prior to the write in the preceding step, the locator was updated with the latest data ("ZY").
A PL/SQL block can create a temporary LOB explicitly, for it own use. In TimesTen, the lifetime of such a LOB does not extend past the end of the transaction in which it is created (as is the case with the lifetime of any LOB locator in TimesTen).
A temporary LOB may also be created implicitly by TimesTen. For example, if a SELECT statement selects a LOB concatenated with an additional string of characters, TimesTen will implicitly create a temporary LOB to contain the concatenated data. Note that a temporary LOB is a server-side object. TimesTen has no concept of client-side LOBs.
Temporary LOBs are stored in the TimesTen temporary data partition.
See "CREATETEMPORARY procedures" in Oracle TimesTen In-Memory Database PL/SQL Packages Reference for how to create temporary LOBs.
Be aware of the following:
A key difference between the TimesTen LOB implementation and the Oracle Database implementation is that in TimesTen, LOB locators do not remain valid past the end of the transaction. All LOB locators are invalidated after a commit or rollback, whether explicit or implicit. This includes after any DDL statement if TimesTen DDLCommitBehavior is set to 0 (the default), for Oracle Database behavior, which is always the case for PL/SQL users.
TimesTen does not support BFILEs, SecureFiles, array reads and writes for LOBs, or callback functions for LOBs.
In TimesTen, the DBMS_LOB FRAGMENT procedures are not supported, so you can write data into the middle of a LOB only by overwriting previous data. There is no functionality to insert data into the middle of a LOB and move previous data, beginning at that point, higher in the LOB correspondingly. Similarly, in TimesTen you can delete data from the middle of a LOB only by overwriting previous data with zeros or null data. There is no functionality to remove data from the middle of a LOB and move previous data, beginning at that point, lower in the LOB correspondingly. In either case in TimesTen, the size of the LOB does not change, except in the circumstance where from the specified offset there is less space available in the LOB than there is data to write. (In Oracle Database there is functionality for either mode, either overwriting and not changing the size of the LOB, or inserting or deleting and changing the size of the LOB.)
TimesTen does not support binding arrays of LOBs.
TimesTen does not support batch processing of LOBs.
Relevant to BLOBs, there are differences in the usage of hexadecimal literals in TimesTen. See the description of HexadecimalLiteral in "Constants" in Oracle TimesTen In-Memory Database SQL Reference.
The following shows basic use of a CLOB. Assume a table defined and populated as follows, with a BLOB column (not used here) and a CLOB column:
Command> create table t1 (a int, b blob, c clob); Command> insert into t1(a,b,c) values(1, 0x123451234554321, 'abcde'); 1 row inserted. Command> commit;
Select a CLOB from the table and display it:
Command> declare
> myclob clob;
> begin
> select c into myclob from t1 where a=1;
> dbms_output.put_line('CLOB selected from table t1 is: ' || myclob);
> end;
> /
CLOB selected from table t1 is: abcde
PL/SQL procedure successfully completed.
The following tries to display the temporary CLOB again after a commit statement has ended the transaction, showing that the LOB locator becomes invalid from that point:
Command> declare
> myclob clob;
> begin
> select c into myclob from t1 where a=1;
> dbms_output.put_line('CLOB selected from table t1 is: ' || myclob);
> commit;
> dbms_output.put_line('CLOB after end of transaction is: ' || myclob);
> end;
> /
1806: invalid LOB locator specified
8507: ORA-06512: at line 8
CLOB selected from table t1 is: abcde
The command failed.
TimesTen supports subprograms of the DBMS_LOB package for manipulation of LOB data.
See "DBMS_LOB" in this document for a list and descriptions of these subprograms. See "DBMS_LOB" in Oracle TimesTen In-Memory Database PL/SQL Packages Reference for further information.
Passthrough LOBs, which are LOBs in Oracle Database accessed through TimesTen, are exposed as TimesTen LOBs and are supported by TimesTen in much the same way that any TimesTen LOB is supported, but note the following:
TimesTen LOB size limitations do not apply to storage of passthrough LOBs, but do apply to binding. Also, if a passthrough LOB is copied to a TimesTen LOB, such as through DBMS_LOB.COPY, the size limit applies to the copy.
An attempt to copy a passthrough LOB to a TimesTen LOB when the passthrough LOB is larger than the TimesTen LOB size limit will result in an error.
As with TimesTen local LOBs, a locator for a passthrough LOB does not remain valid past the end of the transaction.
See "DBMS_LOB" in this document for information about DBMS_LOB support for passthrough LOBs.
A cursor, either explicit or implicit, is used to handle the result set of a SELECT statement. As a programmer, you can declare an explicit cursor to manage queries that return multiple rows of data. PL/SQL declares and opens an implicit cursor for any SELECT statement that is not associated with an explicit cursor.
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Important: Be aware that in TimesTen, any operation that ends your transaction closes all cursors associated with the connection. This includes anyCOMMIT or ROLLBACK statement. This also includes any DDL statement executed when PL/SQL is enabled, because the DDLCommitBehavior connection must be set to 0 (Oracle Database behavior) if PL/SQL is enabled. This results in autocommits of DDL statements. See "Differences in TimesTen: transaction behavior" for additional information. |
Example 2-13 shows basic use of a cursor. See "Examples using cursors" for additional information and examples. Also see "PL/SQL REF CURSORs".
Example 2-13 Using a cursor to retrieve information about an employee
Declare a cursor c1 to retrieve the last name, salary, hire date, and job class for the employee whose employee ID is 120.
Command> DECLARE
> CURSOR c1 IS
> SELECT last_name, salary, hire_date, job_id FROM employees
> WHERE employee_id = 120;
> --declare record variable that represents a row
> --fetched from the employees table
> employee_rec c1%ROWTYPE;
> BEGIN
> -- open the explicit cursor
> -- and use it to fetch data into employee_rec
> OPEN c1;
> FETCH c1 INTO employee_rec;
> DBMS_OUTPUT.PUT_LINE('Employee name: ' || employee_rec.last_name);
> CLOSE c1;
> END;
> /
Employee name: Weiss
PL/SQL procedure successfully completed.
Procedures and functions are PL/SQL blocks that have been defined with a specified name.
Standalone subprograms (stored procedures or functions) are created at the database level with the CREATE PROCEDURE or CREATE FUNCTION statement.
Optionally use CREATE OR REPLACE PROCEDURE or CREATE OR REPLACE FUNCTION if you want the subprogram to be replaced if it already exists.
Use ALTER PROCEDURE or ALTER FUNCTION to explicitly compile a procedure or function or modify the compilation options. (To recompile a procedure or function that is part of a package, recompile the package using the ALTER PACKAGE statement.)
In TimesTen, syntax for CREATE PROCEDURE and CREATE FUNCTION is a subset of what is supported in Oracle Database. For information on these statements and the ALTER PROCEDURE and ALTER FUNCTION statements in TimesTen, see "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference.
Also see "How to execute PL/SQL procedures and functions".
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Notes:
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Example 2-14 Create and execute a procedure with OUT parameters
This example creates a procedure that uses OUT parameters, executes the procedure in an anonymous block, then displays the OUT values. The procedure takes an employee ID as input then outputs the salary and job ID for the employee.
Command> CREATE OR REPLACE PROCEDURE get_employee
> (p_empid in employees.employee_id%TYPE,
> p_sal OUT employees.salary%TYPE,
> p_job OUT employees.job_id%TYPE) IS
> BEGIN
> SELECT salary,job_id
> INTO p_sal, p_job
> FROM employees
> WHERE employee_id = p_empid;
> END;
> /
Procedure created.
Command> VARIABLE v_salary NUMBER;
Command> VARIABLE v_job VARCHAR2(15);
Command> BEGIN
> GET_EMPLOYEE (120, :v_salary, :v_job);
> END;
> /
PL/SQL procedure successfully completed.
Command> PRINT
V_SALARY : 8000
V_JOB : ST_MAN
Command> SELECT salary, job_id FROM employees WHERE employee_id = 120;
< 8000, ST_MAN >
1 row found.
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Note: Instead of using the anonymous block shown in the preceding example, you could use aCALL statement:
Command> CALL GET_EMPLOYEE(120, :v_salary, :v_job); |
Example 2-15 Create and call a function
This example creates a function that returns the salary of the employee whose employee ID is specified as input, then calls the function and displays the result that was returned.
Command> CREATE OR REPLACE FUNCTION get_sal
> (p_id employees.employee_id%TYPE) RETURN NUMBER IS
> v_sal employees.salary%TYPE := 0;
> BEGIN
> SELECT salary INTO v_sal FROM employees
> WHERE employee_id = p_id;
> RETURN v_sal;
> END get_sal;
> /
Function created.
Command> variable n number;
Command> call get_sal(100) into :n;
Command> print n;
N : 24000
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Note: Instead of using theCALL statement shown in the preceding example, you could use an anonymous block:
Command> begin
> :n := get_sal(100);
> end;
> /
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TimesTen supports private and public synonyms (aliases) for database objects, including PL/SQL procedures, functions, and packages. Synonyms are often used to mask object names and object owners or to simplify SQL statements.
Create a private synonym for procedure foo in your schema as follows:
CREATE SYNONYM synfoo FOR foo;
Create a public synonym as follows:
CREATE PUBLIC SYNONYM pubfoo FOR foo;
A private synonym exists in the schema of a specific user and shares the same namespace as database objects such as tables, views, and sequences. A private synonym cannot have the same name as a table or other object in the same schema.
A public synonym does not belong to any particular schema, is accessible to all users, and can have the same name as any private object.
To use a synonym you must have appropriate privileges to access the underlying object. For required privileges to create or drop a synonym, see "Required privileges for PL/SQL statements and operations".
For general information about synonyms, see "Understanding synonyms" in Oracle TimesTen In-Memory Database Operations Guide. For information about the CREATE SYNONYM and DROP SYNONYM statements, see "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference.
Example 2-16 Use a synonym for a procedure
In the following example, USER1 creates a procedure in his schema and creates a public synonym for it. Then USER2 executes the procedure through the public synonym. Assume the following:
USER1 has been granted CREATE SESSION, CREATE PROCEDURE, and CREATE PUBLIC SYNONYM privileges.
USER2 has been granted CREATE SESSION and EXECUTE ANY PROCEDURE privileges.
Both users have connected to the database.
USER2 employs the SET SERVEROUTPUT ON setting.
USER1:
Command> create or replace procedure test is
> begin
> dbms_output.put_line('Running the test');
> end;
> /
Procedure created.
Command> create public synonym pubtest for test;
Synonym created.
USER2:
Command> begin
> pubtest;
> end;
> /
Running the test
PL/SQL procedure successfully completed.
This section discusses how to create and use PL/SQL packages.
For information about PL/SQL packages provided with TimesTen, refer to Chapter 8, "TimesTen Supplied PL/SQL Packages."
A package is a database object that groups logically related PL/SQL types, variables, and subprograms. You specify the package and then define its body in separate steps.
The package specification is the interface to the package, declaring the public types, variables, constants, exceptions, cursors, and subprograms that are visible outside the immediate scope of the package. The body defines the objects declared in the specification, as well as queries for the cursors, code for the subprograms, and private objects that are not visible to applications outside the package.
TimesTen stores the package specification separately from the package body in the database. Other schema objects that call or reference public program objects depend only on the package specification, not on the package body.
|
Note: The syntax for creating packages and package bodies is the same as in Oracle Database; however, while Oracle documentation mentions that you must run a script namedDBMSSTDX.SQL, this does not apply to TimesTen. |
To create packages and store them permanently in the database, use the CREATE PACKAGE and CREATE PACKAGE BODY statements.
To create a new package, do the following:
Create the package specification with the CREATE PACKAGE statement.
You can declare program objects in the package specification. Such objects are referred to as public objects and can be referenced outside the package, and by other objects in the package.
Optionally use CREATE OR REPLACE PACKAGE if you want the package specification to be replaced if it already exists.
Create the package body with the CREATE PACKAGE BODY (or CREATE OR REPLACE PACKAGE BODY) statement.
You can declare and define program objects in the package body.
You must define public objects declared in the package specification.
You can declare and define additional package objects, referred to as private objects. Private objects are declared in the package body rather than in the package specification, so they can be referenced only by other objects in the package. They cannot be referenced outside the package.
Use ALTER PACKAGE to explicitly compile the member procedures and functions of a package or modify the compilation options.
For more information on the CREATE PACKAGE, CREATE PACKAGE BODY, and ALTER PACKAGE statements, see "SQL Statements" in Oracle TimesTen In-Memory Database SQL Reference.
|
Notes:
|
Example 2-17 Create and use a package
Consider the case where you want to add a row to the employees tables when you hire a new employee and delete a row from the employees table when an employee leaves your company. The following example creates two procedures to accomplish these tasks and bundles the procedures in a package. The package also contains a function to return the count of employees with a salary greater than that of a specific employee. The example then executes the function and procedures and verifies the results.
Command> CREATE OR REPLACE PACKAGE emp_actions AS
> PROCEDURE hire_employee (employee_id NUMBER,
> last_name VARCHAR2,
> first_name VARCHAR2,
> email VARCHAR2,
> phone_number VARCHAR2,
> hire_date DATE,
> job_id VARCHAR2,
> salary NUMBER,
> commission_pct NUMBER,
> manager_id NUMBER,
> department_id NUMBER);
> PROCEDURE remove_employee (emp_id NUMBER);
> FUNCTION num_above_salary (emp_id NUMBER) RETURN NUMBER;
> END emp_actions;
> /
Package created.
Command> -- Package body:
> CREATE OR REPLACE PACKAGE BODY emp_actions AS
> -- Code for procedure hire_employee:
> PROCEDURE hire_employee (employee_id NUMBER,
> last_name VARCHAR2,
> first_name VARCHAR2,
> email VARCHAR2,
> phone_number VARCHAR2,
> hire_date DATE,
> job_id VARCHAR2,
> salary NUMBER,
> commission_pct NUMBER,
> manager_id NUMBER,
> department_id NUMBER) IS
> BEGIN
> INSERT INTO employees VALUES (employee_id,
> last_name,
> first_name,
> email,
> phone_number,
> hire_date,
> job_id,
> salary,
> commission_pct,
> manager_id,
> department_id);
> END hire_employee;
> -- Code for procedure remove_employee:
> PROCEDURE remove_employee (emp_id NUMBER) IS
> BEGIN
> DELETE FROM employees WHERE employee_id = emp_id;
> END remove_employee;
> -- Code for function num_above_salary:
> FUNCTION num_above_salary (emp_id NUMBER) RETURN NUMBER IS
> emp_sal NUMBER(8,2);
> num_count NUMBER;
> BEGIN
> SELECT salary INTO emp_sal FROM employees
> WHERE employee_id = emp_id;
> SELECT COUNT(*) INTO num_count FROM employees
> WHERE salary > emp_sal;
> RETURN num_count;
> END num_above_salary;
> END emp_actions;
> /
Package body created.
Command> BEGIN
> /* call function to return count of employees with salary
> greater than salary of employee with employee_id = 120
> */
> DBMS_OUTPUT.PUT_LINE
> ('Number of employees with higher salary: ' ||
> TO_CHAR(emp_actions.num_above_salary(120)));
> END;
> /
Number of employees with higher salary: 33
PL/SQL procedure successfully completed.
Verify the count of 33.
Command> SELECT salary FROM employees WHERE employee_id = 120; < 8000 > 1 row found. Command> SELECT COUNT (*) FROM employees WHERE salary > 8000; < 33 > 1 row found.
Now add an employee and verify results. Then, remove the employee and verify that the employee was deleted from the employees table.
Command> BEGIN
> emp_actions.hire_employee(300,
> 'Belden',
> 'Enrique',
> 'EBELDEN',
> '555.111.2222',
> '31-AUG-04',
> 'AC_MGR',
> 9000,
> .1,
> 101,
> 110);
> END;
> /
PL/SQL procedure successfully completed.
Command> SELECT * FROM employees WHERE employee_id = 300;
< 300, Belden, Enrique, EBELDEN, 555.111.2222, 2004-08-31 00:00:00, AC_MGR, 9000,
.1, 101, 110 >
1 row found.
Command> BEGIN
> emp_actions.remove_employee (300);
> END;
> /
PL/SQL procedure successfully completed.
Command> SELECT * FROM employees WHERE employee_id = 300;
0 rows found.
TimesTen supports private and public synonyms (aliases) for database objects, including PL/SQL procedures, functions, and packages. Synonyms are often used to mask object names and object owners or to simplify SQL statements.
To create a private synonym for package foopkg in your schema:
CREATE SYNONYM synfoopkg FOR foopkg;
To create a public synonym for foopkg:
CREATE PUBLIC SYNONYM pubfoopkg FOR foopkg;
Also see "Using synonyms for procedures and functions" and "Required privileges for PL/SQL statements and operations".
|
Note: You cannot create synonyms for individual member subprograms of a package.This is valid: create or replace public synonym pubtestpkg for testpkg; This is not valid: create or replace public synonym pubtestproc for testpkg.testproc; |
Wrapping is the process of hiding PL/SQL source code. You can wrap PL/SQL source code with the wrap utility, which processes an input SQL file and wraps only the PL/SQL units in the file, such as a package specifications, package bodies, functions, and procedures.
Consider the following example, which uses a file wrap_test.sql to define a procedure named wraptest. It then uses the wrap utility to process wrap_test.sql. The procedure is created with the source code hidden, and executes successfully. As a final step, the ALL_OBJECTS view is queried to see the wrapped source code.
Here are the contents of wrap_test.sql:
CREATE OR REPLACE PROCEDURE wraptest IS
TYPE emp_tab IS TABLE OF employees%ROWTYPE INDEX BY PLS_INTEGER;
all_emps emp_tab;
BEGIN
SELECT * BULK COLLECT INTO all_emps FROM employees;
FOR i IN 1..10
LOOP
DBMS_OUTPUT.PUT_LINE('Emp Id: ' || all_emps(i).employee_id);
END LOOP;
END;
/
In the example that follows, "$" is the UNIX prompt, "Command>" is the ttIsql prompt, and user input is shown in bold.
$ wrap iname=wrap_test.sql PL/SQL Wrapper: Release 11.2.0.2.0- Production on Wed Sep 14 12:59:27 2011 Copyright (c) 1993, 2009, Oracle. All rights reserved. Processing wrap_test.sql to wrap_test.plb $ cat wrap_test.plb CREATE OR REPLACE PROCEDURE wraptest wrapped a000000 1 abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd 7 124 12c YZ6L0v2ntFaqttW8hSJD5IHIYccwg+nwNfZqfHQCv/9kMJyznwdLh8FepNXpWS1fzVBDkTke LWlhFdFzCMfmmJ5GGrCwrqgngEhfRpq7ck5Dzsf7sDlnQeE3QGmb/yu9Dec1+JO2kOMlx3dq BuC7fR2f5sjDtBeDXiGCC0kJ5QBVregtoBckZNO9MoiWS4w0jF6T1CPY0Aoi/KUwxC8S8I8n amF5xGQDCYTDajs77orIGEqtX747k0YAO+r1e9adGUsVgZK1ONcTM/+Wit+LYKi7b03eJxdB +aaKn/Lh / $ ttisql sampledb_1122 Copyright (c) 1996-2011, Oracle. All rights reserved. Type ? or "help" for help, type "exit" to quit ttIsql. connect "DSN=sampledb_1122"; Connection successful: DSN=sampledb_1122;UID=myuserid;DataStore=.../install/info/DemoDataStore/ sampledb_1122;DatabaseCharacterSet=US7ASCII;ConnectionCharacterSet=US7ASCII;DRIVER =.../install/lib/libtten.so;PermSize=40;TempSize=32;TypeMode=0; (Default setting AutoCommit=1) Command> @wrap_test.plb CREATE OR REPLACE PROCEDURE wraptest wrapped a000000 1 abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd 7 124 12c YZ6L0v2ntFaqttW8hSJD5IHIYccwg+nwNfZqfHQCv/9kMJyznwdLh8FepNXpWS1fzVBDkTke LWlhFdFzCMfmmJ5GGrCwrqgngEhfRpq7ck5Dzsf7sDlnQeE3QGmb/yu9Dec1+JO2kOMlx3dq BuC7fR2f5sjDtBeDXiGCC0kJ5QBVregtoBckZNO9MoiWS4w0jF6T1CPY0Aoi/KUwxC8S8I8n amF5xGQDCYTDajs77orIGEqtX747k0YAO+r1e9adGUsVgZK1ONcTM/+Wit+LYKi7b03eJxdB +aaKn/Lh Procedure created. Command> SET SERVEROUTPUT ON Command> BEGIN > wraptest(); > END; > / Emp Id: 100 Emp Id: 101 Emp Id: 102 Emp Id: 103 Emp Id: 104 Emp Id: 105 Emp Id: 106 Emp Id: 107 Emp Id: 108 Emp Id: 109 PL/SQL procedure successfully completed. Command> SELECT text FROM all_source WHERE name = 'WRAPTEST'; < PROCEDURE wraptest wrapped a000000 1 abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd abcd 7 124 12c YZ6L0v2ntFaqttW8hSJD5IHIYccwg+nwNfZqfHQCv/9kMJyznwdLh8FepNXpWS1fzVBDkTke LWlhFdFzCMfmmJ5GGrCwrqgngEhfRpq7ck5Dzsf7sDlnQeE3QGmb/yu9Dec1+JO2kOMlx3dq BuC7fR2f5sjDtBeDXiGCC0kJ5QBVregtoBckZNO9MoiWS4w0jF6T1CPY0Aoi/KUwxC8S8I8n amF5xGQDCYTDajs77orIGEqtX747k0YAO+r1e9adGUsVgZK1ONcTM/+Wit+LYKi7b03eJxdB +aaKn/Lh > 1 row found.
In TimesTen, any operation that ends your transaction closes all cursors associated with the connection. This includes the following:
Any COMMIT or ROLLBACK statement
For PL/SQL users, any DDL statement
This is because when PL/SQL is enabled (the PLSQL first connection attribute is set to 1), the TimesTen DDLCommitBehavior general connection attribute must be set to 0, for Oracle Database behavior (autocommit DDL).
For example, consider the following scenario, where you want to recompile a set of procedures. This would not work, because the first time ALTER PROCEDURE is executed, the cursor (pnamecurs) would be closed:
declare
cursor pnamecurs is select * from all_objects where object_name like 'MYPROC%';
begin
for rec in pnamecurs loop
execute immediate 'alter procedure ' || rec.object_name || ' compile';
end loop;
end;
Instead, you can do something like the following, which fetches all the procedure names into an internal table then executes ALTER PROCEDURE on them with no active cursor.
declare
cursor pnamecurs is select * from all_objects where object_name like 'MYPROC%';
type tbl is table of c%rowtype index by binary_integer;
myprocs tbl;
begin
open pnamecurs;
fetch pnamecurs bulk collect into myprocs;
close pnamecurs;
for i in 1..myprocs.count loop
execute immediate 'alter procedure ' || myprocs(i).object_name || ' compile';
end loop;
end;
PL/SQL Developer's Guide
11g Release 2 (11.2.2)
E21639-03
September 2012
Oracle TimesTen In-Memory Database PL/SQL Developer's Guide, 11g Release 2 (11.2.2)
E21639-03
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TimesTen supports PL/SQL (Procedural Language Extension to SQL), a programming language that enables you to integrate procedural constructs with SQL in your database. TimesTen 11g Release 2 (11.2.2) implements the PL/SQL language from Oracle Database release 11.2.0.2. As such, most PL/SQL features present in that release of Oracle Database are also present in TimesTen, operating in essentially the same way. (Refer to Chapter 9, "TimesTen PL/SQL Support: Reference Summary" for differences.)
This chapter provides a brief introduction to TimesTen PL/SQL, covering the following topics:
PL/SQL support in TimesTen enables you to do the following:
Take full advantage of the PL/SQL programming language.
Execute PL/SQL from your client applications that use these APIs:
ODBC
JDBC
OCI
Pro*C/C++
ODP.NET
TTClasses
Execute TimesTen SQL from PL/SQL.
Create, alter, or drop standalone procedures, functions, packages and package bodies.
Use PL/SQL packages to extend your database functionality and to provide PL/SQL access to SQL features.
Handle exceptions and errors in your PL/SQL applications.
Set connection attributes in your database to customize your PL/SQL environment.
Alter session parameters so you can manage your PL/SQL environment.
Display PL/SQL metadata in your database by using PL/SQL system views.
This section provides an overview of PL/SQL operations in TimesTen, including discussion of how an application interacts with PL/SQL and how PL/SQL components interact with other components of TimesTen. The following topics are covered:
Figure 1-1 shows the PL/SQL components and their interactions with each other and with other TimesTen components during PL/SQL operations.
An application uses the API of its choice—ODBC, JDBC, OCI, Pro*C, or TTClasses—to send requests to the database. ODBC is the TimesTen native API, so each of the other APIs ultimately calls the ODBC layer.
The ODBC driver calls the TimesTen SQL parser to examine each incoming request and determine whether it is SQL or PL/SQL. The request is then passed to the appropriate subsystem within TimesTen. PL/SQL source and SQL statements are compiled, optimized and executed by the PL/SQL subsystem and SQL subsystem, respectively.
The PL/SQL compiler is responsible for generating executable code from PL/SQL source, while the SQL compiler does the same for SQL statements. Each compiler generates intermediate code that can then be executed by the appropriate PL/SQL or SQL execution engine. This executable code, along with metadata about the PL/SQL blocks, is then stored in tables in the database.
When PL/SQL blocks are executed, the PL/SQL execution engine is invoked. As PL/SQL blocks in turn invoke SQL, the PL/SQL execution engine will call the TimesTen SQL compiler and the TimesTen SQL execution engine to handle SQL execution.
|
Note: The introduction of PL/SQL into TimesTen has little impact on applications that do not use it. If applications execute SQL directly, then requests are passed from the TimesTen ODBC driver to the TimesTen SQL compiler and execution engine in the same way as in previous releases. |
PL/SQL processing in TimesTen is largely identical to its processing in Oracle Database. The PL/SQL compiler and execution engine that are included with TimesTen originated in Oracle Database, and the relationship between PL/SQL components and the SQL compiler and execution engine is comparable. The tables used to store PL/SQL units are the same in TimesTen and Oracle, as are the views that are available to query information about stored PL/SQL units.
Beyond these basic similarities, however, are some potentially significant differences. These are detailed in the following subsections:
In TimesTen, as in Oracle Database, PL/SQL blocks may include SQL statements. Consider the anonymous block in the following example:
Command> create table tab2 (x number, last_name VARCHAR2 (25) INLINE NOT NULL);
Command> declare
> x number;
> begin
> select salary into x from employees where last_name = 'Whalen';
> insert into tab2 values(x, 'Whalen');
> end;
> /
PL/SQL procedure successfully completed.
The PL/SQL compiler in TimesTen calls a copy of the Oracle SQL parser to analyze and validate the syntax of such SQL statements. This Oracle parser is included in TimesTen for this purpose. As part of this processing, PL/SQL may rewrite parts of the SQL statements (for example, by removing INTO clauses or replacing PL/SQL variables with binds). This processing is identical in TimesTen and in Oracle Database. The rewritten SQL statements are then included in the executable code for the PL/SQL block. When the PL/SQL block is executed, these SQL statements are compiled and executed by the TimesTen SQL subsystem.
In Oracle Database, the same SQL parser is used by the PL/SQL compiler and the SQL compiler. In TimesTen, however, different SQL parsers are used. TimesTen PL/SQL uses the Oracle Database SQL parser, while TimesTen SQL uses the native TimesTen SQL parser. This difference is typically, but not always, transparent to the end user. In particular, be aware of the following:
SQL statements in TimesTen PL/SQL programs must obey Oracle SQL syntax. While TimesTen SQL is generally a subset of Oracle SQL, there are some expressions that are permissible in TimesTen SQL but not in Oracle SQL. Such TimesTen-specific SQL operations cannot be used within PL/SQL except by using dynamic SQL through EXECUTE IMMEDIATE statements or the DBMS_SQL package. See "Dynamic SQL in PL/SQL (EXECUTE IMMEDIATE statement)".
SQL statements that would be permissible in Oracle Database will be accepted by the PL/SQL compiler as valid even if they cannot be executed by TimesTen. If SQL features are used that TimesTen does not support, compilation of a PL/SQL block may be successful, but a runtime error would occur when the PL/SQL block is executed.
In Oracle Database, PL/SQL blocks can invoke SQL statements, and SQL statements can in turn invoke PL/SQL functions. For example, a stored procedure can invoke an UPDATE statement that employs a user-written PL/SQL function in its WHERE clause.
In TimesTen, a SQL statement cannot invoke a PL/SQL function.
In addition, TimesTen does not support triggers.
There are two primary developer audiences for this document:
Developers experienced with Oracle Database and Oracle PL/SQL who want to learn how to use PL/SQL in TimesTen: These readers want to learn the differences between PL/SQL in Oracle and PL/SQL in TimesTen.
Developers experienced with TimesTen who are not familiar with PL/SQL: These readers need general information about PL/SQL.
The following subsections note areas of particular interest in this document for each audience.
Developers experienced with Oracle PL/SQL can bypass much of this document, which covers many general concepts of PL/SQL. Likely areas of interest, particularly differences in PL/SQL functionality between Oracle and TimesTen, include the following. Note that TimesTen-specific considerations are discussed at the end of Chapter 2, Chapter 3, and Chapter 4 and throughout Chapter 9.
"How to execute PL/SQL procedures and functions": This includes a comparison between how you can execute them in TimesTen and in Oracle.
"Differences in TimesTen: transaction behavior": This discusses cursor behavior when a transaction ends in TimesTen.
"Differences in TimesTen: data type considerations": This includes TimesTen-specific conversions, and types that TimesTen does not support.
"Differences in TimesTen: exception handing and error behavior": This describes differences in error support, handling, and reporting.
Chapter 6, "PL/SQL Installation and Environment": This includes discussion of TimesTen connection attributes.
Chapter 8, "TimesTen Supplied PL/SQL Packages": This documents the subset of Oracle PL/SQL packages that TimesTen supports.
Chapter 9, "TimesTen PL/SQL Support: Reference Summary": This reference chapter provides a detailed treatment of differences between TimesTen PL/SQL and Oracle PL/SQL.
Most of this document is geared toward readers without prior PL/SQL experience, especially prior TimesTen users who are not familiar with PL/SQL, and nearly the entire document should be useful. In particular, Chapter 2, "Programming Features in PL/SQL in TimesTen," will help these readers get started and Chapter 5, "Examples Using TimesTen SQL in PL/SQL," includes some additional examples.
Chapter 9, "TimesTen PL/SQL Support: Reference Summary," is geared toward differences between TimesTen PL/SQL and Oracle PL/SQL and may be of less interest.
After you have configured your environment, you can confirm that everything is set up correctly by compiling and running the TimesTen Quick Start demo applications. Refer to the Quick Start welcome page at install_dir/quickstart.html, especially the links under SAMPLE PROGRAMS, for information about the following:
Demo schema and setup: The build_sampledb script (.sh on UNIX or .bat on Windows) creates a sample database and demo schema. You must use this before you start using the demos.
Demo environment and setup: The ttquickstartenv script (.sh or .csh on UNIX or .bat on Windows), a superset of the ttenv script generally used for TimesTen setup, sets up the demo environment. You must use this each time you enter a session where you want to compile or run any of the demos.
Demos and setup: TimesTen provides demos for PL/SQL in a subdirectory under the quickstart/sample_code directory. For instructions on running the demos, see the README file in the subdirectory.
What the demos do: A synopsis of each demo is provided when you click PL/SQL under SAMPLE PROGRAMS.
This chapter describes the flexible error trapping and error handling you can use in your PL/SQL programs.
For more information on error-handling and exceptions in PL/SQL, see "PL/SQL Error Handling" in Oracle Database PL/SQL Language Reference.
See the end of this chapter for TimesTen-specific considerations.
The following topics are covered:
This section provides an overview of exceptions in PL/SQL programming, covering the following topics:
An exception is a PL/SQL error that is raised during program execution, either implicitly by TimesTen or explicitly by your program. Handle an exception by trapping it with a handler or propagating it to the calling environment.
For example, if your SELECT statement returns multiple rows, TimesTen returns an error (exception) at runtime. As the following example shows, you would see TimesTen error 8507, then the associated ORA error message. (ORA messages, originally defined for Oracle Database, are similarly implemented by TimesTen.)
Command> DECLARE
> v_lname VARCHAR2 (15);
> BEGIN
> SELECT last_name INTO v_lname
> FROM employees
> WHERE first_name = 'John';
> DBMS_OUTPUT.PUT_LINE ('Last name is :' || v_lname);
> END;
> /
8507: ORA-01422: exact fetch returns more than requested number of rows
8507: ORA-06512: at line 4
The command failed.
You can handle such exceptions in your PL/SQL block so that your program completes successfully. For example:
Command> DECLARE
> v_lname VARCHAR2 (15);
> BEGIN
> SELECT last_name INTO v_lname
> FROM employees
> WHERE first_name = 'John';
> DBMS_OUTPUT.PUT_LINE ('Last name is :' || v_lname);
> EXCEPTION
> WHEN TOO_MANY_ROWS THEN
> DBMS_OUTPUT.PUT_LINE (' Your SELECT statement retrieved multiple
> rows. Consider using a cursor.');
> END;
> /
Your SELECT statement retrieved multiple rows. Consider using a cursor.
PL/SQL procedure successfully completed.
There are three types of exceptions:
Predefined exceptions are error conditions that are defined by PL/SQL.
Non-predefined exceptions include any standard TimesTen errors.
User-defined exceptions are exceptions specific to your application.
In TimesTen, these three types of exceptions are used in the same way as in Oracle Database.
| Exception | Description | How to handle |
|---|---|---|
| Predefined TimesTen error | One of approximately 20 errors that occur most often in PL/SQL code | You are not required to declare these exceptions. They are predefined by TimesTen. TimesTen implicitly raises the error. |
| Non-predefined TimesTen error | Any other standard TimesTen error | These must be declared in the declarative section of your application. TimesTen implicitly raises the error and you can use an exception handler to catch the error. |
| User-defined error | Error defined and raised by the application | These must be declared in the declarative section. The developer raises the exception explicitly. |
This section describes how to trap predefined TimesTen errors or user-defined errors.
Trap a predefined TimesTen error by referencing its predefined name in your exception-handling routine. PL/SQL declares predefined exceptions in the STANDARD package.
Table 4-1 lists predefined exceptions supported by TimesTen, the associated ORA error numbers and SQLCODE values, and descriptions of the exceptions.
Also see "Unsupported predefined errors".
Table 4-1 Predefined exceptions
| Exception name | Oracle error number | SQLCODE | Description |
|---|---|---|---|
|
|
|
-6530 |
Program attempted to assign values to the attributes of an uninitialized object. |
|
|
|
-6592 |
None of the choices in the |
|
|
|
-6531 |
Program attempted to apply collection methods other than EXISTS to an uninitialized nested table or varray, or program attempted to assign values to the elements of an uninitialized nested table or varray. |
|
|
|
-6511 |
Program attempted to open an already opened cursor. |
|
|
|
-1 |
Program attempted to insert duplicate values in a column that is constrained by a unique index. |
|
|
|
-1001 |
There is an illegal cursor operation. |
|
|
|
-1722 |
Conversion of character string to number failed. |
|
|
|
+100 |
Single row |
|
|
|
-6501 |
PL/SQL has an internal problem. |
|
|
|
-6504 |
Host cursor variable and PL/SQL cursor variable involved in an assignment statement have incompatible return types. |
|
|
|
-6500 |
PL/SQL ran out of memory or memory was corrupted. |
|
|
|
-6533 |
A program referenced a nested table or varray using an index number larger than the number of elements in the collection. |
|
|
|
-6532 |
A program referenced a nested table or varray element using an index number that is outside the legal range (for example, -1). |
|
|
|
-1410 |
The conversion of a character string into a universal rowid failed because the character string does not represent a |
|
|
|
-1422 |
Single row |
|
|
|
-6502 |
An arithmetic, conversion, truncation, or size constraint error occurred. |
|
|
|
-1476 |
A program attempted to divide a number by zero. |
Example 4-1 Using the ZERO_DIVIDE predefined exception
In this example, a PL/SQL program attempts to divide by 0. The ZERO_DIVIDE predefined exception is used to trap the error in an exception-handling routine.
Command> DECLARE v_invalid PLS_INTEGER;
> BEGIN
> v_invalid := 100/0;
> EXCEPTION
> WHEN ZERO_DIVIDE THEN
> DBMS_OUTPUT.PUT_LINE ('Attempt to divide by 0');
> END;
> /
Attempt to divide by 0
PL/SQL procedure successfully completed.
You can define your own exceptions in PL/SQL in TimesTen, and you can raise user-defined exceptions explicitly with either the PL/SQL RAISE statement or the RAISE_APPLICATION_ERROR procedure.
The RAISE statement stops normal execution of a PL/SQL block or subprogram and transfers control to an exception handler. RAISE statements can raise predefined exceptions, or user-defined exceptions whose names you decide.
Example 4-2 Using RAISE statement to trap user-defined exception
In this example, the department number 500 does not exist, so no rows are updated in the departments table. The RAISE statement is used to explicitly raise an exception and display an error message, returned by the SQLERRM built-in function, and an error code, returned by the SQLCODE built-in function. Use the RAISE statement by itself within an exception handler to raise the same exception again and propagate it back to the calling environment.
Command> DECLARE
> v_deptno NUMBER := 500;
> v_name VARCHAR2 (20) := 'Testing';
> e_invalid_dept EXCEPTION;
> BEGIN
> UPDATE departments
> SET department_name = v_name
> WHERE department_id = v_deptno;
> IF SQL%NOTFOUND THEN
> RAISE e_invalid_dept;
> END IF;
> ROLLBACK;
> EXCEPTION
> WHEN e_invalid_dept THEN
> DBMS_OUTPUT.PUT_LINE ('No such department');
> DBMS_OUTPUT.PUT_LINE (SQLERRM);
> DBMS_OUTPUT.PUT_LINE (SQLCODE);
> END;
> /
No such department
User-Defined Exception
1
PL/SQL procedure successfully completed.
The command succeeded.
|
Note: Given the same error condition in TimesTen and Oracle Database,SQLCODE will return the same error code, but SQLERRM will not necessarily return the same error message. This is also noted in "TimesTen error messages and SQL codes". |
Use the RAISE_APPLICATION_ERROR procedure in the executable section or exception section (or both) of your PL/SQL program. TimesTen reports errors to your application so you can avoid returning unhandled exceptions.
Use an error number between -20,000 and -20,999. Specify a character string up to 2,048 bytes for your message.
Example 4-3 Using the RAISE_APPLICATION_ERROR procedure
This example attempts to delete from the employees table where last_name=Patterson. The RAISE_APPLICATION_ERROR procedure raises the error, using error number -20201.
Command> DECLARE
> v_last_name employees.last_name%TYPE := 'Patterson';
> BEGIN
> DELETE FROM employees WHERE last_name = v_last_name;
> IF SQL%NOTFOUND THEN
> RAISE_APPLICATION_ERROR (-20201, v_last_name || ' does not exist');
> END IF;
> END;
> /
8507: ORA-20201: Patterson does not exist
8507: ORA-06512: at line 6
The command failed.
You can use the show errors command in ttIsql to see details about errors you encounter in executing anonymous blocks or compiling packages, procedures, or functions. This is shown in Example 4-4.
Example 4-4 ttIsql show errors command
Again consider Example 2-17. Assume the same package specification shown there, which declares the procedures and functions hire_employee, remove_employee, and num_above_salary. But instead of the body definition shown there, consider the following, which defines hire_employee and num_above_salary but not remove_employee:
CREATE OR REPLACE PACKAGE BODY emp_actions AS
-- Code for procedure hire_employee:
PROCEDURE hire_employee (employee_id NUMBER,
last_name VARCHAR2,
first_name VARCHAR2,
email VARCHAR2,
phone_number VARCHAR2,
hire_date DATE,
job_id VARCHAR2,
salary NUMBER,
commission_pct NUMBER,
manager_id NUMBER,
department_id NUMBER) IS
BEGIN
INSERT INTO employees VALUES (employee_id,
last_name,
first_name,
email,
phone_number,
hire_date,
job_id,
salary,
commission_pct,
manager_id,
department_id);
END hire_employee;
-- Code for function num_above_salary:
FUNCTION num_above_salary (emp_id NUMBER) RETURN NUMBER IS
emp_sal NUMBER(8,2);
num_count NUMBER;
BEGIN
SELECT salary INTO emp_sal FROM employees
WHERE employee_id = emp_id;
SELECT COUNT(*) INTO num_count FROM employees
WHERE salary > emp_sal;
RETURN num_count;
END num_above_salary;
END emp_actions;
/
Attempting this body definition after the original package specification results in the following:
Warning: Package body created with compilation errors.
To get more information, run ttIsql and use the command show errors. In this example, show errors provides the following:
Command> show errors; Errors for PACKAGE BODY EMP_ACTIONS: LINE/COL ERROR -------- ----------------------------------------------------------------- 13/13 PLS-00323: subprogram or cursor 'REMOVE_EMPLOYEE' is declared in a package specification and must be defined in the package body
You should be aware of some error-related behaviors that differ between TimesTen PL/SQL and Oracle PL/SQL:
TimesTen PL/SQL transaction and rollback behavior for unhandled exceptions
Possibility of runtime errors after clean compile (use of Oracle SQL parser)
TimesTen PL/SQL differs from Oracle PL/SQL in a scenario where an application executes PL/SQL in the middle of a transaction, and an unhandled exception occurs during execution of the PL/SQL. Oracle will roll back to the beginning of the anonymous block. TimesTen will not roll back.
An application should always handle any exception that results from execution of a PL/SQL block, as in the following example, run with autocommit disabled:
create table mytable (num int not null primary key);
set serveroutput on
insert into mytable values(1);
begin
insert into mytable values(2);
insert into mytable values(1);
exception
when dup_val_on_index then
dbms_output.put_line('oops:' || sqlerrm);
rollback;
end;
select * from mytable;
commit;
The second INSERT will fail because values must be unique, so there will be an exception and the program will perform a rollback. Running this in TimesTen results in the following.
oops:TT0907: Unique constraint (MYTABLE) violated at Rowid <BMUFVUAAABQAAAADjq> select * from mytable; 0 rows found.
The result is equivalent in Oracle Database, with the SELECT results showing no rows.
Now consider a TimesTen example where the exception is not handled, again run with autocommit disabled:
create table mytable (num int not null primary key); set serveroutput on insert into mytable values(1); begin insert into mytable values(2); insert into mytable values(1); end; select * from mytable; commit;
In TimesTen, the SELECT query will indicate execution of the first two inserts:
907: Unique constraint (MYTABLE) violated at Rowid <BMUFVUAAABQAAAADjq> 8507: ORA-06512: at line 3 The command failed. select * from mytable; < 1 > < 2 > 2 rows found.
If you execute this in Oracle, there will be a rollback to the beginning of the PL/SQL block, so the SELECT results will indicate execution of only the first insert:
ORA-00001: unique constraint (SYSTEM.SYS_C004423) violated
ORA-06512: at line 3
NUM
----------
1
|
Notes:
|
Given the same error condition, TimesTen does not guarantee that the error message returned by TimesTen will be the same as the message returned by Oracle Database, although the SQL code will be the same. Therefore, the information returned by the SQLERRM function may be different, but that returned by the SQLCODE function will be the same.
For further information:
Example 4-2 uses SQLERRM and SQLCODE.
Refer to "Warnings and Errors" in Oracle TimesTen In-Memory Database Error Messages and SNMP Traps for information about specific TimesTen error messages.
Refer to "SQLERRM Function" and "SQLCODE Function" in Oracle Database PL/SQL Language Reference for general (and Oracle-specific) information.
Oracle Database does not have the concept of runtime warnings, so Oracle PL/SQL does not support warnings.
TimesTen does have the concept of warnings, but because the TimesTen PL/SQL implementation is based on the Oracle PL/SQL implementation, TimesTen PL/SQL does not support warnings.
As a result, in TimesTen you could execute a SQL statement and see a resulting warning, but if you execute the same statement through PL/SQL you will not see the warning.
"Trapping predefined TimesTen errors" lists predefined exceptions supported by TimesTen, the associated ORA error numbers and SQLCODE values, and descriptions of the exceptions.
Table 4-2 notes predefined exceptions that are not supported by TimesTen.
Table 4-2 Predefined exceptions not supported by TimesTen
| Exception name | Oracle error number | SQLCODE | Description |
|---|---|---|---|
|
|
|
-1017 |
User name or password is invalid. |
|
|
|
-1012 |
Program issued a database call without being connected to the database. |
|
|
|
-30625 |
Program attempted to invoke a |
|
|
|
-51 |
Timeout occurred while the database was waiting for a resource. |
The TimesTen PL/SQL implementation uses the Oracle SQL parser in compiling PL/SQL programs. (This is discussed in "PL/SQL in TimesTen versus PL/SQL in Oracle Database".) As a result, if your program uses Oracle syntax or Oracle built-in procedures that are not supported by TimesTen, the issue will not be discovered during compilation. A runtime error would occur during program execution, however.
TimesTen SQL includes several constructs that are not present in Oracle SQL. The PL/SQL language does not include these constructs. To use TimesTen-specific SQL from PL/SQL, execute the SQL statements using the EXECUTE IMMEDIATE statement. This will avoid compilation errors.
For lists of TimesTen-specific SQL and expressions, see "Compatibility Between TimesTen and Oracle" in Oracle In-Memory Database Cache User's Guide.
For more information about EXECUTE IMMEDIATE, refer to "Dynamic SQL in PL/SQL (EXECUTE IMMEDIATE statement)".
Oracle TimesTen In-Memory Database is a memory-optimized relational database. Deployed in the application tier, TimesTen operates on databases that fit entirely in physical memory using standard SQL interfaces. High availability for the in-memory database is provided through real-time transactional replication.
TimesTen supports a variety of programming interfaces, including PL/SQL (Oracle procedural language extension for SQL), ODBC (Open Database Connectivity), JDBC (Java Database Connectivity), OCI (Oracle Call Interface), Pro*C/C++ (Oracle precompiler for embedded SQL and PL/SQL instructions in C or C++ code), TTClasses (TimesTen C++ Interface Classes), and ODP.NET (Oracle Data Provider for .NET).
This document covers TimesTen support for PL/SQL.
The following topics are discussed in the preface:
This document is intended for anyone developing or supporting applications that use PL/SQL with TimesTen. Although it provides some overview, you should be familiar with PL/SQL or have access to more detailed documentation. This manual emphasizes TimesTen-specific functionality.
You should also be familiar with TimesTen, SQL (Structured Query Language), and database operations.
You would typically use PL/SQL through some programming interface such as those mentioned above, so should also consult the appropriate TimesTen developer documentation.
Also see "Audiences for this document", which goes into more detail.
TimesTen documentation is available on the product distribution media and on the Oracle Technology Network.
http://www.oracle.com/technetwork/products/timesten/documentation/
Oracle documentation is also available on the Oracle Technology network. This may be especially useful for Oracle features that TimesTen supports but does not attempt to fully document.
http://www.oracle.com/technetwork/database/enterprise-edition/documentation/
In particular, these Oracle documents may be of interest:
Oracle Database PL/SQL Language Reference
Oracle Database PL/SQL Packages and Types Reference
Oracle Database SQL Language Reference
Oracle Database Reference
In addition, numerous third-party documents are available that describe PL/SQL in detail.
TimesTen supports multiple platforms. Unless otherwise indicated, the information in this guide applies to all supported platforms. The term Windows applies to all supported Windows platforms. The term UNIX applies to all supported UNIX and Linux platforms. Refer to the "Platforms" section in Oracle TimesTen In-Memory Database Release Notes for specific platform versions supported by TimesTen.
|
Note: In TimesTen documentation, the terms "data store" and "database" are equivalent. Both terms refer to the TimesTen database unless otherwise noted. |
This document uses the following text conventions:
| Convention | Meaning |
|---|---|
| italic | Italic type indicates terms defined in text, book titles, or emphasis. |
monospace | Monospace type indicates commands, URLs, procedure and function names, package names, attribute names, directory names, file names, text that appears on the screen, or text that you enter. |
italic monospace | Italic monospace type indicates a placeholder or a variable in a code example for which you specify or use a particular value, such as in the following example:
Replace |
| [ ] | Square brackets indicate that an item in a command line is optional. |
| { } | Curly braces indicated that you must choose one of the items separated by a vertical bar ( | ) in a command line. |
| | | A vertical bar (or pipe) separates alternative arguments. |
| . . . | An ellipsis (. . .) after an argument indicates that you may use more than one argument on a single command line. An ellipsis in a code example indicates that what is shown is only a partial example. |
| % | The percent sign indicates the UNIX shell prompt. |
TimesTen documentation uses the following variables to identify path, file and user names.
| Convention | Meaning |
|---|---|
install_dir | The path that represents the directory where TimesTen is installed. |
TTinstance | The instance name for your specific installation of TimesTen. Each installation of TimesTen must be identified at installation time with a unique instance name. This name appears in the installation path. |
bits or bb | Two digits, either 32 or 64, that represent either a 32-bit or 64-bit operating system. |
release or rr | The first three parts in a release number, with or without dots. The first three parts of a release number represent a major TimesTen release. For example, 1122 or 11.2.2 represents TimesTen 11g Release 2 (11.2.2). |
DSN | TimesTen data source name (for the TimesTen database). |
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