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TimesTen and Oracle IMDB Cache support the Oracle Call Interface (OCI) for C or C++ programs.
This chapter provides an overview and TimesTen-specific information regarding OCI, especially emphasizing differences between using OCI with TimesTen versus with Oracle Database. For complete information about OCI, you can refer to Oracle Call Interface Programmer's Guide in the Oracle Database library.
Also note that Chapter 2, "Working with TimesTen Databases in ODBC", contains information that may be of general interest regarding TimesTen features.
The following topics are covered:
OCI is an API that provides functions you can use to access the database server and control SQL execution. OCI supports the data types, calling conventions, syntax, and semantics of the C and C++ programming languages. You compile and link an OCI program much as you would any C or C++ program. There is no preprocessing or precompilation step.
The OCI library of database access and retrieval functions is in the form of a dynamic runtime library that can be linked into an application at runtime. The OCI library includes the following functional areas:
SQL access functions
Data type mapping and manipulation functions
The following are among the many useful features that OCI provides or supports:
Statement caching
Dynamic SQL
Facilities to treat transaction control, session control, and system control statements like DML statements
Description functionality to expose layers of server metadata
Ability to associate commit requests with statement executions to reduce round trips
Optimization of queries using transparent prefetch buffers to reduce round trips
Thread safety that eliminates the need for mutual exclusive locks on OCI handles
For general information about OCI, you can refer to Oracle Call Interface Programmer's Guide, included with the Oracle Database documentation set.
This chapter contains information specific to using OCI with TimesTen and IMDB Cache. For supported features, TimesTen OCI syntax and usage is the same as that in Oracle Database.
This section covers the following topics:
TimesTen OCI depends on the Oracle Database client library and the TimesTen ODBC libraries. TimesTen OCI support enables you to run many existing OCI applications with TimesTen direct connections or client/server connections. It also enables you to use other Oracle Database products, such as Pro*C/C++ and ODP.NET, that use OCI as a database interface. (You can also call PL/SQL from OCI, Pro*C/C++, and ODP.NET applications.) Figure 3-1 shows where OCI support is positioned in the TimesTen architecture.
TimesTen provides Oracle Instant Client as the OCI client library. This is configured through the appropriate ttenv
script, as discussed in "Setting the environment for development".
Figure 3-1 OCI in the TimesTen architecture
TimesTen 11g Release 2 (11.2.2) OCI is based on Oracle Database release 11.2.0.2 OCI and supports the contemporary OCI 8 style APIs. For example, the OCIStmtExecute()
function is supported but not the older oexec()
function. See "Obsolete OCI Routines" in Oracle Call Interface Programmer's Guide in the Oracle Database documentation.
This section discusses TimesTen OCI support for globalization.
To specify a character set for the connection, OCI programs can set the NLS_LANG
environment variable or call OCIEnvNlsCreate()
. The setting in the sys.odbc.ini
or user odbc.ini
file is used by default if not overridden by NLS_LANG
or OCIEnvNlsCreate()
. Setting the character set explicitly is recommended. The default is typically AMERICAN_AMERICA.US7ASCII
.
Note that because TimesTen OCI does not support language or locale (territory) settings, the language and territory components of NLS_LANG
, such as AMERICAN_AMERICA
above, are ignored. Even when not specifying the language and locale, however, you must still have the period in front of the character set when setting NLS_LANG
. For example, either of the following would work, although AMERICAN_AMERICA
is ignored:
NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1
Or:
NLS_LANG=.WE8ISO8859P1
Notes:
|
TimesTen OCI also supports the following additional globalization features. These can be set as environment variables, TimesTen general connection attributes, or TimesTen ODBC connection options. For the connection options, the names here are prepended by "TT_
". An environment variable setting takes precedence over a corresponding connection attribute or connection option setting. A connection option setting takes precedence over a corresponding connection attribute setting.
NLS_LENGTH_SEMANTICS
: By default, the lengths of character data types CHAR
and VARCHAR2
are specified in bytes, not characters. For single-byte character encoding this works well. For multibyte character encoding, you can use NLS_LENGTH_SEMANTICS
to create CHAR
and VARCHAR2
columns using character-length semantics instead. Supported settings are BYTE
(default) and CHAR
. (NCHAR
and NVARCHAR2
columns are always character-based. Existing columns are not affected.)
NLS_SORT
: This specifies the type of sort for character data. It overrides the default value from NLS_LANGUAGE
. Valid values are BINARY
or any linguistic sort name supported by TimesTen. For example, to specify the German linguistic sort sequence, set NLS_SORT=German
.
NLS_NCHAR_CONV_EXCP
: This determines whether an error is reported when there is data loss during an implicit or explicit character type conversion between NCHAR
or NVARCHAR
data and CHAR
or VARCHAR2
data. Valid settings are TRUE
and FALSE
. The default value is FALSE
, resulting in no error being reported.
Refer to "Globalization Support" in Oracle TimesTen In-Memory Database Operations Guide and "Setting Up a Globalization Support Environment" in Oracle Database Globalization Support Guide for additional information on these environment variables and related features. See "Option support for SQLSetConnectOption and SQLGetConnectOption" for information about TimesTen connection option support.
This section discusses the following areas of restrictions and differences for OCI in TimesTen compared to in the Oracle Database:
TimesTen does not support OCI calls that are related to functionality that does not exist in TimesTen or IMDB Cache. For example, TimesTen and IMDB Cache do not support these Oracle Database features:
Advanced Queuing
Any Data
Object support
Collections
Cartridge Services
Direct path loading
Date/time intervals
Iterators
BFILEs
Cryptographic Toolkit
XML DB support
Spatial Services
Event handling
Session switching
Scrollable cursors
TimesTen OCI has the following restrictions:
The TypeMode
data store attribute must be set to 0, which corresponds to Oracle Database behavior.
The DuplicateBindMode
general connection attribute must be set to 0, which corresponds to Oracle Database behavior.
The DDLCommitBehavior
general connection attribute must be set to 0, which corresponds to Oracle Database behavior.
Asynchronous calls are not supported.
Connection pooling and session pooling are not supported.
Describing objects with OCIDescribeAny()
is supported only by name. Describing PL/SQL objects is not supported. (Also see the entry for this function under "Supported OCI calls".)
TimesTen Client/Server automatic client failover is not supported.
The TNSPING
utility does not recognize connections to TimesTen.
Retrieving implicit ROWID
values from INSERT
, UPDATE
, and DELETE
statements is not supported. (This is supported for SELECT FOR UPDATE
statements, however.)
TimesTen built-in procedures that return result sets are not supported directly.
Only a single REF CURSOR can be returned from a PL/SQL block, procedure call, or function call.
Binding and defining of structures through OCIBindArrayOfStruct()
and OCIDefineArrayOfStruct()
is supported for SQL statements but not for PL/SQL. (Also see the entries for these functions under "Supported OCI calls".)
Oracle Database utilities such as SQL*Plus and SQL*Loader are not supported. (In TimesTen, you can use ttIsql
instead of SQL*Plus and ttBulkCp
instead of SQL*Loader. See "Utilities" in Oracle TimesTen In-Memory Database Reference.)
Array binding, the ability to bind arrays into PL/SQL statements, is supported for associative arrays (index-by tables or PL/SQL tables) but is not supported for varrays (variable size arrays) or nested tables. (See "Associative array bindings in TimesTen OCI".)
Be aware of the following:
Both TimesTen and Oracle Database support XA, but TimesTen does not support XA through OCI.
With OCI, TimesTen automatically disables autocommit for DML statements. Transactions should be explicitly committed or rolled back when finished.
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.
If you have an existing OCI program and want to see whether it uses OCI features that TimesTen does not support, you can use the ttSrcScan
command line utility to scan your program for unsupported functions, types, type codes, attributes, modes, and constants. This is a standalone utility that can be run without TimesTen or Oracle Database being installed and runs on any platform supported by TimesTen. It reads source code files as input and creates HTML and text files as output. If the utility finds unsupported items, then they are logged and alternatives are suggested. You can find the ttSrcScan
executable in the quickstart/sample_util
directory in your TimesTen installation.
Specify an input file or directory for the program to be scanned and an output directory for the ttSrcScan
reports. Other options are available as well. See the README file in the sample_util
directory for information.
This section discusses the following topics for getting started with a TimesTen OCI application:
Environment variables for executing a TimesTen OCI application are described in Table 3-1. Settings apply to both direct connections and client/server connections except as noted.
After installation, you can modify environment variables as appropriate through the TimesTen install_dir
/bin/ttenv
script or quickstart/ttquickstartenv
script applicable to your operating system. Also see "Setting the environment for development".
You can also use the TimesTen OCI and Pro*C/C++ Makefiles provided with the Quick Start demos to implement appropriate environment settings. These are in the following locations:
quickstart/sample_code/oci/ quickstart/sample_code/proc/
Refer to "Environment variables" in Oracle TimesTen In-Memory Database Installation Guide for additional information about environment variables and ttenv
.
Note: To ensure proper generation of OCI programs to be run on TimesTen, do not setORACLE_HOME (or unset it if it was set previously) for OCI compilations. |
Table 3-1 Environment variables for TimesTen OCI
Variable | Required or optional | Settings |
---|---|---|
|
Required |
Must be set so that the TimesTen Instant Client directory precedes the Oracle Database libraries in the path. The path will be set properly if you use either of the following scripts under bin/ttenv quickstart/ttquickstartenv |
|
Required if you use the |
Specifies the directory where the |
|
Optional |
You can use this, whichever is appropriate for your platform, instead of specifying the See "Connecting to a TimesTen database from OCI" for more information. |
|
Optional |
See "Character sets". Only the character set component is honored and it must indicate a character set supported by TimesTen. The language and territory values are ignored. This environment variable overrides the TimesTen default character set. |
|
Optional |
See "Additional globalization features". The sort order must be a value supported by TimesTen. This overrides the TimesTen |
|
Optional |
See "Additional globalization features". This overrides the TimesTen |
|
Optional |
See "Additional globalization features". This overrides the TimesTen |
Note: Refer to "NLS general connection attributes" in Oracle TimesTen In-Memory Database Reference for information about the NLS connection attributes mentioned in the table. |
No changes are required between Oracle Database and TimesTen for the steps to compile and link an OCI application.
OCI programs that use the Oracle Client 11.2.0.2 library do not have to be recompiled or relinked to be executed with TimesTen.
TimesTen OCI uses the Oracle Instant Client to connect to the TimesTen database. You can connect to the database through either the tnsnames
or the easy connect naming method, similarly to how you would connect to an Oracle database through those methods.
This section covers the following topics:
Refer to "Configuring Naming Methods" in Oracle Database Net Services Administrator's Guide for additional information about tnsnames
, easy connect, and the tnsnames.ora
file.
Notes:
|
TimesTen supports tnsnames
syntax. You can use a TimesTen tnsnames.ora
entry the same way you would use an Oracle tnsnames.ora
entry.
The syntax of a TimesTen entry in tnsnames.ora
is as follows:
tns_entry = (DESCRIPTION = (CONNECT_DATA = (SERVICE_NAME = dsn) (SERVER = timesten_direct | timesten_client)))
Where tns_entry
is the arbitrary TNS name you assign to the entry. You can use this as the dbname
argument in OCILogon()
, OCILogon2()
, and OCIServerAttach()
calls.
DESCRIPTION
and CONNECT_DATA
are required as shown.
For SERVICE_NAME
, dsn
must be a TimesTen DSN that is configured in the sys.odbc.ini
or user odbc.ini
file that is visible to a user running your OCI application. On Windows, the DSN can be specified by using the ODBC Data Source Administrator. See "Managing TimesTen Databases" in Oracle TimesTen In-Memory Database Operations Guide.
For SERVER
, timesten_direct
specifies a direct connection to TimesTen or timesten_client
specifies a client/server connection. If you choose timesten_client
, the DSN must be configured as a client/server database.
As always, the host and port of the TimesTen server are determined from entries in the sys.ttconnect.ini
file, according to the DSN. See "Working with the TimesTen Client and Server" in Oracle TimesTen In-Memory Database Operations Guide.
Here is a sample tnsnames.ora
entry for a direct connection:
my_tnsname = (DESCRIPTION = (CONNECT_DATA = (SERVICE_NAME = my_dsn) (SERVER = timesten_direct)))
You can use the TNS name, my_tnsname
, in either of the following ways:
Specify "my_tnsname
" for the dbname
argument in your OCI logon call.
Specify an empty string for dbname
and set TWO_TASK
or LOCAL
to "my_tnsname
".
For example:
OCILogon2(envhp, errhp, &svchp, (text *)"user1", (ub4)strlen("user1"), (text *)"pwd1", (ub4)strlen("pwd1"), (text *)"my_tnsname", (ub4)strlen((char*)"my_tnsname"), OCI_DEFAULT));
Refer to "Connect, Authorize, and Initialize Functions" in Oracle Call Interface Programmer's Guide for details about OCI logon calling sequences.
Or on a UNIX system, for example, you can set TWO_TASK
to "my_tnsname
" and use an OCI logon call with an empty string for dbname
:
OCILogon2(envhp, errhp, &svchp, (text *)"user1", (ub4)strlen("user1"), (text *)"pwd1", (ub4)strlen("pwd1"), (text *)"", (ub4)0, OCI_DEFAULT));
TimesTen supports easy connect syntax, which enhances the Instant Client package by allowing connections to be made without configuring tnsnames.ora
. An easy connect string has syntax similar to a URL, in the following format:
[//]host[:port]/service_name:server[/instance]
The initial double-slash is optional. A host name must be specified to satisfy easy connect syntax, but is otherwise ignored by TimesTen. The name "localhost
" is typically used by convention. Any value specified for the port is also ignored. For client/server connections, the host and port of the TimesTen server are determined from entries in the sys.ttconnect.ini
file, according to the TimesTen DSN.
Specify the DSN for service_name
. Specify timesten_client
or timesten_direct
, as appropriate, for server
.
TimesTen ignores the instance
field and does not require that it be specified.
For example, the following easy connect string connects to a TimesTen server using the client/server libraries. Assume a DSN ttclient
in the sys.odbc.ini
file is resolved as a client/server data source and connects to the corresponding host and port specified in the sys.ttconnect.ini
file:
"localhost/ttclient:timesten_client"
The following easy connect string is for a direct connection to TimesTen. Assume the DSN ttdirect
is defined in sys.odbc.ini
:
"localhost/ttdirect:timesten_direct"
You can use an easy connect string in either of the following ways:
Specify it for the dbname
argument in your OCI logon call.
Specify an empty string for dbname
and set TWO_TASK
or LOCAL
to the easy connect string, in quotes.
For example:
OCILogon2(envhp, errhp, &svchp, (text *)"user1", (ub4)strlen("user1"), (text *)"pwd1", (ub4)strlen("pwd1"), (text *)"localhost/ttclient:timesten_client", (ub4)strlen((char*)"localhost/ttclient:timesten_client"), OCI_DEFAULT));
Refer to "Connect, Authorize, and Initialize Functions" in Oracle Call Interface Programmer's Guide for details about OCI logon calling sequences.
Or on a UNIX system, for example, you can set TWO_TASK
to "localhost/ttclient:timesten_client
" and use an OCI logon call with an empty string for dbname
:
OCILogon2(envhp, errhp, &svchp, (text *)"user1", (ub4)strlen("user1"), (text *)"pwd1", (ub4)strlen("pwd1"), (text *)"", (ub4)0, OCI_DEFAULT));
If a sqlnet.ora
file is present, it specifies the naming methods that will be tried and the order in which they will be tried. The Instant Client will look for a sqlnet.ora
file at the TNS_ADMIN
location, if applicable. If TNS_ADMIN
has not been set but ORACLE_HOME
has been (such as if you had a previous Instant Client installation), the default sqlnet.ora
location is the Oracle Database default location as noted in "Parameters for the sqlnet.ora File" in Oracle Database Net Services Reference.
If sqlnet.ora
is found and does not indicate a particular naming method, you cannot use that method. If sqlnet.ora
is not found, you can use either method.
In TimesTen, sample copies of tnsnames.ora
and sqlnet.ora
are in the install_dir
/network/admin/samples
directory. Here is the sqlnet.ora
file that TimesTen provides, which supports both tnsnames
and easy connect ("EZCONNECT
"):
# To use ezconnect syntax or tnsnames, the following entries must be # included in the sqlnet.ora configuration. # NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
With this file, TimesTen will first look for tnsnames
syntax in your OCI logon calls. If it cannot find tnsnames
syntax, it will look for easy connect syntax.
You can connect through OCI as an externally identified user (external user) by specifying the user name in brackets, such as "[myadmin]
", and the password as an empty string, "".
In particular, this is useful in connecting as the instance administrator, which in TimesTen is always an external user.
Adapting an earlier example:
OCILogon2(envhp, errhp, &svchp, (text *)"[myadmin]", (ub4)strlen("[myadmin]"), (text *)"", (ub4)strlen(""), (text *)"my_tnsname", (ub4)strlen((char*)"my_tnsname"), OCI_DEFAULT));
This functionality uses OCI proxy syntax. You can refer to the discussion of client access through a proxy in Oracle Call Interface Programmer's Guide.
Errors under TimesTen OCI applications return Oracle Database error codes. TimesTen attempts to report the same error code as Oracle Database would under similar conditions. The error messages may come from either the TimesTen catalog or the Oracle Database catalog. Some error messages may indicate the accompanying TimesTen error code if appropriate.
Fatal errors are those that make the database inaccessible until after error recovery. When a fatal error occurs, all database connections are required to disconnect in order to avoid out-of-memory conditions. No further operations may complete. Shared memory from the old TimesTen instance will not be freed until all active connections at the time of the error have disconnected.
Fatal errors in OCI are indicated by the Oracle Database error code ORA-03135
or ORA-00600
. Error handling for these errors should be different from standard error handling. In particular, the application error-handling code should have a disconnect from the database.
The OCI diagnostic framework installs signal handlers that may impact any signal handling that you use in your application. You can disable OCI signal handling by setting DIAG_SIGHANDLER_ENABLED=FALSE
in the sqlnet.ora
file. Refer to "Fault Diagnosability in OCI" in Oracle Call Interface Programmer's Guide for information.
This section covers the following topics for developers using TimesTen OCI:
In OCI, a prepare call is expected to be a lightweight operation performed on the client. To allow TimesTen to be consistent with this expectation, and to avoid unwanted round trips between client and server, the TimesTen client library implementation of SQLPrepare
performs what is referred to as a deferred prepare, where the request is not sent to the server until required. See "TimesTen deferred prepare".
This section discusses features relating to binding parameters into SQL or PL/SQL from an OCI application:
"Binding duplicate parameters in SQL statements" discusses the two supported modes for binding duplicate parameters in a SQL statement, either the Oracle mode or the traditional TimesTen mode. As in that section, consider the following query. Note that in TimesTen OCI, only the Oracle mode is supported.
SELECT * FROM employees WHERE employee_id < :a AND manager_id > :a AND salary < :b;
In OCI, as in the Oracle mode in general, two occurrences of parameter a
are considered to be separate parameters. However, OCI allows both occurrences of a
to be bound with a single call to OCIBindByPos()
:
OCIBindByPos(..., 1, ...); /* both occurrences of :a */ OCIBindByPos(..., 3, ...); /* occurrence of :b */
Alternatively, OCI also allows the two occurrences of a
to be bound separately:
OCIBindByPos(..., 1, ...); /* first occurrence of :a */ OCIBindByPos(..., 2, ...); /* second occurrence of :a */ OCIBindByPos(..., 3, ...); /* occurrence of :b */
Note that in both cases, parameter b
is considered to be in position 3.
Note: OCI also allows parameters to be bound by name, rather than by position, usingOCIBindByName() . |
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 application. This enables arrays of data to be passed efficiently between an application and the database.
An associative array is a set of key-value pairs. In TimesTen, for associative array binding (but not for use of associative arrays only within PL/SQL), the keys, or indexes, must be integers (BINARY_INTEGER
or PLS_INTEGER
). The values must be simple scalar values of the same data type. For example, there could be an array of department managers indexed by department numbers. Indexes are stored in sort order, not creation order.
You can declare an associative array type and then an associative array from PL/SQL as in the following example (note the INDEX BY
):
declare TYPE VARCHARARRTYP IS TABLE OF VARCHAR2(30) INDEX BY BINARY_INTEGER; x VARCHARARRTYP; ...
For Pro*C/C++, see "Associative array bindings in TimesTen Pro*C/C++".
For related information, see "Using associative array binds from applications" in Oracle TimesTen In-Memory Database PL/SQL Developer's Guide.
Notes: Note the following restrictions in TimesTen:
|
TimesTen supports associative array binds in OCI by supporting the maxarr_len
and *curelep
parameters of the OCIBindByName()
and OCIBindByPos()
functions. These parameters are used to indicate that the binding is for an associative array.
The complete calling sequences for those functions are as follows:
sword OCIBindByName ( OCIStmt *stmtp, OCIBind **bindpp, OCIError *errhp, const OraText *placeholder, sb4 placeh_len, void *valuep, sb4 value_sz, ub2 dty, void *indp, ub2 *alenp, ub2 *rcodep, ub4 maxarr_len, ub4 *curelep, ub4 mode ); sword OCIBindByPos ( OCIStmt *stmtp, OCIBind **bindpp, OCIError *errhp, ub4 position, void *valuep, sb4 value_sz, ub2 dty, void *indp, ub2 *alenp, ub2 *rcodep, ub4 maxarr_len, ub4 *curelep, ub4 mode );
The maxarr_len
and *curelep
parameters are used as follows when you bind an associative array. (They should be set to 0 if you are not binding an associative array.)
maxarr_len
: This is an input parameter indicating the maximum array length. This is the maximum number of elements that the associative array can accommodate.
*curelep
: This is an input/output parameter indicating the current array length. It is a pointer to the actual number of elements in the associative array before and after statement execution.
For additional information about these functions, see "OCIBindByName()" and "OCIBindByPos()" in Oracle Call Interface Programmer's Guide.
Note: In TimesTen, theOCIBindDynamic() function and the OCI_DATA_AT_EXEC mode setting for OCIBindByName() and OCIBindByPos() are not supported. (In Oracle Database, OCIBindDynamic() can be used to register user-defined callback functions to provide or receive data in "at exec" mode to set up additional bind attributes at execution time.) |
In Example 3-1, an OCI application binds an integer array and a character array to corresponding OUT
associative arrays in a PL/SQL procedure.
Example 3-1 Binding to an associative array from OCI
Assume the following SQL setup.
DROP TABLE FOO; CREATE TABLE FOO (CNUM INTEGER, CVC2 VARCHAR2(20)); INSERT INTO FOO VALUES ( null, 'VARCHAR 1'); INSERT INTO FOO VALUES (-102, null); INSERT INTO FOO VALUES ( 103, 'VARCHAR 3'); INSERT INTO FOO VALUES (-104, 'VARCHAR 4'); INSERT INTO FOO VALUES ( 105, 'VARCHAR 5'); INSERT INTO FOO VALUES ( 106, 'VARCHAR 6'); INSERT INTO FOO VALUES ( 107, 'VARCHAR 7'); INSERT INTO FOO VALUES ( 108, 'VARCHAR 8'); COMMIT;
Assume the following PL/SQL package definition. This has the INTEGER
associative array type NUMARRTYP
and the VARCHAR2
associative array type VCHARRTYP
, used for output associative arrays c1
and c2
, respectively, in the definition of procedure P1
.
CREATE OR REPLACE PACKAGE PKG1 AS TYPE NUMARRTYP IS TABLE OF INTEGER INDEX BY BINARY_INTEGER; TYPE VCHARRTYP IS TABLE OF VARCHAR2(20) INDEX BY BINARY_INTEGER; PROCEDURE P1(c1 OUT NUMARRTYP,c2 OUT VCHARRTYP); END PKG1; / CREATE OR REPLACE PACKAGE BODY PKG1 AS CURSOR CUR1 IS SELECT CNUM, CVC2 FROM FOO; PROCEDURE P1(c1 OUT NUMARRTYP,c2 OUT VCHARRTYP) IS BEGIN IF NOT CUR1%ISOPEN THEN OPEN CUR1; END IF; FOR i IN 1..8 LOOP FETCH CUR1 INTO c1(i), c2(i); IF CUR1%NOTFOUND THEN CLOSE CUR1; EXIT; END IF; END LOOP; END P1; END PKG1;
The following OCI program calls PKG1.P1
, binds arrays to the P1
output associative arrays, and prints the contents of those associative arrays. Note in particular the OCIBindByName()
function calls to do the binding.
static OCIEnv *envhp; static OCIServer *srvhp; static OCISvcCtx *svchp; static OCIError *errhp; static OCISession *authp; static OCIStmt *stmthp; static OCIBind *bndhp[MAXCOLS]; static OCIBind *dfnhp[MAXCOLS]; STATICF VOID outbnd_1() { int i; int num[MAXROWS]; char* vch[MAXROWS][20]; unsigned int numcnt = 5; unsigned int vchcnt = 5; unsigned short alen_num[MAXROWS]; unsigned short alen_vch[MAXROWS]; unsigned short rc_num[MAXROWS]; unsigned short rc_vch[MAXROWS]; short indp_num[MAXROWS]; short indp_vch[MAXROWS]; /* Assume the process is connected and srvhp, svchp, errhp, authp, and stmthp are all allocated/initialized/etc. */ char *sqlstmt = (char *)"BEGIN PKG1.P1(:c1, :c2); END; "; for (i = 0; i < MAXROWS; i++) { alen_num[i] = 0; alen_vch[i] = 0; rc_num[i] = 0; rc_vch[i] = 0; indp_num[i] = 0; indp_vch[i] = 0; } DISCARD printf("Running outbnd_1.\n"); DISCARD printf("\n----> %s\n", sqlstmt); checkerr(errhp, OCIStmtPrepare(stmthp, errhp, sqlstmt, (unsigned int)strlen((char *)sqlstmt), (unsigned int) OCI_NTV_SYNTAX, (unsigned int) OCI_DEFAULT)); bndhp[0] = 0; bndhp[1] = 0; checkerr(errhp, OCIBindByName(stmthp, &bndhp[0], errhp, (char *) ":c1", (sb4) strlen((char *) ":c1"), (dvoid *) &num[0], (sb4) sizeof(num[0]), SQLT_INT, (dvoid *) &indp_num[0], (unsigned short *) &alen_num[0], (unsigned short *) &rc_num[0], (unsigned int) MAXROWS, (unsigned int *) &numcnt, (unsigned int) OCI_DEFAULT)); checkerr(errhp, OCIBindByName(stmthp, &bndhp[1], errhp, (char *) ":c2", (sb4) strlen((char *) ":c2"), (dvoid *) vch[0], (sb4) sizeof(vch[0]), SQLT_CHR, (dvoid *) &indp_vch[0], (unsigned short *) &alen_vch[0], (unsigned short *) &rc_vch[0], (unsigned int) MAXROWS, (unsigned int *) &vchcnt, (unsigned int) OCI_DEFAULT)); DISCARD printf("\nTo execute the PL/SQL statement.\n"); checkerr(errhp, OCIStmtExecute(svchp, stmthp, errhp, (unsigned int) 1, (unsigned int) 0, (const OCISnapshot*) 0, (OCISnapshot*) 0, (unsigned int) OCI_DEFAULT)); DISCARD printf("\nHere are the results:\n\n"); DISCARD printf("Column 1, INTEGER: \n"); for (i = 0; i < numcnt; i++) { if (indp_num[i] == -1) DISCARD printf("-NULL- "); else DISCARD printf("%5d, ", num[i]); DISCARD printf("ind = %d, len = %d, rc = %d\n", indp_num[i], alen_num[i], rc_num[i]); } DISCARD printf("\nColumn 2, VARCHAR2(20): \n"); for (i = 0; i < vchcnt; i++) { if (indp_vch[i] == -1) DISCARD printf("-NULL- "); else DISCARD printf("%.*s, ", alen_vch[i], vch[i]); DISCARD printf("ind = %d, len = %d, rc = %d\n", indp_vch[i], alen_vch[i], rc_vch[i]); } DISCARD printf("\nDone\n"); return; }
Note: Thealen_* arrays are arrays of lengths; the rc_* arrays are arrays of return codes; the indp_* arrays are arrays of indicators. |
This section discusses TimesTen OCI features related using the IMDB Cache:
Specifying the Oracle Database password in OCI for IMDB Cache
Determining the number of cache groups affected by an action
To use IMDB Cache, there must be a cache user in the TimesTen database with the same name as an Oracle Database user who can select from and update the cached Oracle Database tables. This Oracle Database user, for example, can be the cache administration user or a schema user. The password of the TimesTen cache user can be different from the password of the Oracle Database user with the same name. See "Setting Up a Caching Infrastructure" in Oracle In-Memory Database Cache User's Guide for details.
For use of OCI with the IMDB Cache, TimesTen allows you to pass the Oracle Database user's password through OCI by appending it to the password field in an OCILogon()
or OCILogon2()
call when you log in to TimesTen. Use the attribute OraclePWD
in the connect string, such as in the following example:
text *cacheuser = (text *)"cacheuser1"; text *cachepwds = (text *)"ttpwd;OraclePWD=orclpwd"; text *ttdbname = (text *)"tt_tnsname"; .... OCILogon2(envhp, errhp, &svchp, (text *)cacheuser, (ub4)strlen(cacheuser), (text *)cachepwds, (ub4)strlen(cachepwds), (text *)ttdbname, (ub4)strlen(ttdbname), OCI_DEFAULT));
You must always specify OraclePWD
, even if the Oracle Database user's password is the same as the TimesTen user's password.
Note the following for the example:
The name of the TimesTen cache user, as well as the name of the Oracle Database user who can access the cached Oracle Database tables, is cacheuser1
.
The password of the TimesTen cache user is ttpwd
.
The password of the Oracle Database user is orclpwd
.
The TNS name of the TimesTen database being connected to is tt_tnsname
.
The Oracle database is specified through the TimesTen OracleNetServiceName
general connection attribute in the sys.odbc.ini
or user odbc.ini
file.
Alternatively, instead of using a TNS name, you could use easy connect syntax or the TWO_TASK
or LOCAL
environment variable, as discussed in preceding sections.
In TimesTen OCI, following the execution of a FLUSH CACHE GROUP
, LOAD CACHE GROUP
, REFRESH CACHE GROUP
, or UNLOAD CACHE GROUP
statement, the OCI Function OCIAttrGet()
with the OCI_ATTR_ROW_COUNT
argument returns the number of cache instances that were flushed, loaded, refreshed, or unloaded.
For related information, see "Determining the number of cache instances affected by an operation" in the Oracle In-Memory Database Cache User's Guide.
TimesTen supports LOBs (large objects). This includes CLOBs (character LOBs), NCLOBs (national character LOBs), and BLOBs (binary LOBs).
See "Working with LOBs". That section is ODBC-oriented but also provides some general overview of LOBs, differences between TimesTen and Oracle Database LOBs, and LOB programming interfaces.
This section focuses on LOB locators, temporary LOBs, and OCI LOB APIs and features.
See "LOB data types" in Oracle TimesTen In-Memory Database SQL Reference for additional information about LOBs in TimesTen.
For complete information about LOBs and how to use them in OCI, refer to "LOB and BFILE Operations" in Oracle Call Interface Programmer's Guide, keeping in mind that TimesTen does not support BFILEs, SecureFiles, array reads and writes for LOBs, or callback functions for LOBs.
The following topics are covered here for OCI:
Note: The LOB piecewise data interface is not applicable to OCI applications in TimesTen. (You can, however, manipulate LOB data in pieces through features of the LOB locator interface.) |
OCI provides the LOB locator interface, where a LOB consists of a LOB locator and a LOB value. The locator acts as a handle to the value. When an application selects a LOB from the database, it receives a locator. When it updates the LOB, it does so through the locator. And when it passes a LOB as a parameter, it is passing the locator, not the actual value. See "Using the LOB locator interface in OCI". (Note that in OCI it is also possible to use the simple data interface, which does not involve a locator. See "Using the LOB simple data interface in OCI".)
To update a LOB, your transaction must have an exclusive lock on the row containing the LOB. You can accomplish this by selec ting 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 temporary LOB exists only within an application, and in TimesTen OCI has a lifetime no longer than the transaction in which it was created (as is the case with the lifetime of any LOB locator in TimesTen). You can think of a temporary LOB as a scratch area for LOB data.
An OCI application can instantiate a temporary LOB explicitly, for use within the application, through the appropriate API. (See "Using the LOB locator interface in OCI".) 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 and an OCI application would receive a locator for the temporary LOB.
Temporary LOBs are stored in the TimesTen temporary data partition.
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.
Also see "Differences between TimesTen LOBs and Oracle Database LOBs".
The simple data interface enables applications to access LOB data by binding and defining, as with other scalar data types. The application can use a LOB type that is compatible with the corresponding variable type. Use OCIStmtPrepare()
to prepare a statement. For binding parameters, use OCIBindByName()
or OCIBindByPos()
. For defining result columns, use OCIDefineByPos()
.
For example, an OCI application can bind a CLOB parameter by calling OCIBindByName()
with a data type of SQLT_CHR
. Use OCIStmtExecute()
to execute the statement. For an NCLOB parameter, use data type SQLT_CHR
and set the OCI csform
attribute (OCI_ATTR_CHARSET_FORM
) to SQLCS_NCHAR
. For a BLOB parameter, you can use data type SQLT_BIN
.
Use of the simple data interface through OCI is shown in the following examples.
Note: The simple data interface, throughOCIBindByName() , OCIBindByPos() , or OCIDefineByPos() , limits bind sizes to 64 KB. |
Example 3-2 Example table and variables
For examples that follow, assume the table and variables shown here.
person(ssn number, resume clob) OCIEnv *envhp; OCIServer *srvhp; OCISvcCtx *svchp; OCIError *errhp; OCISession *authp; OCIStmt *stmthp; /* Bind Handles */ OCIBind *bndp1 = (OCIBind *) NULL; OCIBind *bndp2 = (OCIBind *) NULL; /* Define Handles */ OCIDefine *defnp1 = (OCIDefine *) NULL; OCIDefine *defnp2 = (OCIDefine *) NULL; #define DATA_SIZE 50 #define PIECE_SIZE 10 #define NPIECE (DATA_SIZE/PIECE_SIZE) char col2[DATA_SIZE]; char col2Res[DATA_SIZE]; ub2 col2len = DATA_SIZE; sb4 ssn = 123456; ... text *ins_stmt = (text *)"INSERT INTO PERSON VALUES (:1, :2)"; text *sel_stmt = (text *)"SELECT * FROM PERSON_1 ORDER BY SSN"; ...
Example 3-3 Insert LOB data using simple data interface
This example executes an INSERT
statement using the simple data interface in OCI. It uses the table and variables from the preceding Example 3-2, including the INSERT
statement defined through the variable ins_stmt
.
for (i=0;i<DATA_SIZE;i++) col2[i] = 'A'; /* prepare SQL insert statement */ OCIStmtPrepare (stmthp, errhp, ins_stmt, strlen(ins_stmt), OCI_NTV_SYNTAX, OCI_DEFAULT); /* bind parameters 1 and 2 using OCI_DEFAULT (not data-at-exec) */ OCIBindByPos (stmthp, &bndp1, errhp, 1, (dvoid *) &ssn, sizeof(ssn), SQLT_INT, 0, 0, 0, 0, 0, OCI_DEFAULT); OCIBindByPos (stmthp, &bndp2, errhp, 2, (dvoid *) col2, col2len, SQLT_CHR, 0, 0, 0, 0, 0, OCI_DEFAULT); /* execute insert statement */ OCIStmtExecute (svchp, stmthp, errhp, 1, 0, 0, 0, OCI_DEFAULT);
Example 3-4 Select LOB data using simple data interface
This example executes a SELECT
statement using the simple data interface in OCI. It uses the table and variables from the earlier Example 3-2, including the SELECT
statement defined through the variable sel_stmt
.
/* prepare select statement */ OCIStmtPrepare (stmthp, errhp, sel_stmt, strlen(sel_stmt), OCI_NTV_SYNTAX, OCI_DEFAULT); /* define result columns 1 and 2 using OCI_DEFAULT (not data-at-exec) */ OCIDefineByPos (stmthp, &defnp1, errhp, 1, (dvoid*) &ssn, sizeof(ssn), SQLT_INT, 0, 0, 0, OCI_DEFAULT); OCIDefineByPos (stmthp, &defnp2, errhp, 2, (dvoid *) col2Res, sizeof(col2), SQLT_CHR, 0, &col2len, 0, OCI_DEFAULT); /* execute select statement */ OCIStmtExecute (svchp, stmthp, errhp, (ub4)1, (ub4)0, (OCISnapshot *) NULL, (OCISnapshot *) NULL, OCI_DEFAULT)); /* col2Res should now have a DATA_SIZE sized string of 'A's. */
You can use the OCI LOB locator interface to work with either a LOB from the database or a temporary LOB, either piece-by-piece or in whole chunks.
In order to use the LOB locator interface, the application must have a valid LOB locator. For a temporary LOB, this is obtained through the OCILobCreateTemporary()
call, for explicitly created LOBs, or through a SQL statement that results in implicit creation of a temporary LOB (such as SELECT c1 || c2 FROM myclob
). For a persistent LOB, use a SQL statement to obtain the LOB locator from the database. (There are examples later in this section.)
Bind types are SQLT_CLOB
for CLOBs and SQLT_BLOB
for BLOBs. For NCLOBs, use SQLT_CLOB
and also set the OCI csform
attribute (OCI_ATTR_CHARSET_FORM
) to SQLCS_NCHAR
.
Refer to "LOB Functions" in Oracle Call Interface Programmer's Guide for detailed information and additional examples for OCI LOB functions, noting that TimesTen does not support features specifically intended for BFILEs, SecureFiles, array reads and writes for LOBs, or callback functions for LOBs.
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. |
Notes:
|
An OCI application can create a temporary LOB by using the OCILobCreateTemporary()
function, which has an input/output parameter for the LOB locator, after first calling OCIDescriptorAlloc()
to allocate the locator. When you are finished, use OCIDescriptorFree()
to free the allocation for the locator and use OCILobFreeTemporary()
to free the temporary LOB itself.
Important: In TimesTen, creation of a temporary LOB will result in creation of a database transaction if one is not already in progress. To avoid error conditions, you must execute a commit or rollback to close the transaction. |
In TimesTen, any duration supported by Oracle Database (OCI_DURATION_SESSION
, OCI_DURATION_TRANSACTION
, or OCI_DURATION_CALL
) is permissible in the OCILobCreateTemporary()
call; however, in TimesTen the lifetime of the temporary LOB itself will be no longer than the lifetime of the transaction.
Note that the lifetime of a temporary LOB can be shorter than the lifetime of the transaction in the following scenarios:
If OCI_DURATION_CALL
is specified
If the application calls OCILobFreeTemporary()
on the locator before the end of the transaction
If the application calls OCIDurationBegin()
to start a user-specified duration for the temporary LOB, then calls OCIDurationEnd()
before the end of the transaction
Following are examples of some of the OCI LOB functions mentioned above. For details about the use of temporary LOBs and a complete example, see "Temporary LOB Support" in Oracle Call Interface Programmer's Guide.
if (OCIDescriptorAlloc((void*)envhp, (void **)&tblob,(ub4)OCI_DTYPE_LOB, (size_t)0, (void**)0)) { printf("failed in OCIDescriptor Alloc in select_and_createtemp \n"); return OCI_ERROR; } ... if (OCILobCreateTemporary(svchp, errhp, tblob, (ub2)0, SQLCS_IMPLICIT, OCI_TEMP_BLOB, OCI_ATTR_NOCACHE, OCI_DURATION_TRANSACTION)) { (void) printf("FAILED: OCILobCreateTemporary() \n"); return OCI_ERROR; } ... if(OCILobFreeTemporary(svchp,errhp,tblob)) { printf ("FAILED: OCILobFreeTemporary() call \n"); return OCI_ERROR; }
An application typically accesses a LOB from the database by using a SQL statement to obtain or access a LOB locator, then passing the locator to an appropriate API function.
A LOB that has been created using the EMPTY_CLOB()
or EMPTY_BLOB()
SQL function has a valid locator, which an application can then use to insert data into the LOB by selecting it.
Assume the following table definition:
CREATE TABLE clobtable (x NUMBER, y DATE, z VARCHAR2(30), lobcol CLOB);
Prepare an INSERT
statement. For example:
INSERT INTO clobtable ( x, y, z, lobcol ) VALUES ( 81, sysdate, 'giants', EMPTY_CLOB() ) RETURNING lobcol INTO :a;
Or, to initialize the LOB with some data:
INSERT INTO clobtable ( x, y, z, lobcol ) VALUES ( 81, sysdate, 'giants', 'The Giants finally won a World Series' ) RETURNING lobcol INTO :a;
Bind the LOB locator to :a
as shown.
Execute the statement. After execution, the locator will refer to the newly created LOB.
Then the application can use the LOB locator interface to read or write LOB data through the locator.
Alternatively, an application can use a SELECT
statement to access the locator of an existing LOB.
Example 3-5 Select LOB locator using LOB locator interface
This example uses the following table:
person(ssn number, resume clob)
It selects the locator for the LOB column in the PERSON
table.
text *ins_stmt = (text *)"INSERT INTO PERSON VALUES (:1, :2)"; text *sel_stmt = (text *)"SELECT * FROM PERSON WHERE SSN = 123456"; text *ins_empty = (text *)"INSERT INTO PERSON VALUES ( 1, EMPTY_CLOB())"; OCILobLocator *lobp; ub4 amtp = DATA_SIZE; ub4 remainder = DATA_SIZE; ub4 nbytes = PIECE_SIZE; /* Allocate lob locator */ OCIDescriptorAlloc (envhp, &lobp, OCI_DTYPE_LOB, 0, 0); /* Insert an empty locator */ OCIStmtPrepare (stmhp, errhp, ins_empty, strlen(ins_empty), OCI_NTV_SYNTAX, OCI_DEFAULT); OCIStmtExecute (svchp, stmhp, errhp, 1, 0, 0, 0, OCI_DEFAULT); /* Now select the locator */ OCIStmtPrepare (stmhp, errhp, sel_stmt, strlen(sel_stmt), OCI_NTV_SYNTAX, OCI_DEFAULT); /* Call define for the lob column */ OCIDefineByPos (stmthp, &defnp2, errhp, 1, &lobp, 0 , SQLT_CLOB, 0, 0, 0, OCI_DEFAULT); OCIStmtExecute (svchp, stmhp, errhp, 1, 0, 0, 0, OCI_DEFAULT);
An OCI application can use OCILobOpen()
and OCILobClose()
to open and close a LOB. If you do not explicitly open and close a LOB, it will be opened implicitly before a read or write and closed implicitly at the end of the transaction.
An application can use OCILobRead()
or OCILobRead2()
to read LOB data, OCILobWrite()
or OCILobWrite2()
to write LOB data, OCILobWriteAppend()
or OCILobWriteAppend2()
to append LOB data, OCILobErase()
or OCILobErase2()
to erase LOB data, and various other OCI functions to perform a variety of other actions.
For example, consider a CLOB with the content "Hello World!" You can overwrite and append data by calling OCILobWrite()
with an offset of 7 to write "I am a new string". This would result in CLOB content being updated to "Hello I am a new string". Or, to erase data from the original "Hello World!" CLOB, you can call OCILobErase()
with an offset of 7 and an amount (number of characters) of 5, for example, to update the CLOB to "Hello !" (six spaces).
All the OCI LOB locator interface functions are covered in detail in "LOB Functions" in Oracle Call Interface Programmer's Guide.
Notes:
|
Example 3-6 Write and read LOB data using LOB locator interface
This example shows how to write LOB data using the OCI LOB function OCILobWrite()
and how to read data using OCILobRead()
. It uses the table and variables from the preceding Example 3-5.
for (i=0;i<DATA_SIZE;i++) col2[i] = 'A'; /*************** Writing to the LOB *****************/ amt = DATA_SIZE; offset = 1; /* Write contents of col2 buffer into the LOB in a single chunk via locator lobp */ OCILobWrite (svchp, errhp, lobp, &amt, offset, col2, DATA_SIZE, OCI_ONE_PIECE, 0, 0, 0, SQLCS_IMPLICIT); /*************** Reading from the LOB *****************/ /* Get the length of the LOB */ OCILobGetLength (svchp, errhp, lobp, &len); amt = len; /* Read the LOB data in col2Res in a single chunk */ OCILobRead (svchp, errhp, lobp, &amt, offset, col2Res, DATA_SIZE, 0, 0, 0, SQLCS_IMPLICIT);
OCI provides a facility for client-side buffering on a per-LOB basis. It is enabled for a LOB by a call to OCILobEnableBuffering()
and disabled by a call to OCILobDisableBuffering()
.
Enabling buffering for a LOB locator creates a 512 KB write buffer. This size is not configurable. Data written by the application through the LOB locator is buffered. When possible, the client library will satisfy LOB read requests from the buffer as well. An application can flush the buffer by a call to OCILobFlushBuffer()
. Note that buffers are not flushed automatically when they become full, and an attempt to write to the LOB through the locator when the buffer is full will result in an error.
The following restrictions apply when you use client-side buffering:
Buffering is incompatible with the following functions: OCILobAppend()
, OCILobCopy()
, OCILobCopy2()
, OCILobErase()
, OCILobGetLength()
, OCILobTrim()
, OCILobWriteAppend()
, and OCILobWriteAppend2()
.
An application can use OCILobWrite()
or OCILobWrite2()
only to append to the end of a LOB.
LOB data becomes visible to SQL and PL/SQL (server-side) operations only after the application has flushed the buffer.
When a LOB is selected while there are unflushed client-side writes in its buffer, the unflushed data is not included in the select.
To reduce round trips to the server in client/server connections, LOB data can be prefetched from the database and cached on the client side during fetch operations. LOB prefetching in OCI has the same functionality in TimesTen as in Oracle Database.
Configure LOB prefetching through the following OCI attributes. Note that size refers to bytes for BLOBs and to characters for CLOBs or NCLOBs.
OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE
: Use this to enable prefetching and specify the default prefetch size. A value of 0 (default) disables prefetching.
OCI_ATTR_LOBPREFETCH_SIZE
: Set this attribute for a column define handle to specify the prefetch size for the particular LOB column.
OCI_ATTR_LOBPREFETCH_LENGTH
: This attribute can be set TRUE
or FALSE
(default) to prefetch LOB metadata such as LOB length and chunk size.
The OCI_ATTR_DEFAULT_LOBPREFETCH_SIZE
and OCI_ATTR_LOBPREFETCH_LENGTH
settings are independent of each other. You can use LOB data prefetching independently of LOB metadata prefetching.
Refer to "Prefetching of LOB Data, Length, and Chunk Size" in Oracle Call Interface Programmer's Guide for more information and an example.
Note: The above attribute settings are ignored for TimesTen direct connections. |
Passthrough LOBs (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:
You cannot use OCILobCreateTemporary()
to create a passthrough LOB.
In addition to copying from one TimesTen LOB to another TimesTen LOB—such as through OCILobCopy()
, OCILobCopy2()
, or OCILobAppend()
—you can copy from a TimesTen LOB to a passthrough LOB, from a passthrough LOB to a TimesTen LOB, or from one passthrough LOB to another passthrough LOB. Any of these copies the LOB value to the target destination. For example, copying a passthrough LOB to a TimesTen LOB copies the LOB value into the TimesTen database.
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.
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, the size limit applies to the copy.
As with TimesTen local LOBs, a locator for a passthrough LOB does not remain valid past the end of the transaction.
Example 3-7 Copying between TimesTen LOBs and passthrough LOBs
The examples here highlight key functionality in copying between TimesTen LOBs and passthrough LOBs on Oracle Database. After the table and data setup, the first example uses OCILobAppend()
to copy LOB data from Oracle Database to TimesTen and the second example uses OCILobCopy()
to copy LOB data from TimesTen to Oracle Database. (Either call could be used in either case.) Then, for contrast, the third example uses an UPDATE
statement to copy LOB data from Oracle Database to TimesTen and the fourth example uses an INSERT
statement to copy LOB data from TimesTen to Oracle Database.
/* Table and data setup */ call ttoptsetflag(''passthrough'', 3)'; DROP TABLE oratab'; CREATE TABLE oratab (i INT, c CLOB)'; INSERT INTO oratab VALUES (1, ''Copy from Oracle to TimesTen'')'; INSERT INTO oratab VALUES (2, EMPTY_CLOB())'; COMMIT; call ttoptsetflag(''passthrough'', 0)'; DROP TABLE tttab'; CREATE TABLE tttab (i INT, c CLOB)'; INSERT INTO tttab VALUES (1, ''Copy from TimesTen to Oracle'')'; INSERT INTO tttab VALUES (2, EMPTY_CLOB())'; INSERT INTO tttab VALUES (3, NULL)'; COMMIT; /* Table and data setup end */ /* * Below are four OCI pseudocode examples, for copying LOBs between * TimesTen and Oracle using OCI API and INSERT/UPDATE statements. */ /* Init OCI Env */ /* Set the passthrough level to 1 */ OCIStmtPrepare (..., "call ttoptsetflag(''passthrough'', 1)'", ...); OCIStmtExecute (...); /* * 1. Copy a passthrough LOB on Oracle to a TimesTen LOB */ /* Select a passthrough locator on Oracle */ OCIStmtPrepare (..., "SELECT c FROM oratab WHERE i = 1", ...); OCIDefineByPos (..., (dvoid *)&ora_loc_1, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); /* Select a locator on TimesTen for update */ OCIStmtPrepare (..., "SELECT c FROM tttab WHERE i = 2 FOR UPDATE", ...); OCIDefineByPos (..., (dvoid *)&tt_loc_2, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); /* Copy a passthrough LOB on Oracle to a TimesTen LOB */ OCILobAppend(..., tt_loc_2, ora_loc_1); /* * 2. Copy a TimesTen LOB to a passthrough LOB on Oracle */ /* Select a passthrough locator on Oracle for update */ OCIStmtPrepare (..., "SELECT c FROM oratab WHERE i = 2 FOR UPDATE", ...); OCIDefineByPos (..., (dvoid *)&ora_loc_2, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); /* Select a locator on TimesTen */ OCIStmtPrepare (..., "SELECT c FROM tttab WHERE i = 1", ...); OCIDefineByPos (..., (dvoid *)&tt_loc_1, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); /* Copy a passthrough LOB on Oracle to a TimesTen LOB */ OCILobCopy(..., ora_loc_2, tt_loc_1, 28, 1, 1); /* * 3. UPDATE a TimesTen LOB with a passthrough LOB on Oracle */ /* A passthrough LOB, (selected above in case 1) is bound to an UPDATE statement * on TimesTen table */ OCIStmtPrepare (..., "UPDATE tttab SET c = :1 WHERE i = 3", ...); OCIBindByPos (..., (dvoid *)&ora_loc_1, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); /* * 4. INSERT a passthrough table on Oracle with a TimesTen LOB */ /* A TimesTen LOB, (selected above in case 2) is bound to an INSERT statement * on a passthough table on Oracle */ OCIStmtPrepare (..., "INSERT INTO oratab VALUES (3, :1)", ...); OCIBindByPos (..., (dvoid *)&tt_loc_1, 0 , SQLT_CLOB, ...); OCIStmtExecute (...); OCITransCommit (...); /* Cleanup OCI Env */
This is a reference section for TimesTen support of OCI features, covering the following areas:
Table 3-2 lists TimesTen support for OCI calls that are documented for Oracle Database release 11.2.0.2.
Some groups of calls are represented with an asterisk in the name. For example, the calls related to Advanced Queuing, which TimesTen does not support, have names that start with OCIAQ
and are represented in the table as OCIAQ*()
. OCI date functions, which TimesTen does support, are designated by OCIDate*()
.