D Initialization Parameters
The Oracle database initialization parameters in the init.ora file are distinct from gateway initialization parameters. Set the gateway parameters in the initialization parameter file using an agent-specific mechanism, or set them in the Oracle data dictionary using the DBMS_HS package. The gateway initialization parameter file must be available when the gateway is started.
This appendix contains a list of the gateway initialization parameters that can be set for each gateway and their description. It also describes the initialization parameter file syntax. It includes the following sections:
D.1 Initialization Parameter File Syntax
The syntax for the initialization parameter file is as follows:
-
The file is a sequence of commands.
-
Each command should start on a separate line.
-
End of line is considered a command terminator (unless escaped with a backslash).
-
If there is a syntax error in an initialization parameter file, none of the settings take effect.
-
Set the parameter values as follows:
[SET][PRIVATE] parameter=value
Where:
parameteris an initialization parameter name. It is a string of characters starting with a letter and consisting of letters, digits and underscores. Initialization parameter names are case sensitive.valueis the initialization parameter value. It is case sensitive. An initialization parameter value is either:-
A string of characters that does not contain any backslashes, white space or double quotation marks (")
-
A quoted string beginning with a double quotation mark and ending with a double quotation mark. The following can be used inside a quoted string:
-
backslash (\) is the escape character
-
\n inserts a new line
-
\t inserts a tab
-
\" inserts a double quotation mark
-
\\ inserts a backslash
A backslash at the end of the line continues the string on the next line. If a backslash precedes any other character then the backslash is ignored.
-
For example, to enable tracing for an agent, set the
HS_FDS_TRACE_LEVELinitialization parameter as follows:HS_FDS_TRACE_LEVEL=ON
SETandPRIVATEare optional keywords. You cannot use either as an initialization parameter name. Most parameters are needed only as initialization parameters, so you usually do not need to use theSETorPRIVATEkeywords. If you do not specify eitherSETorPRIVATE, the parameter is used only as an initialization parameter for the agent.SETspecifies that, in addition to being used as an initialization parameter, the parameter value is set as an environment variable for the agent process. UseSETfor parameter values that the drivers or non-Oracle system need as environment variables.PRIVATEspecifies that the initialization parameter should be private to the agent and should not be uploaded to the Oracle database. Most initialization parameters should not be private. If, however, you are storing sensitive information like a password in the initialization parameter file, then you may not want it uploaded to the server because the initialization parameters and values are not encrypted when uploaded. Making the initialization parameters private prevents the upload from happening and they do not appear in dynamic performance views. UsePRIVATEfor the initialization parameters only if the parameter value includes sensitive information such as a user name or password.SET PRIVATEspecifies that the parameter value is set as an environment variable for the agent process and is also private (not transferred to the Oracle database, not appearing in dynamic performance views or graphical user interfaces). -
D.2 Oracle Database Gateway for Sybase Initialization Parameters
This section lists all the initialization file parameters that can be set for the Oracle Database Gateway for Sybase. They are as follows:
D.3 Initialization Parameter Description
The following sections describe all the initialization file parameters that can be set for gateways.
D.3.1 HS_CALL_NAME
| Property | Description |
|---|---|
| Default value | None |
| Range of values | Not applicable |
Specifies the remote functions that can be referenced in SQL statements. The value is a list of remote functions and their owners, separated by semicolons, in the following format:
owner_name.function_name
For example:
owner1.A1;owner2.A2;owner3.A3
If an owner name is not specified for a remote function, the default owner name becomes the user name used to connect to the remote database (specified when the Heterogeneous Services database link is created or taken from user session if not specified in the DB link).
The entries for the owner names and the function names are case sensitive.
D.3.2 HS_DB_DOMAIN
| Property | Description |
|---|---|
| Default value | WORLD |
| Range of values | 1 to 199 characters |
Specifies a unique network sub-address for a non-Oracle system. The HS_DB_DOMAIN initialization parameter is similar to the DB_DOMAIN initialization parameter, described in the Oracle Database Reference. The HS_DB_DOMAIN initialization parameter is required if you use the Oracle Names server. The HS_DB_NAME and HS_DB_DOMAIN initialization parameters define the global name of the non-Oracle system.
|
Note: TheHS_DB_NAME and HS_DB_DOMAIN initialization parameters must combine to form a unique address in a cooperative server environment. |
D.3.3 HS_DB_INTERNAL_NAME
| Property | Description |
|---|---|
| Default value | 01010101 |
| Range of values | 1 to 16 hexadecimal characters |
Specifies a unique hexadecimal number identifying the instance to which the Heterogeneous Services agent is connected. This parameter's value is used as part of a transaction ID when global name services are activated. Specifying a nonunique number can cause problems when two-phase commit recovery actions are necessary for a transaction.
D.3.4 HS_DB_NAME
| Property | Description |
|---|---|
| Default value | HO |
| Range of values | 1 to 8 characters |
Specifies a unique alphanumeric name for the data store given to the non-Oracle system. This name identifies the non-Oracle system within the cooperative server environment. The HS_DB_NAME and HS_DB_DOMAIN initialization parameters define the global name of the non-Oracle system.
D.3.5 HS_DESCRIBE_CACHE_HWM
| Property | Description |
|---|---|
| Default value | 100 |
| Range of values | 1 to 4000 |
Specifies the maximum number of entries in the describe cache used by Heterogeneous Services. This limit is known as the describe cache high water mark. The cache contains descriptions of the mapped tables that Heterogeneous Services reuses so that it does not have to re-access the non-Oracle data store.
If you are accessing many mapped tables, increase the high water mark to improve performance. Increasing the high water mark improves performance at the cost of memory usage.
D.3.6 HS_LANGUAGE
| Property | Description |
|---|---|
| Default value | System-specific |
| Range of values | Any valid language name (up to 255 characters) |
Provides Heterogeneous Services with character set, language, and territory information of the non-Oracle data source. The value must use the following format:
language[_territory.character_set]
|
Note: The globalization support initialization parameters affect error messages, the data for the SQL Service, and parameters in distributed external procedures. |
D.3.6.1 Character Sets
Ideally, the character sets of the Oracle database and the non-Oracle data source are the same. In almost all cases, HS_LANGUAGE should be set exactly the same as Oracle database character set for optimal character set mapping and performance. If they are not the same, Heterogeneous Services attempts to translate the character set of the non-Oracle data source to the Oracle database character set, and back again. The translation can degrade performance. In some cases, Heterogeneous Services cannot translate a character from one character set to another.
|
Note: The specified character set must be a superset of the operating system character set on the platform where the agent is installed. |
As more Oracle databases and non-Oracle databases use Unicode as database character sets, it is preferable to also run the gateway in Unicode character set. To do so, you must set HS_LANGUAGE=AL32UTF8. However, when the gateway runs on Windows, the Microsoft ODBC Driver Manager interface can exchange data only in the double-byte character set, UCS2. This results in extra ratio expansion of described buffer and column sizes. Refer to HS_FDS_REMOTE_DB_CHARSET for instruction on how to adjust to correct sizes.
D.3.6.2 Language
The language component of the HS_LANGUAGE initialization parameter determines:
-
Day and month names of dates
-
AD, BC, PM, and AM symbols for date and time
-
Default sorting mechanism
Note that Oracle does not determine the language for error messages for the generic Heterogeneous Services messages (ORA-25000 through ORA-28000). These are controlled by the session settings in the Oracle database.
D.3.6.3 Territory
The territory clause specifies the conventions for day and week numbering, default date format, decimal character and group separator, and ISO and local currency symbols. Note that the level of globalization support between the Oracle database and the non-Oracle data source depends on how the gateway is implemented.
D.3.7 HS_LONG_PIECE_TRANSFER_SIZE
| Property | Description |
|---|---|
| Default value | 64 KB |
| Range of values | Any value up to 2 GB |
Sets the size of the piece of LONG data being transferred. A smaller piece size means less memory requirement, but more round-trips to fetch all the data. A larger piece size means fewer round-trips, but more of a memory requirement to store the intermediate pieces internally. Thus, the initialization parameter can be used to tune a system for the best performance, with the best trade-off between round-trips and memory requirements, and network latency or response time.
D.3.8 HS_OPEN_CURSORS
| Property | Description |
|---|---|
| Default value | 50 |
| Range of values | 1 to the value of Oracle's OPEN_CURSORS initialization parameter |
Defines the maximum number of cursors that can be open on one connection to a non-Oracle system instance.
The value never exceeds the number of open cursors in the Oracle database. Therefore, setting the same value as the OPEN_CURSORS initialization parameter in the Oracle database is recommended.
D.3.9 HS_RPC_FETCH_REBLOCKING
| Property | Description |
|---|---|
| Default value | ON |
| Range of values | OFF or ON |
Controls whether Heterogeneous Services attempts to optimize performance of data transfer between the Oracle database and the Heterogeneous Services agent connected to the non-Oracle data store.
The following values are possible:
-
OFFdisables reblocking of fetched data so that data is immediately sent from agent to server. -
ONenables reblocking, which means that data fetched from the non-Oracle system is buffered in the agent and is not sent to the Oracle database until the amount of fetched data is equal or higher than the value ofHS_RPC_FETCH_SIZEinitialization parameter. However, any buffered data is returned immediately when a fetch indicates that no more data exists or when the non-Oracle system reports an error.
D.3.10 HS_RPC_FETCH_SIZE
| Property | Description |
|---|---|
| Default value | 50000 |
| Range of values | 1 to 10000000 |
Tunes internal data buffering to optimize the data transfer rate between the server and the agent process.
Increasing the value can reduce the number of network round-trips needed to transfer a given amount of data, but also tends to increase data bandwidth and to reduce latency as measured between issuing a query and completion of all fetches for the query. Nevertheless, increasing the fetch size can increase latency for the initial fetch results of a query, because the first fetch results are not transmitted until additional data is available.
D.3.11 HS_TIME_ZONE
| Property | Description |
|---|---|
| Default value for '[+|-]hh:mm' | Derived from the NLS_TERRITORY initialization parameter |
| Range of values for '[+|-]hh:mm' | Any valid datetime format mask |
Specifies the default local time zone displacement for the current SQL session. The format mask, [+|-]hh:mm, is specified to indicate the hours and minutes before or after UTC (Coordinated Universal Time—formerly Greenwich Mean Time). For example:
HS_TIME_ZONE = [+ | -] hh:mm
D.3.12 HS_TRANSACTION_MODEL
| Property | Description |
|---|---|
| Default Value | COMMIT_CONFIRM |
| Range of Values | COMMIT_CONFIRM, READ_ONLY, SINGLE_SITE, READ_ONLY_AUTOCOMMIT, SINGLE_SITE_AUTOCOMMIT |
Specifies the type of transaction model that is used when the non-Oracle database is updated by a transaction.
The following values are possible:
-
COMMIT_CONFIRMprovides read and write access to the non-Oracle database and allows the gateway to be part of a distributed update. To use the commit-confirm model, the following items must be created in the non-Oracle database:-
Transaction log table. The default table name is
HS_TRANSACTION_LOG. A different name can be set using theHS_FDS_TRANSACTION_LOGparameter. The transaction log table must be grantedSELECT,DELETE, andINSERTprivileges set to public. -
Recovery account. The account name is assigned with the
HS_FDS_RECOVERY_ACCOUNTparameter. -
Recovery account password. The password is assigned with the
HS_FDS_RECOVERY_PWDparameter.
-
-
READ_ONLYprovides read access to the non-Oracle database. -
SINGLE_SITEprovides read and write access to the non-Oracle database. However, the gateway cannot participate in distributed updates. -
READ_ONLY_AUTOCOMMITprovides read only access to the non-Oracle database that does not use logging. -
SINGLE_SITE_AUTOCOMMITprovides read and write access to the non-Oracle database without logging. The gateway cannot participate in distributed updates. Moreover, any update to the non-Oracle database is committed immediately.
D.3.13 IFILE
| Property | Description |
|---|---|
| Default value | None |
| Range of values | Valid parameter file names |
Use the IFILE initialization parameter to embed another initialization file within the current initialization file. The value should be an absolute path and should not contain environment variables. The three levels of nesting limit do not apply.
D.3.14 HS_FDS_CONNECT_INFO
| Property | Description |
|---|---|
| Default Value | None |
| Range of Values | Not applicable |
HS_FDS_CONNECT_INFO that describes the connection to the non-Oracle system.
The default initialization parameter file already has an entry for this parameter. The syntax for HS_FDS_CONNECT_INFO for the gateway is as follows:
HS_FDS_CONNECT_INFO=host_name:port_number/database_name
where, host_name is the host name or IP address of the machine hosting the Sybase database, port_number is the port number of the Sybase database server, and database_name is the Sybase database name.
This release supports IPv6 format, so you can enter IPv6 format in place of hostname, but you need to wrap square brackets around the IPv6 specification.
For example,
HS_FDS_CONNECT_INFO=[2001:0db8:20c:f1ff:fec6:38af]:port_number/…
D.3.15 HS_FDS_PROC_IS_FUNC
| Property | Description |
|---|---|
| Default Value | FALSE |
| Range of Values | TRUE, FALSE |
Enables return values from functions. By default, all stored procedures and functions do not return a return value to the user.
|
Note: If you set this initialization parameter, you must change the syntax of the procedure execute statement for all existing stored procedures to handle return values. |
D.3.16 HS_FDS_RECOVERY_ACCOUNT
| Property | Description |
|---|---|
| Default Value | RECOVER |
| Range of values | Any valid user ID |
Specifies the name of the recovery account used for the commit-confirm transaction model. An account with user name and password must be set up at the non-Oracle system. For more information about the commit-confirm model, see the HS_TRANSACTION_MODEL parameter.
The name of the recovery account is case sensitive.
D.3.17 HS_FDS_RECOVERY_PWD
| Property | Description |
|---|---|
| Default Value | RECOVER |
| Range of values | Any valid password |
Specifies the password of the recovery account used for the commit-confirm transaction model set up at the non-Oracle system. For more information about the commit-confirm model, see the HS_TRANSACTION_MODEL parameter.
The name of the password of the recovery account is case sensitive.
D.3.18 HS_FDS_RESULTSET_SUPPORT
| Property | Description |
|---|---|
| Default Value | FALSE |
| Range of Values | TRUE, FALSE |
Enables result sets to be returned from stored procedures. By default, all stored procedures do not return a result set to the user.
|
Note: If you set this initialization parameter, you must do the following:
|
D.3.19 HS_FDS_TRACE_LEVEL
| Property | Description |
|---|---|
| Default Value | OFF |
| Range of values | OFF, ON, DEBUG |
Specifies whether error tracing is turned on or off for gateway connectivity.
The following values are valid:
-
OFFdisables the tracing of error messages. -
ONenables the tracing of error messages that occur when you encounter problems. The results are written by default to a gateway log file in LOG directory where the gateway is installed. -
DEBUGenables the tracing of detailed error messages that can be used for debugging.
D.3.20 HS_FDS_TRANSACTION_LOG
| Property | Description |
|---|---|
| Default Value | HS_TRANSACTION_LOG |
| Range of Values | Any valid table name |
Specifies the name of the table created in the non-Oracle system for logging transactions. For more information about the transaction model, see the HS_TRANSACTION_MODEL parameter.
D.3.21 HS_FDS_FETCH_ROWS
| Property | Description |
|---|---|
| Default Value | 100 |
| Range of Values | Any integer between 1 and 1000 |
| Syntax | HS_FDS_FETCH_ROWS=num |
HS_FDS_FETCH_ROWS specifies the fetch array size. This is the number of rows to be fetched from the non-Oracle database and to return to Oracle database at one time. This parameter will be affected by the HS_RPC_FETCH_SIZE and HS_RPC_FETCH_REBLOCKING parameters.
D.3.22 HS_FDS_QUOTE_IDENTIFIER
| Property | Description |
|---|---|
| Default Value | TRUE for Sybase |
| Range of Values | TRUE | FALSE |
| Syntax | HS_FDS_QUOTE_IDENTIFIER = { TRUE | FALSE } |
HS_FDS_QUOTE_IDENTIFIER overrides the target's ability to support quote identifier depending on the value provided. The default value is TRUE for Sybase.
D.3.23 HS_IDLE_TIMEOUT
| Property | Description |
|---|---|
| Default Value | 0 (no timeout) |
| Range of Values | 0-9999 (minutes) |
| Syntax | HS_IDLE_TIMEOUT=num |
This feature is only available for Oracle Net TCP protocol. When there is no activity for a connected gateway session for this specified time period, the gateway session would be terminated automatically with pending update (if any) rolled back.
D.3.24 HS_NLS_LENGTH_SEMANTICS
| Property | Description |
|---|---|
| Default Value | BYTE |
| Range of Values | BYTE | CHAR |
| Syntax | HS_NLS_LENGTH_SEMANTICS = { BYTE | CHAR } |
This release of gateway has Character Semantics functionality equivalent to the Oracle Database Character Semantics, that is, NLS_LENGTH_SEMANTICS. When HS_NLS_LENGTH_SEMANTICS is set to CHAR, the (VAR)CHAR columns of Sybase database are to be interpreted as having CHAR semantics. The only situation the gateway does not honor the HS_NLS_LENGTH_SEMANTICS=CHAR setting is when both Oracle database and the gateway are on the same multi-byte character set.
D.3.25 HS_KEEP_REMOTE_COLUMN_SIZE
| Property | Description |
|---|---|
| Default Value | OFF |
| Range of Values | OFF | LOCAL | REMOTE | ALL |
| Syntax | HS_KEEP_REMOTE_COLUMN_SIZE = OFF | LOCAL |REMOTE | ALL |
| Parameter type | String |
HS_KEEP_REMOTE_COLUMN_SIZE specifies whether to suppress ratio expansion when computing the length of (VAR)CHAR datatypes during data conversion from the non-Oracle database to the gateway, and then to the Oracle database. When it is set to REMOTE, the expansion is suppressed between the non-Oracle database and the gateway. When it is set to LOCAL, the expansion is suppressed between the gateway and the Oracle database. When it is set to ALL, the expansion is suppressed from the non-Oracle database to the Oracle database.
When the parameter is set, the expansion is suppressed when reporting the remote column size, calculating the implicit resulting buffer size, and instantiating in the local Oracle database. This has effect only for remote column size from non-Oracle database to Oracle database. If the gateway runs on Windows and HS_LANGUAGE=AL32UTF8, then you must not specify this parameter, as it would influence other ratio related parameter operation. It has no effect for calculating ratio for data moving from Oracle database to non-Oracle database through gateway during INSERT, UPDATE, or DELETE.
D.3.26 HS_FDS_REMOTE_DB_CHARSET
| Property | Description |
|---|---|
| Default Value | None |
| Range of values | Not applicable |
| Syntax | HS_FDS_REMOTE_DB_CHARSET |
This parameter is valid only when HS_LANGUAGE is set to AL32UTF8 and the gateway runs on Windows. As more Oracle databases and non-Oracle databases use Unicode as database character sets, it is preferable to also run the gateway in Unicode character set. To do so, you must set HS_LANGUAGE=AL32UTF8. However, when the gateway runs on Windows, the Microsoft ODBC Driver Manager interface can exchange data only in the double-byte character set, UCS2. This results in extra ratio expansion of described buffer and column sizes. To compensate, the gateway can re-adjust the column size if HS_FDS_REMOTE_DB_CHARSET is set to the corresponding non-Oracle database character set. For example, HS_FDS_REMOTE_DB_CHARSET=KO16KSC5601.
D.3.27 HS_FDS_SUPPORT_STATISTICS
| Property | Description |
|---|---|
| Default Value | TRUE |
| Range of values | {TRUE|FALSE} |
| Syntax | HS_FDS_SUPPORT_STATISTICS= {TRUE|FALSE} |
We gather statistics from the non-Oracle database by default. You can choose to disable the gathering of remote database statistics by setting the HS_FDS_SUPPORT_STATISTICS parameter to FALSE.
D.3.28 HS_FDS_RSET_RETURN_ROWCOUNT
| Property | Description |
|---|---|
| Default Value | FALSE |
| Range of values | {TRUE|FALSE} |
| Syntax | HS_FDS_RSET_RETURN_ROWCOUNT= {TRUE|FALSE} |
When set to TRUE, the gateway returns the row counts of DML statements that are executed inside a stored procedure. The row count is returned as a single row, single column result set of type signed integer.
When set to FALSE, the gateway skips the row counts of DML statements that are executed inside a stored procedure. This is the default behavior, and it is the behavior of 11.1 and older gateways.
D.3.29 HS_FDS_SQLLEN_INTERPRETATION
| Property | Description |
|---|---|
| Default Value | 64 |
| Range of values | {64|32} |
| Syntax | HS_FDS_SQLLEN_INTERPRETATION= {64|32} |
This parameter is only valid for 64 bit platforms. ODBC standard specifies SQLLEN (of internal ODBC construct) being 64 bit on 64 bit platforms, but some ODBC driver managers and drivers violate this convention, and implement it as 32 bit. In order for the gateway to compensate their behavior, you need to specify HS_FDS_SQLLEN_INTERPRETATION=32 if you use these types of driver managers and driver.
Oracle® Database Gateway for Sybase
User's Guide
11g Release 2 (11.2)
E12067-03
January 2012
Oracle Database Gateway for Sybase User's Guide, 11g Release 2 (11.2)
E12067-03
Copyright © 2002, 2012, Oracle and/or its affiliates. All rights reserved.
Primary Author: Maitreyee Chaliha
Contributor: Vira Goorah, Juan Pablo Ahues-Vasquez, Peter Castro, Charles Benet, Peter Wong, and Govind Lakkoju
This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.
The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.
If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:
U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle America, Inc., 500 Oracle Parkway, Redwood City, CA 94065.
This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.
Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.
Intel and Intel Xeon are trademarks or registered trademarks of Intel Corporation. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. AMD, Opteron, the AMD logo, and the AMD Opteron logo are trademarks or registered trademarks of Advanced Micro Devices. UNIX is a registered trademark of The Open Group.
This software or hardware and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.
1 Introduction
This chapter introduces the challenge faced by organizations when running several different database systems. It briefly covers Heterogeneous Services, the technology that the Oracle Database Gateway for Sybase is based on.
To get a good understanding of generic gateway technology, Heterogeneous Services, and how Oracle Database Gateways fit in the picture, reading the Oracle Database Heterogeneous Connectivity User's Guide first is highly recommended.
This chapter contains the following sections:
1.1 Overview
Heterogeneous data access is a problem that affects a lot of companies. A lot of companies run several different database systems. Each of these systems stores data and has a set of applications that run against it. Consolidation of this data in one database system is often hard - in large part because that many of the applications that run against one database may not have an equivalent that runs against another. Until such time as migration to one consolidated database system is made feasible, it is necessary for the various heterogeneous database systems to interoperate.
Oracle Database Gateways provide the ability to transparently access data residing in a non-Oracle system from an Oracle environment. This transparency eliminates the need for application developers to customize their applications to access data from different non-Oracle systems, thus decreasing development efforts and increasing the mobility of the application. Applications can be developed using a consistent Oracle interface for both Oracle and Sybase.
Gateway technology is composed of two parts: a component that has the generic technology to connect to a non-Oracle system, which is common to all the non-Oracle systems, called Heterogeneous Services, and a component that is specific to the non-Oracle system that the gateway connects to. Heterogeneous Services, in conjunction with the Oracle Database Gateway agent, enables transparent access to non-Oracle systems from an Oracle environment.
1.2 Heterogeneous Services Technology
Heterogeneous Services provides the generic technology for connecting to non-Oracle systems. As an integrated component of the database, Heterogeneous Services can exploit features of the database, such as the powerful SQL parsing and distributed optimization capabilities.
Heterogeneous Services extend the Oracle SQL engine to recognize the SQL and procedural capabilities of the remote non-Oracle system and the mappings required to obtain necessary data dictionary information. Heterogeneous Services provides two types of translations: the ability to translate Oracle SQL into the proper dialect of the non-Oracle system as well as data dictionary translations that displays the metadata of the non-Oracle system in the local format. For situations where no translations are available, native SQL can be issued to the non-Oracle system using the pass-through feature of Heterogeneous Services.
Heterogeneous Services also maintains the transaction coordination between Oracle and the remote non-Oracle system, such as providing the two-phase commit protocol to ensure distributed transaction integrity, even for non-Oracle systems that do not natively support two-phase commit.
|
See Also: Oracle Database Heterogeneous Connectivity User's Guide for more information about Heterogeneous Services. |
1.3 Oracle Database Gateways
The capabilities, SQL mappings, data type conversions, and interface to the remote non-Oracle system are contained in the gateway. The gateway interacts with Heterogeneous Services to provide the transparent connectivity between Oracle and non-Oracle systems.
The gateway can be installed on any machine independent of the Oracle or non-Oracle database. It can be the same machine as the Oracle database or on the same machine as the Sybase database or on a third machine as a standalone. Each configuration has its advantages and disadvantages. The issues to consider when determining where to install the gateway are network traffic, operating system platform availability, hardware resources and storage.
B Supported SQL Syntax and Functions
This appendix contains the following sections:
B.1 Supported SQL Statements
With a few exceptions, the gateway provides full support for Oracle DELETE, INSERT, SELECT, and UPDATE statements.
The gateway does not support Oracle data definition language (DDL) statements. No form of the Oracle ALTER, CREATE, DROP, GRANT, or TRUNCATE statements can be used. Instead, for ALTER, CREATE, DROP, and GRANT statements, use the pass-through feature of the gateway if you need to use DDL statements against the Sybase database.
|
Note: TRUNCATE cannot be used in a pass-through statement. |
|
See Also: Oracle Database SQL Language Reference for detailed descriptions of keywords, parameters, and options and the Sybase documentation for details of executing SQL statements in a transaction. |
B.1.1 DELETE
The DELETE statement is fully supported. However, only Oracle functions supported by Sybase can be used.
B.1.2 INSERT
The INSERT statement is fully supported. However, only Oracle functions supported by Sybase can be used.
B.1.3 SELECT
The SELECT statement is fully supported, with these exceptions:
-
CONNECT BYcondition -
NOWAIT -
START WITHcondition -
WHERE CURRENTOF
B.2 Oracle Functions
All functions are evaluated by the Sybase database after the gateway has converted them to Sybase SQL.
B.2.1 Functions Not Supported by Sybase
Oracle SQL functions with no equivalent function in Sybase are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database if the statement is a SELECT statement. That is, the Oracle database performs post-processing of SELECT statements sent to the gateway.
If an unsupported function is used in a DELETE, INSERT, or UPDATE, statement, the following Oracle error occurs:
ORA-02070: database db_link_name does not support function in this context
B.2.2 Functions Supported by Sybase
The gateway translates the following Oracle database functions in SQL statements to their equivalent Sybase functions:
B.2.2.2 Comparison Operators
| Oracle | Sybase |
|---|---|
= | = |
> | > |
< | < |
>= | >= |
<= | <= |
<>, !=, ^= | <>, != |
IS NOT NULL | IS NOT NULL |
IS NULL | IS NULL |
B.2.2.4 String Functions
| Oracle | Sybase |
|---|---|
|| | + (expression1 + expression2) |
ASCII | ASCII |
CHR | CHAR |
INSTR | CHARINDEX |
LENGTH | CHAR_LENGTH |
LOWER | LOWER |
SUBSTR (second argument cannot be a negative number) | SUBSTRING |
UPPER | UPPER |
B.2.2.5 Other Functions
| Oracle | Sybase |
|---|---|
ABS | ABS |
CEIL | CEILING |
COS | COS |
EXP | EXP |
FLOOR | FLOOR |
LN | LOG |
LOG | LOG10 |
MOD | % |
NOT NVL | IS NOT NULL |
NVL | IS NULL |
POWER | POWER |
ROUND | ROUND |
SIN | SIN |
SQRT | SQRT |
TAN | TAN |
Preface
This manual describes the Oracle Database Gateway for Sybase, which enables Oracle client applications to access Sybase data through Structured Query Language (SQL). The gateway, with the Oracle database, creates the appearance that all data resides on a local Oracle database, even though the data can be widely distributed.
This preface covers the following topics:
Audience
This manual is intended for Oracle database administrators who perform the following tasks:
-
Installing and configuring the Oracle Database Gateway for Sybase
-
Diagnosing gateway errors
-
Using the gateway to access Sybase data
Note:
You should understand the fundamentals of Oracle Database Gateways and the UNIX based platform before using this guide to install or administer the gateway.
Documentation Accessibility
For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.
Access to Oracle Support
Oracle customers have access to electronic support through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs if you are hearing impaired.
Related Documents
For more information, see the following documents:
Many of the examples in this book use the sample schemas of the seed database, which is installed by default when you install Oracle. Refer to Oracle Database Sample Schemas for information on how these schemas were created and how you can use them yourself.
Conventions
The following text conventions are used in this document:
| Convention | Meaning |
|---|---|
| boldface | Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary. |
| italic | Italic type indicates book titles, emphasis, or placeholder variables for which you supply particular values. |
monospace | Monospace type indicates commands within a paragraph, URLs, code in examples, text that appears on the screen, or text that you enter. |
Index
A B C D E F G H I K L M N O P R S T U V WA
B
C
- Case rules, 2.7.3.2
- Case studies, 3
- Chained mode, 2.7.1
- CHAR data type, A.1
- character sets
-
- Heterogeneous Services, D.3.6.1
- COMMIT
-
- restrictions, 2.8.3
- Commit point site, 2.8.2
- Comparison operators, B.2.2.2
- CONCAT operator, 2.9.4
- CONNECT BY clause, 2.8.7.2
- COPY command, 2.8.8
- CREATE statement, B.1
- Cursor loops
-
- restrictions, 2.8.3
D
- Data definition language, B.1
- Data dictionary
-
- views, C.1.4
- Data type
-
- BINARY, A.1
- BIT, A.1
- CHAR, A.1
- conversion, 2.7.4.2
- DATE, A.1
- DATETIME, A.1
- DECIMAL, A.1
- FLOAT, A.1
- IMAGE, A.1
- INTEGER, A.1
- LONG, A.1
- LONG RAW, A.1
- MONEY, A.1
- NUMBER, A.1
- NUMERIC, A.1
- RAW, A.1
- REAL, A.1
- SMALL DATETIME, A.1
- SMALL MONEY, A.1
- SMALLINT, A.1
- TEXT, A.1
- TINYINT, A.1
- VARBINARY, 2.9.1, A.1
- VARCHAR, A.1
- VARCHAR2, A.1
- DATE data type, A.1
- DATETIME data type, A.1
- DDL statement, 2.8.5
- DECIMAL data type, A.1
- DELETE statement, 3.9.1, B.1.1, B.2.1
- demonstration build SQL script, 3.3
- Demonstration files, 3.3
- Demonstration tables, 3.5
- Demonstration tables build SQL script, 3.5
- describe cache high water mark
-
- definition, D.3.5
- DROP statement, B.1
E
- Encrypted format login, 2.9.1
- Error messages
-
- error tracing, D.3.19
- Errors
-
- ORA-02070, 2.8.2
- Executing Stored Procedures, 3.12
F
G
- Gateway
- globalization support
-
- Heterogeneous Services, D.3.6
- GRANT statement, B.1
- Group functions, B.2.2.3
H
- Heterogeneous Services
- Hexadecimal notation, 2.7.4.1
- HS_CALL_NAME initialization parameter, D.3.1
- HS_DB_NAME initialization parameter, D.3.4
- HS_DESCRIBE_CACHE_HWM initialization parameter, D.3.5
- HS_FDS_CONNECT_INFO, D.3.14
- HS_FDS_FETCH_ROWS parameter, D.3.21
- HS_FDS_PROC_IS_FUNC initialization parameter, D.3.15
- HS_FDS_RECOVERY_PWD initialization parameter, D.3.30
- HS_FDS_RESULTSET_SUPPORT initialization parameter, D.3.18
- HS_FDS_TRACE_LEVEL initialization parameter, D.3.19
-
- enabling agent tracing, D.1
- HS_FDS_TRANSACTION_LOG initialization parameter, D.3.20
- HS_IDLE_TIMEOUT initialization parameter, D.3.23
- HS_KEEP_REMOTE_COLUMN_SIZE initialization parameter, D.3.25
- HS_LANGUAGE initialization parameter, D.3.6
- HS_LONG_PIECE_TRANSFER_SIZE initialization parameter, D.3.7
- HS_NLS_LENGTH_SEMANTICS initialization parameter, D.3.24
- HS_OPEN_CURSORS initialization parameter, D.3.8
- HS_RPC_FETCH_REBLOCKING initialization parameter, D.3.9
- HS_RPC_FETCH_SIZE initialization parameter, D.3.10
- HS_TIME_ZONE initialization parameter, D.3.11
I
- IFILE initialization parameter, D.3.13
- IMAGE data type, A.1
- Initialization parameter file
-
- customizing, D
- INSERT statement, 2.8.7.4, 3.9.3, B.1.2, B.2.1
- INTEGER data type, A.1
K
- Known restrictions, 2.8
L
M
- MONEY data type, A.1
N
O
P
- parameters
-
- gateway initialization file
-
- HS_FDS_FETCH_ROWS, D.3.21
- Passing commands to database, 2.8.5
- Pass-Through Feature, 3.11
- Pass-through feature, 2.8.5
- PL/SQL, 2.9.5, 2.9.6
R
- RAW data type, A.1
- REAL data type, A.1
- remote functions
-
- referenced in SQL statements, D.3.1
- ROLLBACK
-
- restrictions, 2.8.3
- ROWID, 2.8.7.1, 2.8.7.3
S
- savepoint support, 2.8.2
- SELECT statement, 3.11.2, B.1.3, C.1.2
- SMALL DATETIME data type, A.1
- SMALLINT data type, A.1
- Stored procedures, 2.8.4, 2.9.7
-
- running in chained mode, 2.7.1
- Stored procedures in SQL Server, 2.2
- String functions, B.2.2.4, B.2.2.4
- SUM function, 3.7
T
- TEXT data type, A.1
- TINYINT data type, A.1
- Transaction modes, 2.7.1
- transactional capability, 2.8.2
- transactional integrity, 2.8.1
- TRUNCATE statement, B.1
- Two-phase commit, 2.8.2
U
V
W
- WHERE CURRENT OF clause, 2.8.7.1
A Data Type Conversion
This appendix contains the following section:
A.1 Data Type Conversion
The gateway converts Sybase data types to Oracle data types as follows:
Table A-1 Data Type Conversions
| Sybase | Oracle | Comment |
|---|---|---|
|
|
| |
|
- | ||
|
- | ||
|
|
- | |
|
|
| |
|
- | ||
|
|
- | |
|
|
- | |
|
- | ||
|
|
| |
|
|
- | |
|
|
- | |
|
|
- | |
|
|
- | |
|
|
| |
|
|
- | |
|
|
| |
|
- | ||
|
|
| |
|
|
| |
|
|
- | |
|
|
|
- |
|
|
| |
|
|
| |
|
|
| |
|
|
|
if Oracle DB Character Set = Unicode. Otherwise, it is not supported |
|
|
|
- |
|
|
- | |
|
- |
Oracle Legal Notices
Copyright Notice
Copyright © 1994-2012, Oracle and/or its affiliates. All rights reserved.
Trademark Notice
Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.
Intel and Intel Xeon are trademarks or registered trademarks of Intel Corporation. All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. AMD, Opteron, the AMD logo, and the AMD Opteron logo are trademarks or registered trademarks of Advanced Micro Devices. UNIX is a registered trademark of The Open Group.
License Restrictions Warranty/Consequential Damages Disclaimer
This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.
Warranty Disclaimer
The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.
Restricted Rights Notice
If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:
U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle America, Inc., 500 Oracle Parkway, Redwood City, CA 94065.
Hazardous Applications Notice
This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.
Third-Party Content, Products, and Services Disclaimer
This software or hardware and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.
Alpha and Beta Draft Documentation Notice
If this document is in prerelease status:
This documentation is in prerelease status and is intended for demonstration and preliminary use only. It may not be specific to the hardware on which you are using the software. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to this documentation and will not be responsible for any loss, costs, or damages incurred due to the use of this documentation.
Contents
List of Tables
Title and Copyright Information
Preface
1 Introduction
2 Sybase Gateway Features and Restrictions
- 2.1 Using the Pass-Through Feature
- 2.2 Executing Stored Procedures and Functions
- 2.3 CHAR Semantics
- 2.4 Multi-byte Character Sets Ratio Suppression
- 2.5 IPv6 Support
- 2.6 Gateway Session IDLE Timeout
- 2.7 Database Compatibility Issues for Sybase
- 2.8 Known Restrictions
- 2.8.1 Transactional Integrity
- 2.8.2 Transaction Capability
- 2.8.3 COMMIT or ROLLBACK in PL/SQL Cursor Loops Closes Open Cursors
- 2.8.4 Stored Procedures
- 2.8.5 Pass-Through Feature
- 2.8.6 Sybase NCHAR and NVARCHAR Data Types
- 2.8.7 SQL Syntax
- 2.8.8 SQL*Plus COPY Command with Lowercase Table Names
- 2.8.9 Database Links
- 2.8.10 CALLBACK links
- 2.9 Known Problems
3 Case Studies
- 3.1 Case Descriptions
- 3.2 Distribution Media Contents
- 3.3 Demonstration Files
- 3.4 Demonstration Requirements
- 3.5 Creating Demonstration Tables
- 3.6 Case 1: Simple Queries
- 3.7 Case 2: A More Complex Query
- 3.8 Case 3: Joining Sybase Tables
- 3.9 Case 4: Write Capabilities
- 3.10 Case 5: Data Dictionary Query
- 3.11 Case 6: The Pass-Through Feature
- 3.12 Case 7: Executing Stored Procedures
A Data Type Conversion
B Supported SQL Syntax and Functions
C Data Dictionary
D Initialization Parameters
- D.1 Initialization Parameter File Syntax
- D.2 Oracle Database Gateway for Sybase Initialization Parameters
- D.3 Initialization Parameter Description
- D.3.1 HS_CALL_NAME
- D.3.2 HS_DB_DOMAIN
- D.3.3 HS_DB_INTERNAL_NAME
- D.3.4 HS_DB_NAME
- D.3.5 HS_DESCRIBE_CACHE_HWM
- D.3.6 HS_LANGUAGE
- D.3.7 HS_LONG_PIECE_TRANSFER_SIZE
- D.3.8 HS_OPEN_CURSORS
- D.3.9 HS_RPC_FETCH_REBLOCKING
- D.3.10 HS_RPC_FETCH_SIZE
- D.3.11 HS_TIME_ZONE
- D.3.12 HS_TRANSACTION_MODEL
- D.3.13 IFILE
- D.3.14 HS_FDS_CONNECT_INFO
- D.3.15 HS_FDS_PROC_IS_FUNC
- D.3.16 HS_FDS_RECOVERY_ACCOUNT
- D.3.17 HS_FDS_RECOVERY_PWD
- D.3.18 HS_FDS_RESULTSET_SUPPORT
- D.3.19 HS_FDS_TRACE_LEVEL
- D.3.20 HS_FDS_TRANSACTION_LOG
- D.3.21 HS_FDS_FETCH_ROWS
- D.3.22 HS_FDS_QUOTE_IDENTIFIER
- D.3.23 HS_IDLE_TIMEOUT
- D.3.24 HS_NLS_LENGTH_SEMANTICS
- D.3.25 HS_KEEP_REMOTE_COLUMN_SIZE
- D.3.26 HS_FDS_REMOTE_DB_CHARSET
- D.3.27 HS_FDS_SUPPORT_STATISTICS
- D.3.28 HS_FDS_RSET_RETURN_ROWCOUNT
- D.3.29 HS_FDS_SQLLEN_INTERPRETATION
- D.3.30 HS_FDS_REPORT_REAL_AS_DOUBLE
Index
C Data Dictionary
The Oracle Database Gateway for Sybase translates a query that refers to an Oracle database data dictionary table into a query that retrieves the data from Sybase system tables. You perform queries on data dictionary tables over the database link in the same way you query data dictionary tables in the Oracle database. The gateway data dictionary is similar to the Oracle database data dictionary in appearance and use.
This appendix contains the following sections:
C.1 Data Dictionary Support
The following paragraphs describe the Oracle Database Gateway for Sybase data dictionary support.
C.1.1 Sybase System Tables
Sybase data dictionary information is stored in the Sybase database as Sybase system tables. All Sybase system tables have names prefixed with "sys". The Sybase system tables define the structure of a database. When you change data definitions, Sybase reads and modifies the Sybase system tables to add information about the user tables.
C.1.2 Accessing the Gateway Data Dictionary
Accessing a gateway data dictionary table or view is identical to accessing a data dictionary in an Oracle database. You issue a SQL SELECT statement specifying a database link. The Oracle database data dictionary view and column names are used to access the gateway data dictionary in an Oracle database. Synonyms of supported views are also acceptable. For example, the following statement queries the data dictionary table ALL_CATALOG to retrieve all table names in the Sybase database:
SQL> SELECT * FROM "ALL_CATALOG"@SYBS;
When a data dictionary access query is issued, the gateway:
-
Maps the requested table, view, or synonym to one or more Sybase system table names. The gateway translates all data dictionary column names to their corresponding Sybase column names within the query. If the mapping involves one Sybase system table, the gateway translates the requested table name to its corresponding Sybase system table name within the query. If the mapping involves multiple Sybase system tables, the gateway constructs a join in the query using the translated Sybase system table names.
-
Sends the translated query to Sybase.
-
Might convert the retrieved Sybase data to give it the appearance of the Oracle database data dictionary table.
-
Passes the data dictionary information from the translated Sybase system table to the Oracle database.
Note:
The values returned when querying the gateway data dictionary might not be the same as the ones returned by the Oracle SQL*PlusDESCRIBEcommand.
C.1.3 Direct Queries to Sybase Tables
Queries issued directly to individual Sybase system tables are allowed but they return different results because the Sybase system table column names differ from those of the data dictionary view. Also, certain columns in an Sybase system table cannot be used in data dictionary processing.
C.1.4 Supported Views and Tables
The gateway supports the following views and tables:
| Supported Views and Tables | Supported Views and Tables |
|---|---|
ALL_CATALOG | ALL_COL_COMMENTS |
ALL_CONS_COLUMNS | ALL_CONSTRAINTS |
ALL_IND_COLUMNS | ALL_INDEXES |
ALL_OBJECTS | ALL_TAB_COLUMNS |
ALL_TAB_COMMENTS | ALL_TABLES |
ALL_USERS | ALL_VIEWS |
DBA_CATALOG | DBA_COL_COMMENTS |
DBA_OBJECTS | DBA_TABLES |
DBA_TAB_COLUMNS | DBA_TAB_COMMENTS |
DICT_COLUMNS | DICTIONARY |
DUAL | TABLE_PRIVILEGES |
USER_CATALOG | USER_COL_COMMENTS |
USER_CONS_COLUMNS | USER_CONSTRAINTS |
USER_IND_COLUMNS | USER_INDEXES |
USER_OBJECTS | USER_TAB_COLUMNS |
USER_TAB_COMMENTS | USER_TABLES |
USER_USERS | USER_VIEWS |
No other Oracle database data dictionary tables or views are supported. If you use a view not on the list, you receive the Oracle database error code for no more rows available.
Queries through the gateway of any data dictionary table or view beginning with ALL_ can returns rows from the Sybase database even when access privileges for those Sybase objects have not been granted. When querying an Oracle database with the Oracle data dictionary, rows are returned only for those objects you are permitted to access.
C.2 Data Dictionary Mapping
The tables in this section list Oracle data dictionary view names and the equivalent Sybase system tables used. A plus sign (+) indicates that a join operation is involved.
Table C-1 Oracle Data Dictionary View Names and Sybase Equivalents
| View Name | Sybase System Table Name |
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
(Defined in the Gateway) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
C.2.1 Default Column Values
There is a minor difference between the gateway data dictionary and a typical Oracle database data dictionary. The Oracle database columns that are missing in an Sybase system table are filled with zeros, spaces, null values, not-applicable values (N.A.), or default values, depending on the column type.
C.3 Gateway Data Dictionary Descriptions
The gateway data dictionary tables and views provide the following information:
-
Name, data type, and width of each column
-
The contents of columns with fixed values
They are described here with information retrieved by an Oracle SQL*Plus DESCRIBE command. The values in the Null? column might differ from the Oracle database data dictionary tables and views. Any default value is shown to the right of an item, but this is not information returned by DESCRIBE.
Table C-2 ALL_CATALOG
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
Table C-3 ALL_COL_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" " |
Table C-4 ALL_CONS_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
Table C-5 ALL_CONSTRAINTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- |
Table C-6 ALL_IND_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
Table C-7 ALL_INDEXES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-8 ALL_OBJECTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
0 |
|
|
|
" |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
Table C-9 ALL_TAB_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-10 ALL_TAB_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
|
Table C-11 ALL_TABLES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
Table C-12 ALL_USERS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
Table C-13 ALL_VIEWS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
|
|
|
|
" " |
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
Table C-14 DBA_CATALOG
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
Table C-15 DBA_COL_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" " |
Table C-16 DBA_OBJECTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
|
|
|
|
" |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-17 DBA_TAB_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-18 DBA_TAB_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
|
Table C-19 DBA_TABLES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
|
|
|
|
|
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
|
|
|
" " |
Table C-20 DICT_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" " |
Table C-23 TABLE_PRIVILEGES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
" |
|
|
|
" |
|
|
|
" |
|
|
|
" |
|
|
|
" |
|
|
|
" |
|
|
|
- |
Table C-24 USER_CATALOG
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
" |
Table C-25 USER_COL_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
|
Table C-26 USER_CONS_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
Table C-27 USER_CONSTRAINTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- |
Table C-28 USER_IND_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
Table C-29 USER_INDEXES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-30 USER_OBJECTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
|
|
|
|
- |
|
|
|
0 |
|
|
|
" |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
Table C-31 USER_TAB_COLUMNS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
- |
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-32 USER_TAB_COMMENTS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
" |
|
|
|
|
Table C-33 USER_TABLES
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Table C-34 USER_USERS
| Name | Type | Value |
|---|---|---|
|
|
|
- |
|
|
|
- |
|
|
|
" |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
3 Case Studies
The following case studies for Sybase demonstrate some of the features of the Oracle Database Gateway. You can verify that the gateway is installed and operating correctly by using the demonstration files included on the distribution media.
The demonstration files are automatically copied to disk when the gateway is installed.
This chapter contains the following sections:
3.1 Case Descriptions
The cases illustrate:
-
A simple query (Case 1)
-
A more complex query (Case 2)
-
Joining Sybase tables (Case 3)
-
Write capabilities (Case 4)
-
A data dictionary query (Case 5)
-
The pass-through feature (Case 6)
-
Executing stored procedures (Case 7)
3.2 Distribution Media Contents
The distribution media contains the following:
-
Demonstration files
-
One SQL script file that creates the demonstration tables and stored procedures in the Sybase database
-
One SQL script file that drops the demonstration tables and stored procedures from the Sybase database
3.3 Demonstration Files
After a successful gateway installation, use the demonstration files stored in the directory $ORACLE_HOME/dg4sybs/demo, where $ORACLE_HOME is the directory under which the gateway is installed. The directory contains the following demonstration files:
3.4 Demonstration Requirements
The case studies assume these requirements have been met:
-
The gateway demonstration tables and stored procedures are installed in the Sybase database
-
The Oracle database has an account named
SCOTTwith a password ofTIGER -
The Oracle database has a database link called
GTWLINK(set up as public or private to the userSCOTT) that connects the gateway to a Sybase database asSCOTTwith passwordTIGER2.For example, you can create the database link as follows:
SQL> CREATE DATABASE LINK GTWLINK CONNECT TO SCOTT 2 IDENTIFIED BY TIGER2 USING 'GTWSID';
-
Oracle Net Services is configured correctly and running
-
The Sybase environment variable,
SYBASE, is set correctly
3.5 Creating Demonstration Tables
The case studies are based on the GTW_EMP, GTW_DEPT, and GTW_SALGRADE tables and the stored procedures InsertDept and GetDept. If the demonstration tables and stored procedures have not been created in the Sybase database, use the bldsybs.sql script to create them. Enter the following:
$ isql -USCOTT -PTIGER2 -ibldsybs.sql
The script creates the demonstration tables and stored procedures in the Sybase database accordingly:
CREATE TABLE GTW_EMP ( EMPNO SMALLINT NOT NULL ENAME VARCHAR(10), JOB VARCHAR(9), MGR SMALLINT, HIREDATE DATETIME, SAL NUMERIC(7,2), COMM NUMERIC(7,2), DEPTNO SMALLINT) go CREATE TABLE GTW_DEPT ( DEPTNO SMALLINT NOT NULL, DNAME VARCHAR(14), LOC VARCHAR(13)) go CREATE TABLE GTW_SALGRADE ( GRADE MONEY, LOSAL NUMERIC(9,4), HISAL NUMERIC(9,4)) go SET CHAINED ON go DROP PROCEDURE InsertDept go CREATE PROCEDURE InsertDept (@dno INTEGER, @dname VARCHAR(14), @loc VARCHAR(13)) AS INSERT INTO GTW_DEPT VALUES (@dno, @dname, @loc) go DROP PROCEDURE GetDept go CREATE PROCEDURE GetDept (@dno INTEGER, @dname VARCHAR(14) OUTPUT) AS SELECT @dname=DNAME FROM GTW_DEPT WHERE DEPTNO=@dno go
3.5.1 Demonstration Table Definitions
The table definitions are listed in the following table using information retrieved by the SQL*PLUS DESCRIBE command:
GTW_EMP
Name Null? Type ------------------------------- -------- ---- EMPNO NOT NULL NUMBER(5) ENAME VARCHAR2(10) JOB VARCHAR2(9) MGR NUMBER(5) HIREDATE DATE SAL NUMBER(7,2) COMM NUMBER(7,2) DEPTNO NUMBER(5)
GTW_DEPT
Name Null? Type ------------------------------- -------- ---- DEPTNO NOT NULL NUMBER(5) DNAME VARCHAR2(14) LOC VARCHAR2(13)
GTW_SALGRADE
Name Null? Type ------------------------------- -------- ---- GRADE NUMBER(19,4) LOSAL NUMBER(9,4) HISAL NUMBER(9,4)
3.5.2 Demonstration Table Contents
The contents of the Sybase tables are:
GTW_EMP
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO ----- ----- --- --- -------- --- ---- ------ 7369 SMITH CLERK 7902 17-DEC-80 800 20 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 300 30 7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30 7566 JONES MANAGER 7839 02-APR-81 2975 20 7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30 7698 BLAKE MANAGER 7839 01-MAY-81 2850 30 7782 CLARK MANAGER 7839 09-JUN-81 2450 10 7788 SCOTT ANALYST 7566 09-DEC-82 3000 20 7839 KING PRESIDENT 17-NOV-81 5000 10 7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30 7876 ADAMS CLERK 7788 12-JAN-83 1100 20 7900 JAMES CLERK 7698 03-DEC-81 950 30 7902 FORD ANALYST 7566 03-DEC-81 3000 20 7934 MILLER CLERK 7782 23-JAN-82 1300 10
GTW_DEPT
DEPTNO DNAME LOC ----- -------------- -------- 10 ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON
GTW_SALGRADE
GRADE LOSAL HISAL
------ ------ -----
1 700 1200
2 1201 1400
3 1401 2000
4 2001 3000
5 3001 9999
3.6 Case 1: Simple Queries
Case 1 demonstrates the following:
-
A simple query
-
A simple query retrieving full date information
The first query retrieves all the data from GTW_DEPT and confirms that the gateway is working correctly. The second query retrieves all the data from GTW_EMP including the time portion of the hire date because the default date format was set to DD-MON-YY HH24:MM:SS for the session by an ALTER SESSION command.
3.7 Case 2: A More Complex Query
Case 2 demonstrates the following:
-
The functions
SUM(expression)andNVL(expr1, expr2)in theSELECTlist -
The
GROUP BYandHAVINGclauses
This query retrieves the departments from GTW_EMP whose total monthly expenses are higher than $10,000.
3.8 Case 3: Joining Sybase Tables
Case 3 demonstrates the following:
-
Joins between Sybase tables
-
Subselects
The query retrieves information from three Sybase tables and relates the employees to their department name and salary grade, but only for those employees earning more than the average salary.
3.9 Case 4: Write Capabilities
Case 4 is split into three cases and demonstrates the following:
3.9.1 DELETE Statement
Case 4a demonstrates bind values and subselect. All employees in department 20 and one employee, WARD, in department 30 are deleted.
3.9.2 UPDATE Statement
Case 4b provides an example of a simple UPDATE statement. In this example, employees are given a $100 a month salary increase.
3.10 Case 5: Data Dictionary Query
Case 5 demonstrates data dictionary mapping. It retrieves all the tables and views that exist in the Sybase database that begin with "GTW".
3.11 Case 6: The Pass-Through Feature
Case 6 demonstrates the gateway pass-through feature that allows an application to send commands or statements to Sybase.
This case demonstrates:
-
A pass-through
UPDATEstatement using bind variables -
A pass-through
SELECTstatement
3.11.1 UPDATE Statement
Case 6a provides an example of a pass-through UPDATE statement with bind variables. In this example, the salary for EMPNO 7934 is set to 4000.
2 Sybase Gateway Features and Restrictions
After the gateway is installed and configured, you can use the gateway to access Sybase data, pass Sybase commands from applications to the Sybase database, perform distributed queries, and copy data.
This chapter contains the following sections:
2.1 Using the Pass-Through Feature
The gateway can pass Sybase commands or statements from the application to the Sybase database using the DBMS_HS_PASSTHROUGH package.
Use the DBMS_HS_PASSTHROUGH package in a PL/SQL block to specify the statement to be passed to the Sybase database, as follows:
DECLARE
num_rows INTEGER;
BEGIN
num_rows := DBMS_HS_PASSTHROUGH.EXECUTE_IMMEDIATE@SYBS('command');
END;
/
Where command cannot be one of the following:
-
BEGIN TRANSACTION -
COMMIT -
ROLLBACK -
SAVE -
SHUTDOWN -
Sybase tool commands
The DBMS_HS_PASSTHROUGH package supports passing bind values and executing SELECT statements.
|
Note: TRUNCATE cannot be used in a pass-through statement. |
|
See Also: Oracle Database PL/SQL Packages and Types Reference and Chapter 3, Features of Oracle Database Gateways, of Oracle Database Heterogeneous Connectivity User's Guide for more information about theDBMS_HS_PASSTHROUGH package. |
2.2 Executing Stored Procedures and Functions
Using the procedural feature, the gateway can execute stored procedures that are defined in the Sybase database. It is not necessary to relink the gateway or define the procedure to the gateway, but the procedure's access privileges must permit access by the gateway.
|
See Also: Oracle Database Heterogeneous Connectivity User's Guide for more information about executing stored procedures. |
Standard PL/SQL statements are used to execute a stored procedure.
The gateway supports stored procedures in three mutually exclusive modes:
-
Normal mode: Have access to
IN/OUTarguments only -
Return value mode: Have a return value for all stored procedures
-
Resultset mode: Out values are available as last result set
2.2.1 Return Values and Stored Procedures
By default, all stored procedures and functions do not return a return value to the user. To enable return values, set the HS_FDS_PROC_IS_FUNC parameter in the initialization parameter file.
|
See Also: Appendix D, "Initialization Parameters" for information about both editing the initialization parameter file and theHS_FDS_PROC_IS_FUNC parameter. |
|
Note: If you set theHS_FDS_PROC_IS_FUNC gateway initialization parameter, you must change the syntax of the procedure execute statement for all existing stored procedures. |
In the following example, the employee name JOHN SMYTHE is passed to the Sybase stored procedure REVISE_SALARY. The stored procedure retrieves the salary value from the Sybase database to calculate a new yearly salary for JOHN SMYTHE. The revised salary returned in RESULT is used to update EMP in a table of an Oracle database:
DECLARE INPUT VARCHAR2(15); RESULT NUMBER(8,2); BEGIN INPUT := 'JOHN SMYTHE'; RESULT := REVISE_SALARY@SYBS(INPUT); UPDATE EMP SET SAL = RESULT WHERE ENAME =: INPUT; END; /
The procedural feature automatically converts non-Oracle data types to and from PL/SQL data types.
2.2.2 Result Sets and Stored Procedures
The Oracle Database Gateway for Sybase provides support for stored procedures which return result sets.
By default, all stored procedures and functions do not return a result set to the user. To enable result sets, set the HS_FDS_RESULTSET_SUPPORT parameter in the initialization parameter file.
|
See Also: Appendix D, "Initialization Parameters" for information about both editing the initialization parameter file and theHS_FDS_RESULTSET_SUPPORT parameter. For further information about Oracle support for result sets in non-Oracle databases see Oracle Database Heterogeneous Connectivity User's Guide. |
|
Note: If you set theHS_FDS_RESULTSET_SUPPORT gateway initialization parameter, you must change the syntax of the procedure execute statement for all existing stored procedures or errors will occur. |
When accessing stored procedures with result sets through the Oracle Database Gateway for Sybase, you will be in the sequential mode of Heterogeneous Services.
The Oracle Database Gateway for Sybase returns the following information to Heterogeneous Services during procedure description:
-
All the input arguments of the remote stored procedure
-
None of the output arguments
-
One out argument of type ref cursor (corresponding to the first result set returned by the stored procedure)
Client programs have to use the virtual package function dbms_hs_result_set.get_next_result_set to get the ref cursor for subsequent result sets. The last result set returned is the out argument from the procedure.
The limitations of accessing result sets are the following:
-
Result sets returned by a remote stored procedure have to be retrieved in the order in which they were placed on the wire
-
On execution of a stored procedure, all result sets returned by a previously executed stored procedure will be closed (regardless of whether the data has been completely
In the following example, the Sybase stored procedure is executed to fetch the contents of the emp and dept tables from Sybase:
create procedure REFCURPROC (@arg1 varchar(255), @arg2 varchar(255) output) as select @arg2 = @arg1 select * from EMP select * from DEPT go
This stored procedure assigns the input parameter arg1 to the output parameter arg2, opens the query SELECT * FROM EMP in ref cursor rc1, and opens the query SELECT * FROM DEPT in ref cursor rc2.
|
Note: Chained mode must be set before creating the stored procedure. Issue the following command in Sybase:set chained on |
2.2.2.1 OCI Program Fetching from Result Sets in Sequential Mode
The following example shows OCI program fetching from result sets in sequential mode:
OCIEnv *ENVH;
OCISvcCtx *SVCH;
OCIStmt *STMH;
OCIError *ERRH;
OCIBind *BNDH[3];
OraText arg1[20];
OraText arg2[255];
OCIResult *rset;
OCIStmt *rstmt;
ub2 rcode[3];
ub2 rlens[3];
sb2 inds[3];
OraText *stmt = (OraText *) "begin refcurproc@SYBS(:1,:2,:3); end;";
OraText *n_rs_stm = (OraText *)
"begin :ret := DBMS_HS_RESULT_SET.GET_NEXT_RESULT_SET@SYBS; end;";
/* Prepare procedure call statement */
/* Handle Initialization code skipped */
OCIStmtPrepare(STMH, ERRH, stmt, strlen(stmt), OCI_NTV_SYNTAX, OCI_DEFAULT);
/* Bind procedure arguments */
inds[0] = 0;
strcpy((char *) arg1, "Hello World");
rlens[0] = strlen(arg1);
OCIBindByPos(STMH, &BNDH[0], ERRH, 1, (dvoid *) arg1, 20, SQLT_CHR,
(dvoid *) &(inds[0]), &(rlens[0]), &(rcode[0]), 0, (ub4 *) 0,
OCI_DEFAULT);
inds[1] = -1;
OCIBindByPos(STMH, &BNDH[1], ERRH, 1, (dvoid *) arg2, 20, SQLT_CHR,
(dvoid *) &(inds[1]), &(rlens[1]), &(rcode[1]), 0, (ub4 *) 0,
OCI_DEFAULT);
inds[2] = 0;
rlens[2] = 0;
OCIDescriptorAlloc(ENVH, (dvoid **) &rset, OCI_DTYPE_RSET, 0, (dvoid **) 0);
OCIBindByPos(STMH, &BNDH[2], ERRH, 2, (dvoid *) rset, 0, SQLT_RSET,
(dvoid *) &(inds[2]), &(rlens[2]), &(rcode[2]),
0, (ub4 *) 0, OCI_DEFAULT);
/* Execute procedure */
OCIStmtExecute(SVCH, STMH, ERRH, 1, 0, (CONST OCISnapshot *) 0,
(OCISnapshot *) 0, OCI_DEFAULT);
/* Convert result set to statement handle */
OCIResultSetToStmt(rset, ERRH);
rstmt = (OCIStmt *) rset;
/* After this the user can fetch from rstmt */
/* Issue get_next_result_set call to get handle to next_result set */
/* Prepare Get next result set procedure call */
OCIStmtPrepare(STMH, ERRH, n_rs_stm, strlen(n_rs_stm), OCI_NTV_SYNTAX,
OCI_DEFAULT);
/* Bind return value */
OCIBindByPos(STMH, &BNDH[1], ERRH, 1, (dvoid *) rset, 0, SQLT_RSET,
(dvoid *) &(inds[1]), &(rlens[1]), &(rcode[1]),
0, (ub4 *) 0, OCI_DEFAULT);
/* Execute statement to get next result set*/
OCIStmtExecute(SVCH, STMH, ERRH, 1, 0, (CONST OCISnapshot *) 0,
(OCISnapshot *) 0, OCI_DEFAULT);
/* Convert next result set to statement handle */
OCIResultSetToStmt(rset, ERRH);
rstmt = (OCIStmt *) rset;
/* Now rstmt will point to the second result set returned by the
remote stored procedure */
/* Repeat execution of get_next_result_set to get the output arguments */
2.2.2.2 PL/SQL Program Fetching from Result Sets in Sequential Mode
Assume that the table loc_emp is a local table exactly like the Sybase emp table. The same assumption applies for loc_dept. outargs is a table with columns corresponding to the out arguments of the Sybase stored procedure.
create or replace package rcpackage is type RCTYPE is ref cursor; end rcpackage; /
declare
rc1 rcpackage.rctype;
rec1 loc_emp%rowtype;
rc2 rcpackage.rctype;
rec2 loc_dept%rowtype;
rc3 rcpackage.rctype;
rec3 outargs%rowtype;
out_arg varchar2(255);
begin
-- Execute procedure
out_arg := null; refcurproc@SYBS('Hello World', out_arg, rc1);
-- Fetch 20 rows from the remote emp table and insert them into loc_emp
for i in 1 .. 20 loop
fetch rc1 into rec1;
insert into loc_emp (rec1.empno, rec1.ename, rec1.job,
rec1.mgr, rec1.hiredate, rec1.sal, rec1.comm, rec1.deptno);
end loop;
-- Close ref cursor
close rc1;
-- Get the next result set returned by the stored procedure
rc2 := dbms_hs_result_set.get_next_result_set@SYBS;
-- Fetch 5 rows from the remote dept table and insert them into loc_dept
for i in 1 .. 5 loop
fetch rc2 into rec2;
insert into loc_dept values (rec2.deptno, rec2.dname, rec2.loc);
end loop;
--Close ref cursor
close rc2;
-- Get the output arguments from the remote stored procedure
-- Since we are in sequential mode, they will be returned in the
-- form of a result set
rc3 := dbms_hs_result_set.get_next_result_set@SYBS;
-- Fetch them and insert them into the outarguments table
fetch rc3 into rec3;
insert into outargs (rec3.outarg, rec3.retval);
-- Close ref cursor
close rc3;
end;
/
2.3 CHAR Semantics
This feature allows the gateway to optionally run in CHAR Semantics mode. Rather than always describing Sybase CHAR columns as CHAR(n BYTE), this feature describes them as CHAR(n CHAR) and VARCHAR(n CHAR). The concept is similar to Oracle database CHAR Semantics. You need to specify HS_NLS_LENGTH_SEMANTICS=CHAR gateway parameter to activate this option. Refer to Appendix D for more detail.
2.4 Multi-byte Character Sets Ratio Suppression
This feature optionally suppresses the ratio expansion from Sybase database to Oracle database involving multi-byte character set. By default, Oracle gateways assume the worst ratio to prevent data being truncated or insufficient buffer size situation. However, if you have specific knowledge of your Sybase database and do not want the expansion to occur, you can specify HS_KEEP_REMOTE_COLUMN_SIZE parameter to suppress the expansion. Refer to Appendix D for more detail.
2.5 IPv6 Support
Besides full IPv6 support between Oracle databases and the gateway, IPv6 is also supported between this gateway and Sybase database. Refer to the HS_FDS_CONNECT_INFO parameter in Appendix D for more detail.
2.6 Gateway Session IDLE Timeout
You can optionally choose to terminate long idle gateway sessions automatically with the gateway parameter HS_IDLE_TIMEOUT. Specifically, when a gateway session is idle for more than the specified time limit, the gateway session is terminated with any pending update rolled back.
2.7 Database Compatibility Issues for Sybase
Sybase and Oracle databases function differently in some areas, causing compatibility problems. The following compatibility issues are described in this section:
2.7.1 Chained Mode
The gateway supports the ANSI-standard chained mode. Sybase stored procedures must be written for this mode. Running in chained mode allows the gateway to extend the Oracle two-phase commit protection to transactions updating Oracle and Sybase databases.
2.7.2 Column Definitions
By default, a Sybase table column cannot contain null values unless NULL is specified in the column definition. In compliance with the ANSI standard, the Sybase database option "allow nulls by default" can be set to true to change the default column definition to NULL.
For an Oracle table, null values are allowed in a column unless NOT NULL is specified in the column definition.
2.7.3 Naming Rules
Naming rule issues include the following:
2.7.3.1 Rules for Naming Objects
Oracle and Sybase use different database object naming rules. For example, the maximum number of characters allowed for each object name can be different. Also, the use of single and double quotation marks, case sensitivity, and the use of alphanumeric characters can all be different.
2.7.3.2 Case Sensitivity
The Oracle database defaults to uppercase unless you surround identifiers with double quote characters. For example, to refer to the Sybase table called emp, enter the name with double quote characters, as follows:
SQL> SELECT * FROM "emp"@SYBS;
However, to refer to the Sybase table called emp owned by SCOTT from an Oracle application, enter the following:
SQL> SELECT * FROM "Scott"."emp"@SYBS;
If the Sybase table called emp is owned by SCOTT, a table owner name in uppercase letters, you can enter the owner name without double quote characters, as follows:
SQL> SELECT * FROM SCOTT."emp"@SYBS;
Or
SQL> SELECT * FROM scott."emp"@SYBS;
Oracle recommends that you surround all Sybase object names with double quote characters and use the exact letter case for the object names as they appear in the Sybase data dictionary. This convention is not required when referring to the supported Oracle data dictionary tables or views listed in Appendix C, "Data Dictionary".
If existing applications cannot be changed according to these conventions, create views in Oracle to associate Sybase names to the correct letter case. For example, to refer to the Sybase table emp from an existing Oracle application by using only uppercase names, define the following view:
SQL> CREATE VIEW EMP (EMPNO, ENAME, SAL, HIREDATE)
AS SELECT "empno", "ename", "sal", "hiredate"
FROM "emp"@SYBS;
With this view, the application can issue statements such as the following:
SQL> SELECT EMPNO, ENAME FROM EMP;
Using views is a workaround solution that duplicates data dictionary information originating in the Sybase data dictionary. You must be prepared to update the Oracle view definitions whenever the data definitions for the corresponding tables are changed in the Sybase database.
2.7.4 Data Types
Data type issues include the following:
2.7.4.1 Binary Literal Notation
Oracle SQL uses hexadecimal digits surrounded by single quotes to express literal values being compared or inserted into columns defined as data type RAW.
This notation is not converted to syntax compatible with the Sybase VARBINARY and BINARY data types (a 0x followed by hexadecimal digits, surrounded by single quotes).
For example, the following statement is not supported:
SQL> INSERT INTO BINARY_TAB@SYBS VALUES ('0xff')
Where BINARY_TAB contains a column of data type VARBINARY or BINARY. Use bind variables when inserting into or updating VARBINARY and BINARY data types.
2.7.4.2 Data Type Conversion
Sybase does not support implicit date conversions. Such conversions must be explicit.
For example, the gateway issues an error for the following SELECT statement:
SELECT DATE_COL FROM TEST@SYBS WHERE DATE_COL = "1-JAN-2001";
To avoid problems with implicit conversions, add explicit conversions, as in the following:
SELECT DATE_COL FROM TEST@SYBS WHERE DATE_COL = TO_DATE("1-JAN-2001")
2.7.5 Queries
Query issues include the following:
2.7.5.1 Row Selection
Sybase evaluates a query condition for all selected rows before returning any of the rows. If there is an error in the evaluation process for one or more rows, no rows are returned even though the remaining rows satisfy the condition.
Oracle evaluates the query condition row-by-row and returns a row when the evaluation is successful. Rows are returned until a row fails the evaluation.
2.7.5.2 Empty Strings
Oracle processes an empty string in a SQL statement as a null value. Sybase processes an empty string as an empty string.
When comparing an empty string, the gateway passes literal empty strings to the Sybase database without any conversion. If you intended an empty string to represent a null value, Sybase does not process the statement that way; it uses the empty string.
You can avoid this problem by using NULL or IS NULL in the SQL statement instead of the empty string syntax, as in the following example:
SELECT * from "emp"@SYBS where "ename" IS NULL;
Selecting an empty string
For VARCHAR columns, the gateway returns an empty string to the Oracle database as NULL value.
For CHAR columns, the gateway returns the full size of the column with each character as empty space (' ').
2.7.5.3 Empty Bind Variables
For VARCHAR bind variables, the gateway passes empty bind variables to the Sybase database as a NULL value.
2.7.6 Locking
The locking model for a Sybase database differs significantly from the Oracle model. The gateway depends on the underlying Sybase behavior, so Oracle applications that access Sybase through the gateway can be affected by the following possible scenarios:
-
Read access might block write access
-
Write access might block read access
-
Statement-level read consistency is not guaranteed
See Also:
Sybase documentation for information about the Sybase locking model.
2.7.7 Sybase Identifiers Length Limit
By default, the gateway will always quote identifiers. However, certain Sybase releases have a limit of 30 characters for identifiers such as table or column names and quotes are considered part of the names when checking against this limit. Therefore, when quotes are used, you can only specify 28 characters. In order to support the maximum length limit in those Sybase releases, you need to specify HS_FDS_QUOTE_IDENTIFIER=FALSE in your gateway initialization parameter file. Setting this initialization parameter will cause the gateway to send identifiers without quotes. However, it has the side effect of precluding the use of identifiers that contain dots (.) or spaces, and the identifiers will follow the case sensitivity of the Sybase database being used.
2.8 Known Restrictions
If you encounter incompatibility problems not listed in this section or in "Known Problems", contact Oracle Support Services. The following section describes the known restrictions and includes suggestions for dealing with them when possible:
The following restriction also applies:
-
When negative numbers are used as the second parameter in a
SUBSTRfunction, incorrect results are returned. This is due to incompatibility between the OracleSUBSTRfunction and the equivalent in Sybase.
Note:
If you have any questions or concerns about the restrictions, contact Oracle Support Services.
2.8.1 Transactional Integrity
The gateway cannot guarantee transactional integrity in the following cases:
-
When a statement that is processed by the gateway causes an implicit commit in the target database
-
When the target database is configured to work in autocommit mode
Note:
Oracle strongly recommends the following:-
If you know that executing a particular statement causes an implicit commit in the target database, then ensure that this statement is executed in its own transaction.
-
Do not configure the target database to work in autocommit mode.
-
2.8.2 Transaction Capability
The gateway does not support savepoints. If a distributed update transaction is under way involving the gateway and a user attempts to create a savepoint, the following error occurs:
ORA-02070: database dblink does not support savepoint in this context
By default, the gateway is configured as COMMIT_CONFIRM and it is always the commit point site when the Sybase database is updated by the transaction.
2.8.3 COMMIT or ROLLBACK in PL/SQL Cursor Loops Closes Open Cursors
Any COMMIT or ROLLBACK issued in a PL/SQL cursor loop closes all open cursors, which can result in the following error:
ORA-1002: fetch out of sequence
To prevent this error, move the COMMIT or ROLLBACK statement outside the cursor loop.
2.8.4 Stored Procedures
Changes issued through stored procedures that embed commits or rollbacks cannot be controlled by the Oracle transaction manager or Oracle COMMIT or ROLLBACK commands.
When accessing stored procedures with result sets through the Oracle Database Gateway for Sybase, you must work in the sequential mode of Heterogeneous Services.
When accessing stored procedures with multiple result sets through the Oracle Database Gateway for Sybase, you must read all the result sets before continuing.
Output parameters of stored procedures must be initialized to a NULL value.
Oracle Database Gateway for Sybase does not support output parameters or stored procedures with output parameters, inside a pass through query.
2.8.5 Pass-Through Feature
DDL statements executed by Sybase using the gateway pass-through feature might fail if they are in a multi-statement transaction. Set the Sybase option "ddl in tran" to allow DDL statements in a transaction.
Oracle recommends that you place a DDL statement in its own transaction when executing such a statement with the pass-through feature. An explicit COMMIT must be issued after the DDL statement.
If the SQL statements being passed through the gateway result in an implicit commit at the Sybase database, the Oracle transaction manager is unaware of the commit and an Oracle ROLLBACK command cannot be used to roll back the transaction.
2.8.6 Sybase NCHAR and NVARCHAR Data Types
The gateway cannot select a column defined with a Sybase NCHAR or NVARCHAR data type.
2.8.7 SQL Syntax
This section lists restrictions on the following SQL syntax:
|
See Also: Appendix B, "Supported SQL Syntax and Functions" for more information about restrictions on SQL syntax. |
2.8.7.1 WHERE CURRENT OF Clause
UPDATE and DELETE statements with the WHERE CURRENT OF clause are not supported by the gateway because they rely on the Oracle ROWID implementation. To update or delete a specific row through the gateway, a condition style WHERE clause must be used.
2.8.7.4 Subqueries in INSERT Statement
Subqueries of INSERT statements cannot use multiple aliases for the same table. For example, the following statement is not supported:
SQL> INSERT INTO "emp_target"@SYBS
SELECT a."empno" FROM "emp_source"@SYBS a,
"emp_source"@SYBS b WHERE b."empno"=9999
2.8.7.5 EXPLAIN PLAN Statement
The EXPLAIN PLAN statement is not supported.
2.8.7.6 Callback Support
SQL statements that require the gateway to callback to Oracle database would not be supported.
The following categories of SQL statements will result in a callback:
-
Any DML with a sub-select, which refers to a table in Oracle database. For example:
INSERT INTO emp@non_oracle SELECT * FROM oracle_emp;
-
Any
DELETE,INSERT,UPDATEor "SELECT... FOR UPDATE..."SQL statement containing SQL functions or statements that needs to be executed at the originating Oracle database.These SQL functions include
USER,USERENV, andSYSDATE, and the SQL statements are in selects of data from the originating Oracle database. For example:DELETE FROM emp@non_oracle WHERE hiredate > SYSDATE;
SELECT ename FROM tkhoemp@non_oracle WHERE hiredate IN (SELECT hiredate FROM tkhoemp) FOR UPDATE OF empno;
-
Any SQL statement that involves a table in Oracle database, and a
LONGorLOBcolumn in a remote table. For example:SELECT a.long1, b.empno FROM scott.table@non_oracle a, emp b WHERE a.id=b.empno;
SELECT a.long1, b.dummy FROM table_non@non_oracle a, dual b;
where a.long1 is a LONG column.
2.8.8 SQL*Plus COPY Command with Lowercase Table Names
You need to use double quotes to wrap around lowercase table names.
For example:
copy from tkhouser/tkhouser@inst1 insert loc_tkhodept using select * from "tkhodept"@holink2;
2.8.9 Database Links
The gateway is not multithreaded and cannot support shared database links. Each gateway session spawns a separate gateway process and connections cannot be shared.
2.8.10 CALLBACK links
Oracle Database Gateway for Sybase does not support CALLBACK links. Trying a CALLBACK link with the gateway will return the following error message:
ORA-02025: All tables in the SQL statement must be at the remote database
2.9 Known Problems
This section describes known problems and includes suggestions for correcting them when possible. If you have any questions or concerns about the problems, contact Oracle Support Services. A current list of problems is available online. Contact your local Oracle office for information about accessing the list.
The following known problems are described in this section:
2.9.1 Encrypted Format Login
Oracle database no longer supports the initialization parameter DBLINK_ENCRYPT_LOGIN. Up to version 7.3, this parameter's default TRUE value prevented the password for the login user ID from being sent over the network (in the clear). Later versions automatically encrypt the password.
2.9.2 Date Arithmetic
The following SQL expressions do not function correctly with the gateway:
date + numbernumber + datedate - numberdate1 - date2
Statements with the preceding expressions are sent to the Sybase database without any translation. Since Sybase does not support these date arithmetic functions, the statements return an error.
2.9.3 Sybase IMAGE and TEXT Data Type
The following restrictions apply when using IMAGE and TEXT data types:
-
An unsupported SQL function cannot be used in a SQL statement that accesses a column defined as Sybase data type
IMAGEorTEXT. -
You cannot use SQL*Plus to select data from a column defined as Sybase data type
IMAGEorTEXTwhen the data is greater than 80 characters in length. Oracle recommends using Pro*C or Oracle Call Interface to access such data in a Sybase database. -
IMAGEandTEXTdata cannot be read through pass-through queries.
The gateway does not support the PL/SQL function COLUMN_VALUE_LONG of the DBMS_SQL package.
|
See Also: Appendix B, "Supported SQL Syntax and Functions" for more information about restrictions on SQL syntax. |
2.9.4 String Functions
If you concatenate numeric literals using the "||" operator when using the gateway to query a Sybase database, the result is an arithmetic addition. For example, the result of the following statement is 18:
SQL> SELECT 9 || 9 FROM DUAL@SYBS;
The result is 99 when using Oracle to query an Oracle database.
2.9.5 Schema Names and PL/SQL
If you do not prefix a Sybase database object with its schema name in a SQL statement within a PL/SQL block, the following error message occurs:
ORA-6550 PLS-201 Identifier table_name must be declared.
Change the SQL statement to include the schema name of the object.
2.9.6 Data Dictionary Views and PL/SQL
You cannot refer to data dictionary views in SQL statements that are inside a PL/SQL block.
List of Tables
- A-1 Data Type Conversions
- C-1 Oracle Data Dictionary View Names and Sybase Equivalents
- C-2 ALL_CATALOG
- C-3 ALL_COL_COMMENTS
- C-4 ALL_CONS_COLUMNS
- C-5 ALL_CONSTRAINTS
- C-6 ALL_IND_COLUMNS
- C-7 ALL_INDEXES
- C-8 ALL_OBJECTS
- C-9 ALL_TAB_COLUMNS
- C-10 ALL_TAB_COMMENTS
- C-11 ALL_TABLES
- C-12 ALL_USERS
- C-13 ALL_VIEWS
- C-14 DBA_CATALOG
- C-15 DBA_COL_COMMENTS
- C-16 DBA_OBJECTS
- C-17 DBA_TAB_COLUMNS
- C-18 DBA_TAB_COMMENTS
- C-19 DBA_TABLES
- C-20 DICT_COLUMNS
- C-21 DICTIONARY
- C-22 DUAL
- C-23 TABLE_PRIVILEGES
- C-24 USER_CATALOG
- C-25 USER_COL_COMMENTS
- C-26 USER_CONS_COLUMNS
- C-27 USER_CONSTRAINTS
- C-28 USER_IND_COLUMNS
- C-29 USER_INDEXES
- C-30 USER_OBJECTS
- C-31 USER_TAB_COLUMNS
- C-32 USER_TAB_COMMENTS
- C-33 USER_TABLES
- C-34 USER_USERS
- C-35 USER_VIEWS