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Oracle® Database Gateway for DRDA User's Guide
11g Release 1 (11.1)

B31046-01
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2 Release Information

This chapter provides information specific to the 11g release of the Oracle Database Gateway for DRDA. It includes the following sections:

2.1 Product Set

The following production components are included on the product installation media:

2.2 Changes and Enhancements

The following are the changes and enhancements unique to the 11g release of the gateway.

SNA protocol Desupported

Protocol support for SNA network communication has been discontinued. Customers should migrate existing installations to use the TCP/IP protocol.

SQL/DS and DB2 on VM targets Desupported

Support for access to SQL/DS or DB2 on VM has been discontinued.

Gateway Password Encryption Tool

The Gateway Password Encryption tool (g4drpwd) has been replaced by a generic feature which is now part of Heterogeneous Services. Refer to Chapter 15, "Security Considerations" in Oracle Database Gateway Installation and Configuration Guide for AIX 5L Based Systems (64-Bit), HP-UX PA-RISC (64-Bit), Solaris Operating System (SPARC 64-Bit), Linux x86, and Linux x86-64 or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows for details..

2.3 Product Migration

Refer to Chapter 16, "Migration From Previous Releases" in Oracle Database Gateway Installation and Configuration Guide for AIX 5L Based Systems (64-Bit), HP-UX PA-RISC (64-Bit), Solaris Operating System (SPARC 64-Bit), Linux x86, and Linux x86-64 or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows for information on migrating product configurations from previous releases for additional changes or requirements.

2.4 Known Problems

The problems that are documented in the following section are specific to the Oracle Database Gateway for DRDA, and are known to exist in this release of the product. These problems will be fixed in a future gateway release. If you have any questions or concerns about these problems, contact Oracle Support Services.

A current list of problems is available online. Contact your local Oracle office for information about accessing this online information.

2.5 Known Restrictions

The following restrictions are known to exist for the products in the 11g release. Restrictions are not scheduled to change in future releases. Refer to Chapter 4, "Developing Applications", for information or limitations when developing your applications.

Accessing DB2 Alias Objects

If you need to access DB2 alias objects on a remote DB2 system, then you must specify DRDA_DESCRIBE_TABLE=FALSE initialization parameter in the gateway initialization file.

Oracle SQL Command INSERT

When copying data from an Oracle database to a DRDA server, the Oracle SQL command INSERT is not supported. The SQL*Plus COPY command must be used. Refer to Chapter 3, "Using the Oracle Database Gateway for DRDA", for more information.

The following are the considerations and limitations:

Stored Procedure and User Defined Function Support

The gateway supports execution of stored procedures and user defined functions through the following DRDA servers:

DB2/OS390 V4.1 or later

DB2/400 V3.1 or later

DB2/UDB V7.1 or later

2.5.1 DB2 Considerations

The following considerations are exist in the 11g release:

DD Basic Tables and Views

The owner of DD basic tables and views is OTGDB2. This cannot be changed.

SUBSTR Function Post-Processed

The SUBSTR function can be used with the Oracle database in ways that are not compatible with a DRDA server database, such as DB2/OS390. Therefore, the SUBSTR function is post-processed. However, it is possible to allow the server to process it natively using the "Native Semantics" feature. Refer to Chapter 4, "Developing Applications", for details.

Support for DRDA Server Character Sets

Support for character sets used by a DRDA server is configurable through the gateways Codepage Map Facility. Refer to Appendix C, "Globalization Support for DRDA" for more information.

Data type Limitations

Refer to "DRDA Data type to Oracle Data type Conversion" for detailed information about data types

SAVEPOINT Command Is Not Supported

Oracle Database Gateway for DRDA does not support the SQL SAVEPOINT.

Null Values and Stored Procedures

Null values are not passed into, or returned from, calls to stored procedures through the gateway.

String Concatenation of Numbers

String concatenation of numbers is not allowed in DB2/400, DB2/UDB, and DB2/OS390. For example, 2||2 is not allowed.

GLOBAL_NAMES Initialization Parameter

If GLOBAL_NAMES is set to TRUE in the Oracle database INIT.ORA file, then in order to be able to connect to the gateway, you must specify the Heterogeneous Services (HS) initialization parameter, HS_DB_DOMAIN, in the Gateway Initialization Parameter file to match the value of the DB_DOMAIN parameter of the Oracle database. Refer to Chapter 14, "Configuring Oracle Database Gateway for DRDA" in Oracle Database Gateway Installation and Configuration Guide for AIX 5L Based Systems (64-Bit), HP-UX PA-RISC (64-Bit), Solaris Operating System (SPARC 64-Bit), Linux x86, and Linux x86-64 or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows , depending on your platform, for more information.

Binding the DRDA Package on DB2/UDB

The DRDA gateway package must be bound on the DRDA server before the gateway can perform any SQL operations. Because of a DB2/UDB restriction, the ORACLE2PC table must be created in the DB2/UDB database before the package can be bound. Refer to Chapter 14, "Configuring Oracle Database Gateway for DRDA" in Oracle Database Gateway Installation and Configuration Guide for AIX 5L Based Systems (64-Bit), HP-UX PA-RISC (64-Bit), Solaris Operating System (SPARC 64-Bit), Linux x86, and Linux x86-64 or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows , depending on your platform, for more information.

Date Arithmetic

In general, the following types of SQL expression forms do not work correctly with the gateway because of DRDA Serve limitations:

date + number
number + date
date - number
date1 - date2

DRDA server does not allow number addition or subtraction with date data types. The date and number addition and subtraction (date + number, number + date, date - number) forms are sent through to the DRDA server where they are rejected.

Also, DRDA server does not perform date subtraction consistently. When you subtract two dates (date1 - date2), differing interpretations of date subtraction in the DRDA server cause the results to vary by server.

Note:

Avoid date arithmetic expressions in all gateway SQL until date arithmetic problems are resolved.

Row Length Limitation

Because of a restriction of the DRDA architecture, rows with aggregate length exceeding 32KB in DRDA representation cannot be stored or retrieved.

LONG Data type in SQL*Plus

SQL*Plus cannot fetch LONG columns from the Oracle Database Gateway for DRDA.

Single Gateway Instance per DRDA Network Interface

When installing the gateway, a proper DRDA Network Interface must be chosen. Only one DRDA Network Interface may be chosen and installed per gateway instance. If the gateway product is reinstalled, and if a Network Interface different from the previous installation is chosen, then the new choice will overlay the current installation. Reconfiguration of the Gateway Initialization Parameters must occur at this point in order to ensure proper gateway operation.

Stored Procedures and Transaction Integrity

IBM DB2 has introduced a feature called Commit on Return for stored procedures. This feature allows DB2 to perform an automatic commit after a stored procedure runs successfully. This feature is enabled when the procedure is created. To ensure data integrity, this feature is not supported by the Oracle Database Gateway for DRDA in a heterogeneous environment. When attempting to call a stored procedure which has this feature enabled, through the gateway, the gateway will return an error, ORA-28526 or PLS-00201 (identifier must be declared).

Note:

This restriction applies to DB2 for MVS or z/OS as of V5.1 and DB2/UDB as of V8.1.

2.5.2 SQL Limitations

The SQL limitations are described as follows:

Oracle ROWID Column

The DB2 ROWID column is not compatible with the Oracle ROWID column. Because the ROWID column is not supported, the following restrictions apply:

  • UPDATE and DELETE are not supported with the WHERE CURRENT OF CURSOR clause. To update or delete a specific row through the gateway, a condition style WHERE clause must be used. (Bug No. 205538)

    When UPDATE and DELETE statements are used in precompiler and PL/SQL programs, they rely internally on the Oracle ROWID function.

  • Snapshots between Oracle database and DB2 are not supported.

    Snapshots rely internally on the Oracle ROWID column.

Oracle Bind Variables

Oracle bind variables become SQL parameter markers when used with the gateway. Therefore, the bind variables are subject to the same restrictions as SQL parameter markers.

For example, the following statements are not allowed:

WHERE :x IS NULL 
WHERE :x = :y 

CONNECT BY Is Not Supported

Oracle Database Gateway for DRDA does not support CONNECT BY in SELECT statements.

COUNT Function Compatibility

The following DRDA servers do not support all forms of the COUNT function, specifically COUNT(colname) and COUNT(ALL colname):

DB2 OS/390 V6,

The default for all DRDA server platforms is for all forms of COUNT to be passed to the DRDA server as it is.

If the gateway is to be used with one of the releases of DRDA servers, then it may be necessary to disable the default usage of this form of COUNT.

Refer to Chapter 4, "Mapping the COUNT Function" and Chapter 4, "Native Semantics" for details on how to disable or enable compatibility for these forms of COUNT.