This chapter describes release information specific to the 12c Release 1 (12.1) release of the Oracle Database Gateway for DRDA. It includes the following sections:
The following product components are included in the product installation media:
Oracle Database Gateway for DRDA, 12c Release 1 (12.1)
Oracle Net, 12c Release 1 (12.1)
The following sections describe the changes and enhancements unique to the 12c Release 1 (12.1) release of the gateway:
The Gateway Password Encryption tool (g4drpwd) has been replaced by a generic feature that is now part of Heterogeneous Services. Refer to Chapter 15, "Security Considerations" in Oracle Database Gateway Installation and Configuration Guide for IBM AIX on POWER Systems (64-Bit), Linux x86-64, Oracle Solaris on SPARC (64-Bit), Oracle Solaris on x86-64 (64-Bit) and HP-UX Itanium or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows for details.
This feature allows the gateway to optionally run in CHAR Semantics mode. Rather than always describing UDB CHAR columns as CHAR(n BYTE), this feature describes them as CHAR(n CHAR) and VARCHAR(n CHAR).
This feature optionally suppresses the ratio expansion from UDB database to Oracle database involving multi-byte character set.
Besides full IPv6 support between Oracle databases and the gateway, IPv6 is also supported between this gateway and UDB databases.
You can optionally choose to terminate long idle gateway sessions automatically with the gateway parameter HS_IDLE_TIMEOUT.
This release provides support for UDB stored procedures, which return result sets.
Refer to Oracle Database Gateway Installation and Configuration Guide for IBM AIX on POWER Systems (64-Bit), Linux x86-64, Oracle Solaris on SPARC (64-Bit), Oracle Solaris on x86-64 (64-Bit) and HP-UX Itanium 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.
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. 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.
The following restrictions are known to exist for the products in the 12c Release 1 (12.1). Restrictions are not scheduled to change in future releases. Refer to Chapter 4, "Developing Applications", for information or limitations when developing your applications.
The following considerations exist in the 12c Release 1 (12.1):
The SUBSTR function can be used with the Oracle database in ways that are not compatible with a DRDA server, such as DB2 UDB for z/OS. 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.
Refer to "DRDA Data type to Oracle Data type Conversion" for detailed information about data types.
Null values are not passed into, or returned from, calls to stored procedures through the gateway.
DB2 Universal Database does not support string concatenation of numbers. For example,
SELECT 2||2 FROM table@dblink
is not allowed.
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 Oracle Database Gateway Installation and Configuration Guide for IBM AIX on POWER Systems (64-Bit), Linux x86-64, Oracle Solaris on SPARC (64-Bit), Oracle Solaris on x86-64 (64-Bit) and HP-UX Itanium or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows , depending on your platform, for more information.
The gateway utilizes a package for statement execution. This package will be implicitly bound upon the first time the gateway connects to the target DB2 system. Ensure that the user ID connecting to the DB2 system has the necessary privileges to bind a package. Refer to Oracle Database Gateway Installation and Configuration Guide for IBM AIX on POWER Systems (64-Bit), Linux x86-64, Oracle Solaris on SPARC (64-Bit), Oracle Solaris on x86-64 (64-Bit) and HP-UX Itanium or Oracle Database Gateway Installation and Configuration Guide for Microsoft Windows , depending on your platform, for more information.
In general, the following types of SQL expression forms do not work correctly with the gateway because of DB2 limitations:
date + number number + date date - number date1 - date2
DB2 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 DB2 where they are rejected.
Also, DB2 does not perform date subtraction consistently. When you subtract two dates (date1 - date2), differing interpretations of date subtraction in DB2 cause the results to vary by server.
Note:
Avoid date arithmetic expressions in all gateway SQL expressions until date arithmetic problems are resolved.Because of a restriction of the DRDA architecture, rows with aggregate length exceeding 32 KB in DRDA representation cannot be stored or retrieved.
SQL*Plus cannot fetch LONG columns from the Oracle Database Gateway for DRDA.
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, the Oracle Database Gateway for DRDA does not support this feature in a heterogeneous environment. When attempting to call a stored procedure that has this feature enabled, through the gateway, the gateway will return an error, ORA-28526 or PLS-00201 (identifier must be declared).
The SQL limitations for Oracle Database Gateway for DRDA are described in the following sections:
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 Copying Data from Oracle Database to DRDA Server, for more information.
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 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