UL/DB2
Introduction
The User Language/DATABASE 2 Interface (UL/DB2) provides a multithreaded connection from a Model 204 User Language procedure to a DB2 database to retrieve DB2 data or manipulate DB2 tables.
See installing the UL/DB2 interface for details on installing UL/DB2.
The UL/DB2 topics provide information for these users:
| User | Responsible for... |
|---|---|
| Model 204 system managers | Making a Model 204 environment ready to support the interface, and defining and controlling security. System managers should know how to set up Model 204 Online and BATCH204 environments. |
| DB2 database administrators | Granting PLAN and table privileges. DB2 database administrators should know how to precompile and bind a PLAN, and grant access to a PLAN. |
| Application programmers | Developing User Language procedures that use embedded SQL statements. Application programmers should know User Language and SQL syntax. |
Overview
The User Language/DATABASE 2 Interface (UL/DB2) allows a Model 204 User Language procedure to use embedded SQL statements to access a DB2 database. User Language becomes, in effect, a host language for DB2. SQL statements embedded in a User Language procedure can update a DB2 database or return selected values from DB2 to Model 204.
The following example is an SQL statement embedded in a User Language procedure:
EXEC DB2 DECLARE BAR CURSOR FOR SELECT CHA FROM DVPJB.TEST2 END EXEC
UL/DB2 program environment
The following figure shows the UL/DB2 program environment under IBM z/OS.
UL/DB2 program environment
Requirements
The requirements for the User Language/DATABASE 2 Interface are:
- IBM z/OS 1.01 or higher
- Model 204
- DATABASE 2 Version 2 Release 1 or higher
- To use a Model 204 user ID as the DB2 authorization ID, the Model 204 security interface for ACF2 must be installed.
Supported operating systems
UL/DB2 runs under only IBM z/OS. It does not run under IBM z/VM or IBM z/VSE operating systems.
Accessing DB2 address spaces
Model 204 uses the Call Attach Facility (CAF) to communicate with a single local DB2 subsystem that is on the same physical machine as Model 204.
However, this local DB2 subsystem can use the DATABASE 2 Distributed Data Facility (DDF) to communicate with one or more remote DB2 databases. These remote databases can be on the same CPU as the local database or on a different CPU.
Limitations
The following limitations apply to the UL/DB2 Interface:
- The UL/DB2 Interface is for only z/OS DB2.
- The JCL to run Model 204 must include DSNvrm.DSNLOAD in the STEPLIB in order to load DSNALI and DSNTIAR, unless the module is in the Link Lookaside Area.
- The UL/DB2 Interface is for a single machine implementation.
- There is no support for singleton SELECT statements, although singleton SELECT statements can be issued using the $SPIFY function.
- There are no system manager commands to control the subtasks.
- The number of threads, or subtasks, is defined statically.
- The Model 204 address space can have a link open to only one local DB2 subsystem.
- A maximum of ten cursors can be open simultaneously.
UL/DB2 topics
The UL/DB2 documentation consists of the pages listed below. This list is also available as a "See also" link from each of the pages.