Working With CA Datacom CICS Services
Information about working with CA Datacom CICS Services.
CA Datacom CICS Services make it possible for application programs which run under CICS/TS to communicate with
CA Datacom®/DB. The main purpose of
CA Datacom® CICS Servicesis to provide the interface between CICS/TS and the
CA Datacom®/DBMUF. This applies to both user application programs and the online components of such CA products as Sysview,
CA Dataquery™ for CA Datacom®, and
CA Datacom® Datadictionary™. Application programs and User Requirements Tables (URTs) using
CA Datacom® CICS Servicescan reside above or below the 16 MB (megabyte) line. Details about using your applications with
CA Datacom® CICS Servicesare provided in Linking Application Programs
Download a PDF of Working with CA Datacom CICS Services.
CA Datacom® CICS Servicesprovide the following features:
Supports Various Languages
Application programs can be written in the following languages:
- CA Ideal
- COBOL (with or without the use of CA MetaCOBOL+)
- PL/I using a command-level interface to CICS/TS
- JAVA support for Record-At-A-Time API
- JDBC API support usingCA Datacom® Server
Selects URT for Executing Application
CA Datacom®/DBenvironment, it is the URT associated with the program that communicates all program-specific information to
CA Datacom®/DB, such as the following:
- With which MUF (in a multiple MUFs environment) requests using this URT are processed
- Which tables the application can access and update
- Whether transaction backout is made available for any abending update transactions to the listed tables
- The relative priority within the MUF for the program-issued requests
CA Datacom®/DBrequires every executing program to be associated with a URT. In batch, you determine which URT a given program is to use. Under CICS,
CA Datacom® CICS Serviceshandles the association of a URT with your application program for you. You define several URTs from which
CA Datacom® CICS Servicesmakes a selection at execution time, depending on the database and table in which the requested data resides, and optionally (in a multiple MUFs environment) which MUF is to process the request.
Connects and Disconnects MUFs
To use system resources effectively under CICS,
CA Datacom® CICS Servicesperforms connect and disconnect functions. The DBCSID macros specify how and when CICS Services connects to each MUF. All MUFs are disconnected during CICS Services shutdown. You can specify general exceptions through the DBCSID macro appended to the System Generation Options Table (DBCVTPR). Or, you can explicitly invoke connect or disconnect at anytime through online commands. In the DBCSID macros, you can specify that MUFs are connected:
- Only when their use is required
- Only when you enter an online command to request connect
If no DBCSID macro is coded, connect is done at PLT time.
Opens and Closes URTs
To use system resources effectively under CICS, the Open and Close functions are performed by
CA Datacom® CICS Services. Unless you specify otherwise,
CA Datacom® CICS Servicesopens all URTs at CICS startup and closes all URTs at CICS shutdown. You can specify general exceptions through the System Generation Options Table (DBCVTPR). Or, you can explicitly invoke an open or close at anytime through online commands. In DBCVTPR, you can list URTs to be opened only when their use is required or only when you enter an online command to request the open.
Manages Allocated Threads
CA Datacom®/DBallows applications to use multiple URTs through an extended request technique.
CA Datacom® CICS Servicesuses this technique without requiring the CICS application programmer to code extra logic. A CICS application program can be coded with the same call request format as a batch program. The extended request logic allocates for CICS usage several processing threads to
CA Datacom® CICS Servicesobtains and releases the allocated threads as required. This allows multi-threading of application requests. The multi-thread logic permits concurrent processing of several CICS transactions.
Update requests require sole use of a single thread.
CA Datacom® CICS Servicesoptimizes thread use by placing multiple read-only transactions on the same thread, thus reserving additional threads for transactions performing update requests. Once processing on a reserved thread is complete,
CA Datacom® CICS Servicescommits resources automatically.
Extends CICS Processing Functions
CA Datacom® CICS Servicesprovides other functions related to CICS processing. CICS provides a trace function for CICS activities, transaction backout of abending tasks, and SYNCPOINT processing.
CA Datacom® CICS Servicesextends these CICS functions to the
CA Datacom®/DBprocessing environment as follows:
- Provides a before and after CICS trace entry on each database request. See CICS Trace Table Entries.
- Invokes aCA Datacom®/DBbackout for any task which updates a database, but abends before completion.
- Issues aCA Datacom®/DBcheckpoint to the appropriate MUF or MUFs when a transaction issues a CICS SYNCPOINT. For details on techniques for improving the operating efficiency of your online applications, see Updating Technique.
Supports User Exits
CA Datacom® CICS Servicesprovides facilities for implementing two user exits, one before
CA Datacom® CICS Servicesissues a
CA Datacom®/DBcall, and one both before and after accessing
CA Datacom®/DB. You can use these exits to tailor
CA Datacom® CICS Servicesto the requirements of your site.
For more information about the requirements for these exit programs, see Using Exit Programs.
Displays System Resources on Request
You can monitor system resources at anytime by issuing an online inquiry command to display a selected resource.
CA Datacom® CICS Servicesdisplays the requested information in a formatted panel or in scrollable form, depending on the transaction ID.
CA Datacom® CICS Servicesis installed with the following CICS transaction IDs for issuing online commands to monitor system resources:
- DBEX DBECThe inquiry command invokes a scrollable display of MUFs or URTs and, if requested, the tables that are listed in each URT. In an MRO environment and a CICSPLEX, the display can be limited to MUFs or URTs in a specified CICS, or extend to MUFs or URTs in all CICS systems, or a range of CICS systems.
- DBIC DBOCTwenty inquiry commands are available to invoke formatted displays of the following resources and data:
- URTs, with or without associatedCA Datacom®/DBtable information
- Trace table, either scrollable display of entries, criteria on which trace is based, or status of Auxiliary Trace
- Statistics: Active tasks, held transactions, abending tasks, concurrent users, requests by return code
- Options currently in use (defined through System Option Table (DBCVTPR) parameter values)
- Software maintenance level
- DBUTDisplays storage areas for CICS programs and system tables at specified locations.
Controls System Resources on Request
If authorized for the required transaction ID, you can alter system resources by issuing the appropriate online command.
CA Datacom® CICS Servicesdisplays messages on the command results.
CA Datacom® CICS Servicesis installed with the following CICS transaction IDs for issuing online commands to alter system resources:
- DBECThe scrollable display that an INQuire command invokes contains fields which are updatable when the command is issued through DBEC. Also, several PERform commands invoke actions which alter MUF or URT resources within the local or remote CICS systems and startup/shutdown in the local or remote CICS systems.
- DBOCTwenty-four commands permit you to modify or control:
- CA Datacom®/DBtables
- CA Datacom® CICS Servicesmodules or control tables
- Trace Facility and Auxiliary Trace Facility
- CA Datacom® CICS Servicesoperation and options
- DBUTAllows you to alter CICS programs and system tables.
Facilitates Application Development
CA Datacom® CICS Servicesfacilitates application development with the following:
- DBTXAccepts read-only requests toCA Datacom®/DB, allowing you to examine command syntax or simulate program logic.
- DBTSAccepts read-only and update requests toCA Datacom®/DB, allowing you to examine command syntax or simulate program logic and also update the specified database.
- DBUGInterceptsCA Datacom®/DBrequests issued by an executing application program, allowing you to examine its processing.
Provides Means of Restricting or Extending Inquiry and Control
CA Datacom® CICS Servicesprovides multiple transaction IDs through which the security administrator can restrict the use of control commands to authorized users.
- Three alternate CICS transaction IDs are provided to enable the security administrator to authorize users to invoke inquiry displays while limiting their access to control commands. Specifically, the security administrator can authorize a limited set of users the access to Operational (DBOC), Enhanced (DBEC) and Test Facility (DBTS) transaction IDs which are valid with commands which allow the control of resources. The security administrator can provide unrestricted access to the Inquiry (DBIC), Enhanced Inquiry (DBEX), and Test Facility Read-Only (DBTX) transaction IDs which can be used only with "inquiry" type commands.
- A means of limiting authorized users for the DBOC transactions to initiate/terminateCA Datacom® CICS Servicesor alter online the System Generation Options that are coded in DBCVTPR is provided. This limiting is accomplished through use of the MSTOPR= parameter in the System Options Table, which accepts up to 50 operator IDs.
Provides Security for Database Access
To promote the security of database access,
CA Datacom® CICS Servicespasses
CA Datacom®/DBthe following with each
- User identification: Either the 3-byte operator ID or the 8-byte operator name from the CICS sign-on table (CESN OPERID or CESN USERID), depending on your specifications.CA Datacom®/DBsecures access and update toCA Datacom®/DBtables, record, fields, and elements based on the ID of the request initiator. If you have CA Top Secret or RACF from IBM, these security products provide the ACEE address toCA Datacom® CICS Services.
- CA ACF2 supplies the eight-byte USERID to the CESN USERID field, if available. Otherwise, your DFHSNT entry is used.