Access to IMS Through DBCTL

In this section:

IMS offers the DBCTL (Database Control) facility for accessing online IMS databases. DBCTL provides a number of security, efficiency, and application control enhancements and is easy to implement.

This section includes the following topics:


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Advantages of DBCTL

The advantages of using DBCTL include the following:

DBCTL must have been installed as described in Installation Instructions.


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Invoking the Adapter in the DBCTL Environment

The following diagram illustrates the relationship between FOCUS, the adapter, and IMS in the DBCTL environment:

Address Space

Contains

1

  • FOCUS.
  • The Adapter for IMS/DB.
  • The DBCTL stub, a component of IMS.

2

  • The online IMS databases.

To invoke the adapter interactively within the DBCTL environment, edit the following CLIST to conform to the standards at your site. In addition, add the IMS.RESLIB and the name of the PDS that contains the DRA Startup Table (load module DFSPZPxx, described in Installation Instructions) to the STEPLIB allocation in your TSO logon procedure. Note that the CLIST allocates the entire FOCPSB data set, not just one member:

PROC 0
CONTROL NOMSG
FREE DDNAME(USERLIB ERRORS MASTER ACCESS FOCEXEC FOCPSB FOCLIB)
ALLOC F(ERRORS)   DA('prefix.ERRORS.DATA') SHR REUSE
ALLOC F(USERLIB)  DA('prefix.IMS.LOAD' +
                     'prefix.FUSELIB.LOAD') SHR REUSE
ALLOC F(MASTER)   DA('prefix.MASTER.DATA') SHR REUSE
ALLOC F(ACCESS)   DA('prefix.ACCESS.DATA') SHR REUSE
ALLOC F(FOCEXEC)  DA('prefix.FOCEXEC.DATA') SHR REUSE
ALLOC F(FOCPSB)   DA('prefix.FOCPSB.DATA') SHR REUSE
ALLOC F(FOCLIB)   DA('prefix.FOCLIB.LOAD') SHR REUSE
CALL 'prefix.FOCLIB.LOAD(FOCUS)'

where:

prefix

Is the high-level qualifier for your FOCUS production libraries.

You can omit the allocation for ddname ACCESS if you select the PSB name with the IMS SET PSB command, not in an Access File (see Implementing DBCTL).

To invoke the adapter as a batch job, submit the following JCL after editing it to conform to the standards at your site and adding a JOB card. Note that the JCL allocates the entire FOCPSB data set, not just one member:

//FOCDBCTL EXEC PGM=FOCUS,REGION=nn 
//STEPLIB  DD DSN=prefix.FOCLIB.LOAD,DISP=SHR
//         DD DSN=IMS.RESLIB,DISP=SHR
//         DD DSN=prefix.IMS.LOAD,DISP=SHR
//         DD DSN=prefix.FUSELIB.LOAD,DISP=SHR
//ERRORS   DD DSN=prefix.ERRORS.DATA,DISP=SHR
//FOCPSB   DD DSN=prefix.FOCPSB.DATA,DISP=SHR
//FOCEXEC  DD DSN=prefix.FOCEXEC.DATA,DISP=SHR
//MASTER   DD DSN=prefix.MASTER.DATA,DISP=SHR
//ACCESS   DD DSN=prefix.ACCESS.DATA,DISP=SHR
//SYSOUT   DD SYSOUT=*
//*FSTRACE  DD SYSOUT=*,DCB=BLKSIZE=133
//*FSTRACE4 DD SYSOUT=*,DCB=BLKSIZE=133
//SYSPRINT DD SYSOUT=*
//SYSIN    DD *
TSO IMS SET IMSPZP xx 
TSO IMS SET DBCTL ON
TSO IMS SET PSB psbname 
TABLE FILE ...
  .
  .
  .
END
FIN
/*
//

where:

nn

Is the region size.

prefix

Is the high-level qualifier for your FOCUS production libraries.

xx

Is the suffix for the DRA Startup Table, chosen during installation (see Installation Instructions).

psbname

Is the name of the PSB to use.

Note:


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Implementing DBCTL

To implement the DBCTL environment, issue the following commands in the order shown:

ENGINE IMS SET IMSPZP {xx|00}
ENGINE IMS SET DBCTL ON

where:

xx

Indicates the suffix for the DRA Startup Table, chosen during installation (see Installation Instructions). The default is 00.

Next, if you did not create an Access File to automatically select the PSB for your request (see Creating FOCUS Descriptions), or to change the selected PSB, issue the following command either from the command line or in a FOCEXEC

ENGINE IMS SET PSB psbname 

where:

psbname

Is the name of the FOCPSB library member to use. This name must be identical to the name of the actual PSB that IMS will access. If the member does not exist, the following error message is generated:

(FOC4261) FOCPSB MEMBER NOT FOUND: psbname

Note:

To see the settings in effect at any time during your session, issue the following query command:

ENGINE IMS SET ?

Release Dependent Adapter Features contains an example of the IMS SET ? query command.


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