Server Guide

Setting up the database and your application's access

To test your DL/I calls, you must first define the database segments and your application's access to those segments. This definition must be done on Micro Focus Workbench if you plan to test your application on the workstation and on IMS/ESA. For more information about setting up your databases to test DL/I calls on the workstation, see MVS Workbench Micro Focus Workbench for MVS Programmers.

Building the DBDs and PSBs

For an application to communicate with the database without being aware of the physical location of the data, use database descriptors (DBD) and program specification blocks (PSB).

A DBD describes the content and hierarchical structure of the physical or logical database. DBDs also supply information to IMS to help it locate segments.

A sample DBD follows:

DBD    NAME=MYBANKD,ACCESS=(HIDAM,VSAM)                             
DATASET DD1=MYBANKD,DEVICE=3390                                     
SEGM   NAME=CUSTOMER,PARENT=0,BYTES=179                              
FIELD  NAME=(ACCTNO,SEQ,U),BYTES=10,START=1,TYPE=C                   
LCHILD NAME=(INDEX,MYBANKI),PTR=INDX                                
SEGM   NAME=CHECKING,PARENT=CUSTOMER,BYTES=25                        
SEGM   NAME=CHECKACT,PARENT=CHECKING,BYTES=26                        
SEGM   NAME=SAVING,PARENT=CUSTOMER,BYTES=25                          
SEGM   NAME=SAVACT,PARENT=SAVING,BYTES=26                            
DBDGEN                                                               
FINISH                                                               
END                                                                  

A PSB specifies the database segments an application can access. PSBs are composed of one or more program control blocks (PCB), because an application can access multiple databases. In addition to including the segments of data an application can access, the PSB also describes the functions an application can perform on the data, such as read only, update, or delete.

A sample PSB follows:

 TITLE 'PSB FOR IMS TEST CASE 4'                                     
   PCB   TYPE=TP,PCBNAME=ALTPCB1,LTERM=TERM123
   PCB   TYPE=DB,PCBNAME=BANKPCB1,DBDNAME=MYBANKD,PROCOPT=AP,KEYLEN=10
   SENSEG NAME=CUSTOMER,PARENT=0                                       
   SENSEG NAME=CHECKING,PARENT=CUSTOMER                                
   SENSEG NAME=CHECKACT,PARENT=CHECKING                                
   SENSEG NAME=SAVING,PARENT=CUSTOMER                                  
   SENSEG NAME=SAVACT,PARENT=SAVING                                    
   PSBGEN LANG=,PSBNAME=PSBBANK4                              
  END


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