ALLOCATION OF DATABASE DD STATEMENTS FROM JCL, DBRC and MDALIB

Products

• Database Organizer for IMS for z/OS
• Database Organizer (IMS Tools)
• DATABASE MANAGEMENT SOLUTIONS FOR IMS FOR Z/OS

Issue/Introduction

How does Database Organizer (DBO) allocate Database DD statements from JCL, DBRC RECON datasets and Dynamic Allocation Library (MDALIB)?

Resolution

The following conditions apply for DBO to select the Database DD statement(s) either from the JCL, or from DBRC RECON, or from IMS MDALIB:

1. DD statement always will be used from JCL if it is coded here                                     
    - (neither DBRC nor MDALIB will be checked)                 
                                                                
2. DD statement will be used from DBRC                          
    - if NOT coded in the JCL                                      AND    
    - if option DBRC=Y is used                                     AND    
    - if DD statement is defined in the RECON dataset           
                                                                
3. DD statement will be used from MDALIB                        
    - if NOT present in the JCL                                    AND    
    - if MDA member is present in the MDALIB                       AND    
    - if option DBRC=Y, but DD statement NOT in RECON              OR       
    - if option DBRC=N and DBALLOC=Y           

The job abends with database allocation error in all other cases.