ALLOCATION OF DATABASE DD STATEMENTS FROM JCL, DBRC and MDALIB.

Document ID : KB000053847
Last Modified Date : 14/02/2018
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Description:

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

Solution:

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.