Can we define same PSB more than one application programs

yadagiri_p · New User Joined: 11 Sep 2005 Posts: 9 Location: bangalor

Hi

Can we define same PSB more than program?

pls explain briefly.

regards
yadagiri

smiley_u · New User Joined: 05 Oct 2005 Posts: 2

Hi,
PSB is nothing but group of segments from one or more physical databases required by an application program.These segments are combined to create a new hierarchical structure.This is done by defining a control block called Program Specification Block (PSB). Each PSB consists of one or more Control Blocks called Program Communications Block (PCB).
Each PSB supplies IMS with a description of what database info (which db segments) may be accessed by the application program.

While many programs can share the same PSB, programs can use only 1 PSB in a given application. This is because there are so many situations where more than 1 application program require the same logical hierarchical structure.

Assume, we have company details and employee details in a PSB called COMPPSB. We have 2 different programs, of which one prints a report of the various CMM level-5 companies and the other prints a list of employees with mainframe skills, both have to access the same PSB-COMPPSB.

On the otherhand if there were 2 different PSBs namely COMPANY and EMPLOYEE and a single application program needs to access details from the above 2 PSBs, then it is not possible. We would be able to give the name of a single PSBLIB only in the JCL calling the application program.

Hope this helps......

vijayamadhuri · Active User Joined: 06 Apr 2005 Posts: 180

No it is not possible.

Each program should have it own psb defined.

A psb is nothing but granting certail priveleages to the program.. saying that program can access only those segments and those databases

itssreehere · New User Joined: 10 Jan 2006 Posts: 65 Location: chennai

It's possible. many programs can access one PSB.

PSB is nothing but application programs view of physical DB.Some thing like( or more) view in DB2. Based on the PSB one application pgm can view all the segments or only some segments in the physical DB. Even we can hide some fields from the application by defining appropriatly in PSB.
Also it provides different privileges to application pgm. ex. delete,update,retrieval or all privilages.

Bitneuker · Posted: Wed Jan 11, 2006 5:40 pm

Yes it can. Agree with itssreehere. The only consequense for programs using the same PSB is they are restricted to the access and privilages defined in the PCB's. Programs can only access databases that are defined in the PSB by the PCB's and within these PCB's to the rights like sensitive segments, sensitive fields and processing options. Each program can use only one PSB (that's why its called program specification block). This situation occurs but there is a risk that, if a specific PSB is modified other programs using this PSB (by name) not being adjusted to this modified PSB malfunction.