Explain db2 precompiler process

karthi_ind · Posted: Sun Jun 06, 2004 3:37 pm Post subject: Explain db2 precompiler process

hi

if my interviewer asks explain db2 precompiler process.
whatz the answer? Can anyone explain in detail,
explain each process (bind, package, collection)

bye

anbudan
karthi G.

harikrishnanrajeev · EXPERT Joined: 28 Jan 2004 Posts: 40 Location: Trivandrum

Hello friend,

Here am trying to explain the DB2 - cobol process. The first stage is the precompilation step where the cobol program with the embedded SQL will be modified to form the modified source code and also the DBRM. The DBRM contains the sql statements. The timestamp is also alloted here, the information remains with both DBRM and the modified source code. In the modified source code the sql statemements will be replaced by call to DSNHLI statements with some 5 parameters. These are

1. The DBRM name.
2. SQL statement numbers.
3. The timestamp information.
4. Address info of SQLCA
5. Address info of host variables.

The DBRM undergoes the bind process and package is created. The package is not an executable so we make use of plan. The plan contains pointers to packages.

The modified source code is compiled , link edited to form load module. Then the timestamp is matched with the info in package. If mismatch is there we get timestamp mismatch error and rebind has to be done with proper DBRM.

here i have given just a rough idea abt the process. Pls do read some books for better clarity.

corrections are welcome

regards

Hari.

nandini · New User Joined: 27 Feb 2004 Posts: 18

Hi Hari

If we are changing the modified source program and we are not binding it what will happen? And in a case i m not changing the progm and again binding what will happen? Here in which case the timestand mismach will occur?

Can pls explain?

Nandini

anuradha · Global Moderator Joined: 06 Jan 2004 Posts: 257

hello nandini,

if you are modifying the program and if you are not binding it, you will get a timestamp mismatch error.

Thanks,
Anu