What is the difference between DBKEY and CALC in IDMS

harkar · New User Joined: 11 Nov 2006 Posts: 5

senthilarumugam · New User Joined: 09 May 2006 Posts: 8 Location: chennai

DBKEY, the database key is used to find and get the record from the database. It will have the Page number and line index number of the record. Whenever the OBTAIN CALC command is passed, this particular CALC key will converted to its equivalent page number(DBKEY) and the record will be retrieved.

correct me if i am wrong! expecting more comments!

honestbharani · New User Joined: 23 Nov 2006 Posts: 1 Location: chennai

CALC uses one (or more) of the record fields as the key. The DB KEY uses the combination of page number and line number. Am I right?

senthilarumugam · New User Joined: 09 May 2006 Posts: 8 Location: chennai

Yes. this conversion of CALC key to the DBKEY(page No + line index No) is done using some internal process

mfarien · New User Joined: 02 Mar 2007 Posts: 17 Location: USA

I am not sure weather CALC will use DBKEY to get the record.
For CALC storage and retrieval :
When the application program requests that record occurrences be stored into the database, IDMS/R uses the CALC-key value to calculate the page into which the record should be placed. IDMS/R uses a randomizing routine to distribute records evenly over its area. To retrieve a record later, the application program supplies IDMS/R with a CALC-key value, and IDMS/R uses the randomizing routine to locate the proper page and directly retrieve the record occurrence that has the supplied CALC-key value.
The randomizing unit make out the CALC and Hashing mechanism.