Linking logically related data

A file contains different LREC types. The contents of an LREC depend on the LREC ID, as follows:

LREC ID

Contents of LREC

X'80'

Surname and first name

X'90'

Address

X'A0'

Salary details

X'B0'

Telephone number, and so on.

Generally, information is requested by type rather than specifically (for example, by name, address, or telephone information). However, there must be a unique link connecting the address, salary, and telephone information to the name. To make this link, you could use a unique value based on the person’s name. However, this would waste space because you would have to repeat the value for all LREC types (90, A0, B0) related to a particular name.

The TPFDF product supports a unique key generator that returns a unique value for a file. You can store this value in LRECs that are related to each other. The unique key can define relationships in a file, between files, between subsystems, between systems, and between companies.

The unique key is a 4-byte hexadecimal value.

&SW00OP3 SETC '.......1'

To hold the unique key, you must define a 4-byte field in each LREC.

No changes are necessary if the changes are made in the DSECT macro.

In this example, a subfile is created. Name, address, and salary records are then added:

     DBOPN REF=zzzzzz,HOLD
      DBUKY REF=zzzzzz

                      TPFDF puts the unique value in field SW00UKY

To set up the LREC (including size and primary key fields):

     MVC  zzzzUKY,SW00UKY
                      Insert the unique key value into the LREC

      DBADD REF=zzzzzz,KEY1=(PKY=#zzzzK80,UP)