Comments on: Chain function to find a specific record

By: tomliotta

tomliotta — Wed, 11 Apr 2012 20:08:43 +0000

Again, be aware that CHAIN will only find one record that matches the two keys. In order to check other records that also match the same two key values, you can issue READ or READE statements in a loop. The CHAIN will position to the first record that matches; the reads will retrieve records that follow the first.

Your program would test each record to ensure that you process only the ones you want.

Tom

By: giugia

giugia — Wed, 11 Apr 2012 13:40:47 +0000

Thanks a lot to both of you (is it correct english?!?!?! I hope so!)
I resolved with the BigKat’s solution! In this case the 1st two fields was enaugh for found my record!

By: charliebrowne

charliebrowne — Wed, 11 Apr 2012 12:52:03 +0000

You said you want a specific record, but only know 2 of the 4 key fields, how will you know if you have the correct record.
If the 1st two fields of the key are unique, BigKats answer is correct.
If they are not, then are the two fields you want to use unique to the file. If so, create a new access path using those fields.

By: bigkat

bigkat — Wed, 11 Apr 2012 12:42:30 +0000

you can chain by partial keys, but they must be the first fields in the key. That is, if the key consists of: fld1, fld2, fld3, fld4 you can chain with:

fld1, fld2, fld3, fld4
fld1, fld2, fld3
fld1, fld2
fld1