Difference between Chain and Setll reade
- The CHAIN command does a SETLL and a READE in order to find a match. CHAIN is best used to locate a unique record (like a customer record).
- SETLL with READE is best used when there can be more than one record found. For example, you can find multiple customer orders in your system for one unique customer.
Setll (Field1 : Field 2) FileName;
Read FileName;
Dow Not %EOF(FileName);
//Some Logic
Reade FileName;
Enddo;
Chain ( parm_DS.Nbr
: parm_DS.Seq) // Keys
filename // File
ds_filename_IO; // Input DS
If %found(filename);
parm_filename_DS = ds_filename_IO;
Success = *On;
Endif;
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