Is PRE-SELECT more powerful than FOR EACH?

[TomBascom]

One more clarification is required, can you please let me know if PRE-SELECT statement is more powerful that FOR-EACH. Is it that PRE-SELECT statement improves performance than FOR-EACH? Correct me if I am wrong.

No, it is not "more powerful". It just gives you a different set of capabilities.

Personally, I never use PRE-SELECT. But some people find it useful. Particularly if they are planning to modify the key fields in such a way that they will see a record two or more times in the FOR EACH loop. Like this might:

/* renumber customers:
 * current customers have 5 digit cust-nums and we want to
 * convert to 6 digit customers that start with 1.
 */

for each customer:
  cust-num = cust-num + 1000000.
end.

/* this doesn't actually work ;) */

 

[saravanakumar]

Thanks a lot... I got the answer... :yippee: