When to use cursor?



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When to use cursor?

Postby sunilkumar1244 » Thu Aug 13, 2009 6:43 pm

Hello,

Can anyone please tell me in detail when to use cursor.
While using cursor when to use single fetch and when to use multifetch.

Thanks.
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Re: When to use cursor?

Postby GuyC » Thu Aug 13, 2009 7:16 pm

it's more a db2 question then a cobol question.

Cursor vs single select : If you're select returns more than one row (and you need those rows), you'll have to use a cursor.
If you only need the first one (but you're not allowed to "order by") you could use a single select with "fetch first 1 row only".

Cursors :
Multi-row fetching is more performant then single row fetching,but it complicates your program a bit.
Once you have a decent skeleton or example program its easy.

If you expect to do more then 1000 fetches, i would advise to certainly switch to multi-row.
But even for smaller cursors : once you're used to it : always use it.

if you google "multi-row fetch" you'll find all kind of interesting articles.

one being : http://it.toolbox.com/blogs/db2zos/why- ... cool-12229
I can explain it to you, but i can not understand it for you.
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