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Jun 03, 2016 at 08:45 PM

Question about using the UNLOAD statement

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Hi,

I have a relatively large database I need to rebuild from scratch. I can't use the dbunload utility because the database is corrupt, so I have to go table by table.

I also thought that since I have to do this, that I should take this oportunity to trim the database and copy only relevant data. So I thought about using the UNLOAD statement to export a subset of the data.

For example, the table "iTrans":

UNLOAD SELECT * FROM iTrans WHERE TransDate >= '2014-01-01' TO '\\transfer\itrans.dat";

This works perfect. The problem is with "iTrans" child table "iTransRow". The primary key is a two column key (IdLoc, IdSeq).

HOW do I filter the rows in "iTransRow" to only contain those that are in the "iTrans" subset? If the the primary key was a single column it would be easy using the IN clause, but with a two column key?

I came up with this, but I think I'm pretty sure there must be a better way...

UNLOAD SELECT * FROM iTransRow

WHERE

EXISTS (SELECT * FROM iTrans AS A WHERE A.Fecha >= '2014-01-01' AND iTransRow.IdLoc=A.IdLoc AND iTransRow.IdSeq=A.IdSeq)

TO '\\transfer\itransrow.dat'

These are fairly large tables, and I need to rebuild this asap 😔

Thanks for any ideas,

Edgard