Re: sql question
In article <66hkm2$42m@cssun.mathcs.emory.edu>,
johnl@informix.com (Jonathan Leffler) wrote:
> ...
> That's a complicated way of writing:
>
> BEGIN WORK;
> SELECT DISTINCT * FROM Table INTO TEMP Temp1;
> DELETE FROM Table WHERE 1 = 1;
> INSERT INTO Table SELECT * FROM Temp1;> COMMIT WORK;
>
> This is a reasonable solution for small to medium tables when you have
> enough disk space available for the whole temporary table.
> ...
Never done this kind of stuff but it might be faster to do something
along the lines of:
BEGIN WORK;
CREATE TABLE NewTable (...);LOCK TABLE NewTable IN EXCLUSIVE MODE;
INSERT INTO NewTable SELECT DISTINCT * FROM OldTable;
DROP TABLE OldTable;RENAME TABLE NewTable TO OldTable;
CREATE INDEX ...;
COMMIT WORK;
Not as generic but may be better in some circumstances.
----------------------------------------------------------------------
John H. Frantz Power-4gl: Extending Informix-4gl
frantz@centrum.is http://www.rl.is/~john/pow4gl.html
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