Oracle: Insertion on an indexed table, avoiding duplicates. Looking for tips and advice.
- by Tom
Hi everyone,
Im looking for the best solution (performance wise) to achieve this.
I have to insert records into a table, avoiding duplicates.
For example, take table A
Insert into A (
Select DISTINCT [FIELDS] from B,C,D..
WHERE (JOIN CONDITIONS ON B,C,D..)
AND
NOT EXISTS
(
SELECT * FROM A ATMP WHERE
ATMP.SOMEKEY = A.SOMEKEY
)
);
I have an index over A.SOMEKEY, just to optimize the NOT EXISTS query, but i realize that inserting on an indexed table will be a performance hit.
So I was thinking of duplicating Table A in a Global Temporary Table, where I would keep the index. Then, removing the index from Table A and executing the query, but modified
Insert into A (
Select DISTINCT [FIELDS] from B,C,D..
WHERE (JOIN CONDITIONS ON B,C,D..)
AND
NOT EXISTS
(
SELECT * FROM GLOBAL_TEMPORARY_TABLE_A ATMP WHERE
ATMP.SOMEKEY = A.SOMEKEY
)
);
This would solve the "inserting on an index table", but I would have to update the Global Temporary A with each insertion I make.
I'm kind of lost here,
Is there a better way to achieve this?
Thanks in advance,
