Re: faster INSERT with possible pre-existing row?

Insert into a temp table then use INSERT INTO...SELECT FROM to insert
all rows into the proper table that don't have a relationship.

Chris

Dan Harris wrote:
> I am working on a process that will be inserting tens of million rows
> and need this to be as quick as possible.
>
> The catch is that for each row I could potentially insert, I need to
> look and see if the relationship is already there  to prevent  multiple
> entries.  Currently I am doing a SELECT before doing the  INSERT, but I
> recognize the speed penalty in doing to operations.  I  wonder if there
> is some way I can say "insert this record, only if it  doesn't exist
> already".  To see if it exists, I would need to compare  3 fields
> instead of just enforcing a primary key.
>
> Even if this could be a small increase per record, even a few percent
> faster compounded over the whole load could be a significant reduction.
>
> Thanks for any ideas you might have.
>
> -Dan
>
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