Make parent_id a unique key. Doing a select first and inserting if no
result will work 99.9% of the time; however, consider 2 rows being
inserted at the same time.
On Tuesday, March 23, 2010, Kyong Kim <kykimdba@stripped> wrote:
> I need to INSERT a row into a table only if it does not exist to
> insure that there won't be duplicate rows.
> Due to the the usage case and the design of the primary key,
> non-unique id + auto increment, I don't think insert ignore is an
> What would be simplest and cheapest way to make sure that given the
> following schema
> create table some_table
> ( parent_id int //non-unique
> seq_id int auto_increment ) ENGINE=INNODB
> that no row with the same parent_id can be inserted?
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