hi,

Is there anyway of checking the database before adding a record.
I have a table where the primary key is self generated. Each time i want to add a record, i need to make sure that only one 'buyer id' (a field in the table) is allowed to be inserted. Duplicate 'buyer id' values are not allowed.
Can hibernate do that or do i just need to do a read before the insertion ?

Thanks.
tony

Hibernate version: 3.1

Put 'unique="true"' on the buyer_id mapping. You should do a find-by-buyer-id first though, as that's the row you'll be updating if the id isn't unique.

Hi.
Just by adding unique="true", doesnt make the buyer_id column unique.
A unique constraint has to be added to the column. When a duplicate value is added the database will throw an exception

hi,

thanks for the info. i am confused. mind explaining a little more ?

regards
tony

What I was trying to say is adding unique="true" in your mapping files for one-one relationships would not really help you. You can add duplicate values inspite of unique="true". What you really have to take care is add a unique constraint on the column and make unique="true" in your mapping files.

You can catch the unique constraint exception which implies that the value is already present.

With this you can actually avoid writing a select before an insert statement.

Hope this helps

Regards,
Fal