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1. Trigger to check a foreign key without using foreign key

Hello,

I want to use a trigger to check a foreign key.

Let's assume :

table LIGNES_V contains field ID_ARTICLE char(25)
table STOCK contains field S_ID char(10)

In table LIGNES_V, ID_ARTICLE must contain '' or a valid value from S_ID in
STOCK
(because of the '' -> could not use a standard foreign key)

In the update trigger of LIGNES_V, i placed

if update(id_article) and exists (select id_article from inserted where
(id_article>' ') and  (left(id_article,10) not in (select s_id from stock)))
 RAISERROR ( 'ID_ARTICLE does not match S_ID !',16,1 )

it works very fine and gives the correct result.

BUT : i assume that this request containing a sub-request will result in bad
performances.

Does somebody have an idea to write this trigger on a more-performing way ?

Thanks for help,

Kind regards,

Guy

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