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i want to create procedure with BL in its body. i find the same example in SQL but not in postgresql.
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A trigger is a special type of stored procedure that automatically runs when an event occurs in the database server. DML triggers run when a user tries to modify data through a data manipulation language (DML) event.
Syntax. CREATE TRIGGER trigger_name [BEFORE|AFTER|INSTEAD OF] event_name ON table_name [ -- Trigger logic goes here.... ]; Here, event_name could be INSERT, DELETE, UPDATE, and TRUNCATE database operation on the mentioned table table_name. You can optionally specify FOR EACH ROW after table name.
INSTEAD OF triggers do not support WHEN conditions. Typically, row-level BEFORE triggers are used for checking or modifying the data that will be inserted or updated. For example, a BEFORE trigger might be used to insert the current time into a timestamp column, or to check that two elements of the row are consistent.
The trigger will fire once per statement, so if your INSERT that causes this trigger to fire inserts 25 rows, you'll get the trigger fired once and the Inserted pseudo table will contain 25 rows.
Every RDBMS have their own SQL language. You can't create trigger in PostgreSQL as you can create in Oracle/MS SQL etc. In order to create trigger in PostgreSQL you have to
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