How to create a trigger in postgresql-CodePudding

I need to create a trigger in postgres where, when I add a record to table A, it automatically inserts its primary key value (which is auto incremented) into table B, the primary key of table A is the foreign key in table B.

I have tried doing it through pgadmin but it does not allow me to save. Could someone help out please.

CodePudding user response：

First create the following trigger function.

CREATE OR REPLACE FUNCTION auto_insert() RETURNS TRIGGER AS
$BODY$
BEGIN
    INSERT INTO
        B(a_id)
        VALUES(new.id);

           RETURN new;
END;
$BODY$
language plpgsql;

And then attach the trigger function to table A.

CREATE TRIGGER auto_inserter
 AFTER INSERT ON A
 FOR EACH ROW
 EXECUTE PROCEDURE auto_insert();