Update trigger

/*EXAMPLE OF A UPDATE FUNCTION WITH TRIGGER PLPGSQL*/

CREATE OR REPLACE FUNCTION update_aumentarpreco ()
    RETURNS TRIGGER
    LANGUAGE PLPGSQL
    AS 
    $BODY$
BEGIN
	IF OLD.ps_availqty = 2 THEN
		RETURN NULL;
	END IF;
		
    IF NEW.ps_availqty = 2 THEN
        NEW.ps_supplycost = OLD.ps_supplycost * 0.10;
        RETURN NEW;
    END IF;
	
    RETURN NEW;
END;
    $BODY$ 

CREATE TRIGGER update_aumentarpreco
    BEFORE UPDATE OF ps_availqty ON partsupp
    FOR EACH ROW
    EXECUTE PROCEDURE update_aumentarpreco ();

/*DROP TRIGGER update_aumentarpreco ON partsupp*/
/*Testing

UPDATE
    partsupp
SET
    ps_availqty = 4
WHERE
    ps_suppkey = 2*/

Similar codes

12 votes169 views4 answers
Install mysql ubuntu 18.04
SQL
1 vote187 views1 answer
Tsql replace value in json
SQL
1 vote175 views1 answer
Sqlite create index
SQL
0 vote169 views1 answer
Java spring boot connect to sql server
SQL
0 vote192 views2 answers
Pl sql auto increment
SQL
1 vote133 views1 answer
Postgres division by zero
SQL
1 vote176 views1 answer
Oracle list data files
SQL
8 votes194 views2 answers
Mysql grant all privileges to user from any host
SQL
0 vote154 views1 answer
ORACLE SUBSTRING SYNTAX
SQL
0 vote172 views1 answer
Postgresql show owner of database
SQL