CODEWITHSUNDEEP
postgresqlplpgsql
AKSHAYEDAKOCHI
AKSHAYEDAKOCHI

Reputation: 1

Unable insert data to table beacuse of Trigger in Postgres

I created a table ebill(name varchar, prev int, curr int). There is a trigger that raises an exception when values with prevreading = currreading are entered. But it does not take other data also.

-- This is my function
CREATE OR REPLACE FUNCTION BILL_CHECK() RETURNS TRIGGER AS $$ 
BEGIN
 IF (NEW.PREVREADING=NEW.CURRREADING) THEN
   RAISE EXCEPTION 'Data Entry Error';
 END IF;
RETURN NULL;
END;
$$ LANGUAGE PLPGSQL;

--This is my trigger
CREATE TRIGGER BILL                                          
BEFORE INSERT OR UPDATE ON EBILL
FOR EACH ROW EXECUTE PROCEDURE BILL_CHECK();

INSERT INTO EBILL VALUES('MELVY',7,7);-- Raises Exception. Working.

NSERT INTO EBILL VALUES('MELVY',7,8);-- No change in the table.insert 00
INSERT 0 0

Why can't I insert the second group pf data?

Upvotes: 0

Views: 20

Answers (1)

Laurenz Albe
Laurenz Albe

Reputation: 246133

The problem is that you return NULL.

This is a signal to abort the data modification.

You should

RETURN NEW;

Upvotes: 1

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