Which of the following is the correct syntax to create a trigger function in PostgreSQL for data validation?

easy📝 Syntax Q3 of 15

PostgreSQL - Triggers in PostgreSQL

ACREATE FUNCTION validate_data() RETURNS trigger AS $$ BEGIN RETURN OLD; END; $$ LANGUAGE plpgsql;

BCREATE TRIGGER validate_data() RETURNS trigger AS $$ BEGIN RETURN NEW; END; $$ LANGUAGE plpgsql;

CCREATE FUNCTION validate_data() RETURNS void AS $$ BEGIN RETURN NEW; END; $$ LANGUAGE sql;

DCREATE FUNCTION validate_data() RETURNS trigger AS $$ BEGIN RETURN NEW; END; $$ LANGUAGE plpgsql;

Step-by-Step Solution

Solution:

Step 1: Identify correct function creation syntax
Trigger functions must return type 'trigger' and use plpgsql language.
Step 2: Check return statement for validation
Returning NEW allows the insert/update to proceed with validated data.
Final Answer:
CREATE FUNCTION validate_data() RETURNS trigger AS $$ BEGIN RETURN NEW; END; $$ LANGUAGE plpgsql; -> Option D
Quick Check:
Trigger function syntax = CREATE FUNCTION validate_data() RETURNS trigger AS $$ BEGIN RETURN NEW; END; $$ LANGUAGE plpgsql; [OK]

Quick Trick: Trigger functions must return 'trigger' type and NEW row [OK]

Common Mistakes:

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