Answers for "trigger definition in sql"

sql trigger example

-- SQL Server (update my_table after update on my_table)
CREATE TRIGGER trigger_name ON my_table AFTER UPDATE AS
IF UPDATE (col_name)	-- Optional, for particular column
BEGIN
    UPDATE my_table SET my_col_date = getdate() FROM my_table 
END;
-- Oracle (insert into log table after update on my_table)
CREATE OR REPLACE TRIGGER trigger_name AFTER UPDATE ON my_table
FOR EACH ROW
BEGIN
    INSERT INTO my_log_table (LOG_DATE, ACTION) VALUES (SYSDATE, 'Changed');
END;

how use trigger in sql

CREATE TRIGGER Product_Details_tr 
BEFORE INSERT ON Product_Details 
FOR EACH ROW 
SET NEW.User_ID = CURRENT_USER();

what is a trigger in sql

-- Azure SQL Database Syntax   
-- Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger)  
  
CREATE [ OR ALTER ] TRIGGER [ schema_name . ]trigger_name   
ON { table | view }   
 [ WITH <dml_trigger_option> [ ,...n ] ]   
{ FOR | AFTER | INSTEAD OF }   
{ [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] }   
  AS { sql_statement  [ ; ] [ ,...n ] [ ; ] > }  
  
<dml_trigger_option> ::=   
        [ EXECUTE AS Clause ]