sal_diff); END; / keyword if you want the trigger to query or change the same table, because triggers can only do that after the initial changes are applied and the table is back in a consistent state.
We can create a trigger to update the 'product_price_history' table when the price of the product is updated in the 'product' table.
1) Create the 'product' table and 'product_price_history' table Once the above update query is executed, the trigger fires and updates the 'product_price_history' table.
Because the trigger uses the clause, it might be executed multiple times, such as when updating or deleting multiple rows.
2) Statement level trigger - An event is triggered for each sql statement executed.
While a trigger is , which determines whether the trigger fires before or after the triggering statement runs and whether it fires for each row that the triggering statement affects. If the trigger is created on a schema or the database, then the triggering event is composed of either DDL or database operation statements, and the trigger is called a )".
By default, a trigger is created in the enabled state. When a trigger fires, tables that the trigger references might be undergoing changes made by SQL statements in other users' transactions.
UPDATE bank_transactions SET txn_number = 'NEWTXN8080' WHERE txn_id = 1; UPDATE bank_transactions SET txn_number = 'NEWTXN9595' WHERE txn_id = 2; -- output 1 rows updated. Dhaval Dadhaniya is a software engineer by profession and reader/writter by passion.
CREATED_DATE); END; --Inserting values INSERT INTO BANK_TRANSACTIONS values ('1','TXN1234','Peter Thomas','12-MAY-2017','HR',sysdate); INSERT INTO BANK_TRANSACTIONS values ('2','TXN9999','Jemes Patel','10-JUN-2016','HR',sysdate); select * from BANK_TRANSACTIONS; --updating values.