There are two types of triggers: 1. Row-level triggers 2. Statement-level triggers A row-level trigger executes each time a row is affected by a DML statement such as INSERT, UPDATE, and DELETE. If the statement affects 10 rows, the row-level trigger will execute 10 times. If the statement does not affect any row, the row-level trigger will not exe...

You typically use the triggers in the following scenarios: 1. Loggings. Some tables have sensitive data such as customer email, employee, and salary. You want to log all the changes. In this case, you can create the UPDATEtrigger to record the changes in a separate table. 2. Enforce complex integrity of data. You may create triggers that validate d...

We’ll use the employees table in the sample databasefor the demonstration. Suppose you want to log the changes of values in the salary column of the employees table. To do that, you create a separate tablefor storing the changes and use a trigger to insert the changes into this table. First, create the salary_changestable to store the salary change...