Recent RDBMS SQL Interview Questions and Answers

Recent RDBMS SQL Interview Questions and Answers

What is the advantage to use trigger in your PL?

Triggers are fired implicitly on the tables/views on which they are created. There are various advantages of using a trigger. Some of them are:

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Suppose we need to validate a DML statement(insert/Update/Delete) that modifies a table then we can write a trigger on the table that gets fired implicitly whenever DML statement is executed on that table.
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Another reason of using triggers can be for automatic updation of one or more tables whenever a DML/DDL statement is executed for the table on which the trigger is created.
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Triggers can be used to enforce constraints. For eg : Any insert/update/ Delete statements should not be allowed on a particular table after office hours. For enforcing this constraint Triggers should be used.
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Triggers can be used to publish information about database events to subscribers. Database event can be a system event like Database startup or shutdown or it can be a user even like User loggin in or user logoff.