Oracle DBA Interview Questions and Answers for Experienced - 1

Question: 1

What is a database trigger?

A database trigger is event driven program. You do not need to invoke a trigger.

It is fired whenever triggering event happens.

Question: 2

What is statement level trigger?

Statement level trigger is a trigger that excludes once for a statement regardless of the number of rows affected by the triggering event.

It is fired when a bulk insert (FORALL insert) is performed.

Question: 3

What is system level trigger?

These triggers are defined on system level. The triggers are fired at system level events, such as logon, logoff, startup and DDL which are explained as follows

Database startup triggers – Refer to the triggers that are fired at database startup. These can be used to automate certain action that you want to perform every time at startup.

Logon triggers - Refer to the triggers that are fired at logon. You can use these trigger to generate audit information related to logon.

Logoff triggers – Refer to the triggers that are fired at logoff time. You can include certain session closure related activities in these triggers.

DDL triggers – Refer to the triggers that are fired at DDL operations can be used to audit DDL changes.

Server error triggers – Refers to the triggers that are fired at server error. These triggers can be used to log error details and send email notification.

Question: 4

What is row level trigger?

A row trigger is fixed each time the table is affected by the triggering statement.

It is useful in case the code in the trigger depends on data provided by the triggering statement or rows that are affected.

Question: 5

What do you understand by Data Definition Language (DDL) trigger?

The DDL trigger executes every time a DDL statement is executed.

These are associated with a database or schema.