Important Formula

What Is Trigger In Dbms. A trigger uses the special table to keep a copy of the row which we have just inserted, deleted or modified. Each trigger is attached to a single, specified table in the database.

A trigger is a procedure of sql statements, which is automatically fired when the dml statements are executed on the table of the database. Triggers can only be nested inside a table. Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion.

What Is Index In Dbms. An index helps to speed up select queries and where clauses, but it slows down data input, with the update and the insert. What is indexing in dbms?

This technique is used for huge databases, when column is of low cardinality and these columns are most frequently used in the query. The index is a type of data structure. In a dense index, a record is created.