1)What is ref cursor? Where u can use this ref cursor?
2)What is difference between procedure and function?
3)What is trigger? How many types of triggers are there?
4)What is cursor? Explain different types of Cursors with example?
For difference between procedure and function please go through the following link http://www.roseindia.net/answers/viewqa/SQL/13605-What-is-difference-between-a-PROCEDURE-&-FUNCTION-.html
Trigger in database is a procedural code which is written for executing automatically on the response of certain events occurred on the particular table or view in database.
There are two types of trigger :
Row level trigger : These type of tiggers are executed for each row on update, insert, or delete.
Statement level trigger : These type of triggers are executed for each sql statement executed.
Cursor in database is a control structure which allows for traversing acrros records of database. Using cursor complex logic can be performed on row by row basis.
There are two types of cursor :
implicit cursor : These cursors are created implicitly i.e. when the DML statements such as insert, update, delete is executed.
explicit cursor : These cursors are created when the select statement is executed and it returns more than one row however, the action can be performed on one row at a time.