The Cursor is a handle (name or a pointer) for the memory associated with a specific statement. A cursor is basically an Area alocated by Oracle for executing the Sql Statements. Oracle Uses an Implicit Cursor statement for a single row query and Explicit Cursor for a multi row query.

Types of Cursor :

I) Implicit

II) Explicit (Explicit cursor has three sub-types)

1) Simple Cursor

2) Parameterised Cursor

3) Ref Cursor

There are different types of cursors but broadly classified into two :

Implicit cursor
Explicit cursor.

Every query that we issue on a database is an implicit cursor for eg. a select an update a delete etc.

On the otherhand explicit cursor is a user defined cursor eg: cursor explicit_cur as ...... ;

Implicit and Explicit.

Whenever you issue a SQL statement the Oracle server opens an area of memory in which the command is parsed and executed. This area is called a cursor.
When the executable part of a block issues a SQL statement PL/SQL creates an implicit cursor which PL/SQL manages automatically. The programmer explicitly declares and names an explicit cursor.

1) Open


2) Close

3) Fetch

and do some manipulations on the values

Explicit Cursors are classified into

1) Normal cursor

2) Parameterized cursor

3) Cursor For Loops and

4) REF cursors

REF Cursors:

Normally when we create a normal cursor we cant change the select query associated to that query (the query which is given at the time of definition)

But using REF cursors we can change the cursor statement also.

These REF cursors are useful when we are sending data from one environment to another environment.

Thanks And Regards

Nagaraja.Musturi