They are used to display information of a table into 
effective number and also display more than one record at a
time.

A cursor is a handle or name for sql area
two types of cursors they are
Explicit cursor: Created by user
Implicit Cursor: created by oracle automatically when ever 
DML is performed.

As this would be not specific DW Concept but rather more on 
RDBMS Programming concept.

Cursor is nothing but the pointer of memory addres to your 
query result.

Explicit Cursor : User need to specifically declared in 
your program (procedure/function)

Implicit Cursor : Any DML; it will handled by RDBMS.

1.A PRIVATE MEMORY/BUFFER.
2.IT IS USED TO HOLD THE DATA FROM TABLES OR VIEWS IN 
MEMORY LOCATION FOR MANIPULATION PURPOSE.
3.VALID IN PL/SQL BLOCK ONLY.
4.ARE VARIABLE THAT YOU CAN DEFINE IN THE DECLARE SECTION 
OF THE PL/SQL BLOCK.
ORACLE USES WORK AREA CALLED PRIVATE SQL AREAS TO EXECUTE 
SQL STATEMENT AND STORE INFORMATION.
5.IT IS A VIRTUAL TABLE TO PROCESS MULTIPLE RECORDS IN 
PL/SQL CONSTRUCT.