Well cursors help us to do an operation on a set of data
that we retreive by commands such as Select columns from
table. For example : If we have duplicate records in a table
we can remove it by declaring a cursor which would check the
records during retreival one by one and remove rows which
have duplicate values.

Cursors is one of the data object which is used to access 
and manipulate the datas in the result set.

broadly speaking ,,cursor can perfomr operaions on database 
much like functions except returning a value i think

Cursors are logical areas created on physical areas, i.e., 
tables to find a particular nth record.

Basically cursor in an active dataset depends on query.
it is good to handling set of data.

Cursors are the private memory area in the SGA. they store 
the result set of a query. And they are used to fetch 
multiple rows from the tables in the pl/sql block

if we ant to retrive data from a database table having 
duplicate entries which violates primarykey rule
we can handle this case using cursor, it by declaring a 
cursor which would check the
records during retreival one by one and remove rows which
have duplicate values. there are many types of cursors to  
fetch data in diffrent order like fetch first,fetch 
last ,fetct prior,fetch next,fetch abslute n,fetch relative 
n

Cursors allow you to take a set of data and process record 
by record