Create explicit cursor

STEPS FOR CREATING AN EXPLICIT CURSOR:


To create an explicit cursor we need to follow 4 steps-
1) Declare
2) Open
3) Fetch
4) Close


In case of implicit cursor Oracle performs all these steps automatically for us.
Now we will take deep look on all these steps one by one-


1) DECLARE CURSOR- Declaring a cursor means initializing a cursor into memory.
We define explicit cursor in declaration section of our PL/SQL block and associate it at the SELECT statement.


SYNTAX OF DECLARE:


CURSOR cursor_name IS select_statement;


Syntax of declaration started with CURSOR keyword, followed by the cursor_name, cursor_name can be any thing which we want, we have another keyword IS which is followed by a select_statement.
After declaration we have to open the cursor.


2) OPEN CURSOR:
a) In order to put the cursor at work we have to open it first.
b) When we open the cursor the memory will be allotted to it., and it set put to the next step which is fetching the data from it.


SYNTAX OF OPEN CURSOR:


OPEN cursor_name;
This statement is generally written in execution section of the PL/SQL block.


3) FETCH CURSOR:
The process of retrieving the data from the cursor is known as fetching the cursor.
Once the cursor is declared and open we can fetch the data from it.


SYNTAX OF FETCH:


FETCH cursor_name INTO PL/SQL variable;
Or
FETCH cursor_name INTO PL/SQL record;


4) CLOSE CURSOR:
Once we have done working with cursor, it is advisable to close it as soon as the server comes across the closing statement of a cursor it will releases all the resources associated with it.


SYNTAX OF CLOSE:
CLOSE cursor_name;


Basic Programming Structure of Cursor:


DECLARE
CURSOR cursor_name IS select_statement;
BEGIN
OPEN cursor_name;
FETCH cursor_name INTO PL/SQL variable;
CLOSE cursor_name;


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