SQL Server Cursor

Süleyman Kaş

6 years ago

Hello there,

A query operation is performed on SQL Server. If the cursor is on the line, the data in that line is processed.

DML (insert – update – delete) operations to be performed on large tables in databases with intense transaction are very risky.

Therefore, the cursor should be used in DML operations.

Example,

declare @ID varchar(20)
 
declare cursorSK cursor for
 
SELECT birthdate
  FROM users where birthdate='2050-01-01 00:00:00.000'
 
 
   OPEN cursorSK
 
       FETCH NEXT FROM cursorSK
 
       INTO @ID
 
          WHILE @@FETCH_STATUS = 0
 
          BEGIN
 
         --here we can do the process we want the records returned by the row line query.
 
         -- Exp:
 
             update users set birthdate=null where birthdate=@ID  --we are updating the birthdate variables from the above query result to null. 
 
       FETCH NEXT FROM cursorSK INTO @ID
 
     END
 
   CLOSE cursorSK
 
DEALLOCATE cursorSK

declare @ID varchar(20)

declare cursorSK cursor for

SELECT birthdate

FROM users where birthdate='2050-01-01 00:00:00.000'

OPEN cursorSK

FETCH NEXT FROM cursorSK

INTO @ID

WHILE @@FETCH_STATUS = 0

BEGIN

--here we can do the process we want the records returned by the row line query.

-- Exp:

update users set birthdate=null where birthdate=@ID --we are updating the birthdate variables from the above query result to null.

FETCH NEXT FROM cursorSK INTO @ID

END

CLOSE cursorSK

DEALLOCATE cursorSK