1.

What is Cursor? How to use a Cursor?

Answer»

A DATABASE CURSOR is a control structure that allows for the traversal of records in a database. Cursors, in addition, facilitates processing after traversal, such as retrieval, addition, and deletion of database records. They can be viewed as a pointer to ONE row in a set of rows.

Working with SQL Cursor:

  1. DECLARE a cursor after any variable declaration. The cursor declaration must always be associated with a SELECT Statement.
  2. Open cursor to initialize the RESULT set. The OPEN statement must be called before fetching rows from the result set.
  3. FETCH statement to retrieve and move to the next row in the result set.
  4. Call the CLOSE statement to deactivate the cursor.
  5. Finally use the DEALLOCATE statement to delete the cursor definition and release the associated resources.
DECLARE @name VARCHAR(50) /* Declare All Required Variables */DECLARE db_cursor CURSOR FOR /* Declare Cursor Name*/SELECT nameFROM myDB.studentsWHERE parent_name IN ('Sara', 'Ansh')OPEN db_cursor /* Open cursor and Fetch data into @name */ FETCH nextFROM db_cursorINTO @nameCLOSE db_cursor /* Close the cursor and deallocate the resources */DEALLOCATE db_cursor


Discussion

No Comment Found

Related InterviewSolutions