Cursors

A cursor is used to refer to an output row i.e. it is a pointer to a row in the results set.

We can update tuples fetched by the cursor by declaring that the cursor is for update:

DECLARE c CURSOR FOR SELECT * FROM instructor WHERE dept_name = ‘Music’ FOR UPDATE;

UPDATE instructor
SET salary = salary + 100
WHERE CURRENT OF c

The UPDATE command shown above will update the tuple at the current location of the cursor c.