Updating specific row in cursor
The SQL:2003 standard defines positioned update and positioned delete SQL statements for that purpose.Such statements do not use a regular WHERE clause with predicates. The cursor must be opened and already positioned on a row by means of The cursor must operate on an updatable result set in order to successfully execute a positioned update or delete statement.Programmers may declare cursors as scrollable or not scrollable.The scrollability indicates the direction in which a cursor can move.
In this scenario, a cursor enables the sequential processing of rows in a result set.
Otherwise, the DBMS would not know how to apply the data changes to the underlying tables referred to in the cursor.
Using cursors in distributed transactions (X/Open XA Environments), which are controlled using a transaction monitor, is no different from cursors in non-distributed transactions.
A cursor can be SENSITIVE or INSENSITIVE to such data modifications.
A sensitive cursor picks up data modifications affecting the result set of the cursor, and an insensitive cursor does not.