December 2002
Intermediate to advanced
928 pages
85h 29m
English
New with Oracle9i, a cursor expression is a cursor that is used as a column expression in the select list of an explicit cursor.
Cursor expressions can reduce the amount of redundant data returned to a calling program; for this reason, you may wish to use it in place of techniques that involve joining the tables together. The cursor expression is automatically opened when the parent row is fetched. Cursor expressions can be nested as well. These nested cursors are closed when one of the following occurs:
The nested cursor is explicitly closed by the program.
The parent cursor is closed.
The parent cursor is re-executed.
An exception is raised during the fetch of the parent row.