You must declare a cursor before you can use it. The declaration specifies the query that defines the cursor result set. You can explicitly define a cursor as updatable or read-only by using the for update or for read only keywords. If you omit either one, Adaptive Server determines whether the cursor is updatable based on the type of query that defines the cursor result set. However, Sybase suggests that you explicitly specify one or the other; for updates, this ensures that Adaptive Server performs the positioned updates correctly. You cannot use the update or delete statements on the result set of a read-only cursor.
