REF cursors are different than your typical, standard cursors. With standard cursors, you know the cursor's query ahead of time. With REF cursors, you do not have to know the query ahead of time. REF cursors let you create a cursor to be used in your PL/SQL block, for instance, and use that cursor, without knowing ahead of time what your particular query might be. This is often used when the cursor's query will be given to a stored procedure or function at runtime. For instance, you might want a function to compute the average of a column on a particular table. But you don't know ahead of time what the table or column will be. With regular cursors, you would need to know. But with REF cursors, you can pass the table and column to the function, and have the REF cursor build the cursor "on the fly".
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This was first published in December 2002