Oracle PL/SQL Programming: A Developer's Workbook

Expert

Q:
12-17.	When you declare a cursor variable as the formal parameter of a subprogram that opens the cursor variable, you must specify the parameter to be of mode OUT or IN OUT. That way, the subprogram can pass an open cursor back to the caller.
Q:
12-18.	Problems are: You cannot pass a cursor variable through the parameter list of a remote procedure call (RPC). The variable points to a result set in the current database instance. You cannot use comparison operators to test two or more different cursor variables for equality, inequality, or nullity (IS NULL or IS NOT NULL). You cannot use a REF CURSOR type to specify the element type of a collection (error PLS-00990). As a consequence, a cursor variable may not be an element in a nested table, index-by table, or VARRAY. Even through the two different REF CURSOR types have the same RETURN clause, they are considered different types; you cannot, therefore, assign tmp_cv to emp_cv.
Q:
12-19.	The declaration in (a) defines a cursor variable in SQL*Plus of type REF CURSOR (weak). The following is an example of declaring and using such a variable: SQL> VARIABLE bysal REFCURSOR SQL> exec :bysal := empinfo.open (empinfo.bysal) PL/SQL procedure successfully completed. SQL>
Q:
12-20.	Here is one possible implementation: /* Filename on web page: cah.pkg */ CREATE OR REPLACE PACKAGE cah AS TYPE tainted_person IS REF CURSOR; PROCEDURE identify_person ( ...