|Oracle8i SQL Reference
Release 2 (8.1.6)
Operators, 10 of 10
Like built-in operators, user-defined operators take a set of operands as input and return a result. However, you create them with the
CREATE OPERATOR statement, and they are identified by names (e.g.,
MERGE). They reside in the same namespace as tables, views, types, and stand-alone functions.
Once you have defined a new operator, you can use it in SQL statements like any other built-in operator. For example, you can use user-defined operators in the select list of a
SELECT statement, the condition of a
WHERE clause, or in
ORDER BY clauses and
GROUP BY clauses. However, you must have
EXECUTE privilege on the operator to do so, because it is a user-defined object.
For example, if you define an operator
CONTAINS, which takes as input a text document and a keyword and returns 1 if the document contains the specified keyword, you can then write the following SQL query:
"CREATE OPERATOR" and Oracle8i Data Cartridge Developer's Guide for more information on user-defined operators.