PLAN function [Miscellaneous]

Returns the long plan optimization strategy of a SQL statement, as a string.

Syntax 
PLAN( string-expression, [ cursor-type ], [ update-status ]  )
Parameters

  • string-expression   The SQL statement, which is commonly a SELECT statement but which may also be an UPDATE or DELETE statement.

  • cursor-type   A string. cursor-type can be asensitive (default), insensitive, sensitive, or keyset-driven.

  • update-status   A string parameter accepting one of the following values indicating how the optimizer should treat the given cursor:

Value Description
READ-ONLY The cursor is read-only.
READ-WRITE (default) The cursor can be read or written to.
FOR UPDATE The cursor can be read or written to. This is exactly the same as READ-WRITE.
See also
Standards and compatibility

  • SQL/2003   Vendor extension.

Example

The following statement passes a SELECT statement as a string parameter and returns the plan for executing the query.

SELECT PLAN(
   'SELECT * FROM Departments WHERE DepartmentID > 100' );

This information can help with decisions about indexes to add or how to structure your database for better performance.

The following statement returns a string containing the text plan for an INSENSITIVE cursor over the query SELECT * FROM Departments WHERE DepartmentID > 100;. 

SELECT PLAN(
   'SELECT * FROM Departments WHERE DepartmentID > 100',
   'insensitive',
   'read-only' );
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