A database operation mechanism includes the capability of specifying a
predefined database operation as a source of data for a different
database operation. When the different database operation needs to be
performed, the database operation mechanism determines whether the
different database operation can use a predefined database operation as a
data source. If so, the predefined database operation is specified as the
source of data for the different database operation. If the different
database operation cannot use a predefined database operation as a data
source, the database operation mechanism determines whether the different
database operation can use a modified form of a predefined database
operation as a data source. If so, the different database operation may
use the modified predefined database operation as a source of data. If
the different database operation cannot use a predefined database
operation or a modified form of a predefined database operation as a data
source, a different database operation is generated and executed.