An apparatus, program product and method represent a database query access plan
a query execution data structure including a plurality of query node objects arranged
into a tree relationship to define a parent node object and at least one child
node object, and an attribute data structure that references a plurality of attributes
utilized by the query execution data structure. At least one of the parent and
child node objects includes an attribute operation data structure configured to
manipulate at least a subset of the plurality of attributes in the attribute data
structure by accessing the attribute operation data structure. By partitioning
the functionality of a query access plan into a collection of node objects and
an attribute data structure, and then providing within at least a subset of the
node objects attribute operation data structures that manipulate the attribute
data structure, the resulting query engine architecture becomes significantly extendible
and adaptable. Moreover, through appropriate selection of attribute operations,
and coding of such operations using directly executable program code, optimal query
engine performance may also be obtained.
