|Oracle9i OLAP Services Developer's Guide to the Oracle OLAP API
Release 1 (9.0.1)
Part Number A88756-01
Discovering the Available Metadata, 4 of 8
The metadata objects that are accessible through a given
MdmMetadataProvider are organized in a tree-like structure, with the root
MdmSchema at the top. Under the root
MdmDimension objects, and one or more
MdmSchema objects, which are referred to as subschemas.
Subschemas have their own
MdmDimension objects. Optionally, they can have their own subschemas as well.
MdmSchema contains all the
MdmDimension objects that are in the subschemas. Therefore, a given
MdmDimension always appears twice in the tree. It appears once under the root
MdmSchema and again under the subschema.
The starting point for discovering the available metadata objects is the root
MdmSchema, which is the top of the tree. The following diagram illustrates an example in which one subschema has two
MdmMeasure objects and two
MdmDimension objects. Another subschema has one
MdmMeasure object and two
MdmDimension objects. The root
MdmSchema contains, in addition to the two subschemas, all three
MdmMeasure objects and all four
Using the OLAP management feature of Oracle Enterprise Manager, a database administrator arranges dimensions and measures under one or more top-level measure folders. When OLAP Services maps the measure folders to
MdmSchema objects, it always creates the root
MdmSchema above the
MdmSchema objects for the top-level measure folders. Therefore, even if the database administrator creates only one measure folder, its corresponding
MdmSchema will be a subschema under the root.
For more information about MDM metadata objects and how they map to OLAP objects in the OLAP management feature of Oracle Enterprise Manager, see Chapter 2.
The following code gets the root
MdmSchema for an
MdmMetadataProvider called mp.