Oracle9i OLAP Developer's Guide to the OLAP API Release 2 (9.2) Part Number A95297-01 |
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Understanding OLAP API Metadata, 10 of 11
MdmAttribute
is a subclass of MdmDimensionedObject
, which is an abstract subclass of MdmSource
.
An MdmAttribute
represents a particular characteristic of the elements of an MdmDimension
. An MdmAttribute
maps one element of the MdmDimension
to a particular value. A typical example is an MdmAttribute
that records the gender of each customer in an MdmDimension
called mdmCustomersDim
. In this case, the elements of the MdmAttribute
have the values "Female" and "Male".
The values of an MdmAttribute
might be String
values (such as "Female"), numeric values (such as 45), or objects (such as MdmLevel
objects).
Like an MdmMeasure
, an MdmAttribute
has elements that are organized by its MdmDimension
. For example, the gender MdmAttribute
has one element (with "Female" or "Male" as its value) for each element of the MdmDimension
called mdmCustomersDim
.
Typically, not all of the elements of an MdmDimension
have meaningful mappings to the values of a given MdmAttribute
. For example, the gender MdmAttribute
applies only to the lowest level of mdmCustomersDim
, because gender makes no sense for higher levels such as cities or states. If an MdmAttribute
does not apply to some elements of an MdmDimension
, then their MdmAttribute
values are null
.
Some MdmAttribute
objects provide a mapping that is one-to-many, rather than one-to-one. Therefore, a given element in an MdmDimension
might map to a whole set of MdmAttribute
elements. For example, the MdmAttribute
that serves as the ancestors attribute for an MdmHierarchy
maps each MdmHierarchy
element to its set of ancestor MdmHierarchy
elements.
A given MdmAttribute
is based on an attribute that was specified for a dimension or a level by a database administrator using the OLAP Metadata APIs.
The following table lists the elements for an MdmAttribute
called mdmCustomersDimGender
, which is based on the MdmDimension
called mdmCustomersDim
. Note that the values of the MdmAttribute
are null
for the city, country, and region levels. There are meaningful values only for the customer level, where each customer is represented by a number.
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