Understanding Dimension Attributes

A dimension attribute is an OLAP metadata entity. This means that it is a logical object, identified by name and owner, within the OLAP Catalog.

Dimension attributes define sets of level attributes for a dimension. Dimension attributes may include level attributes for some or all of the dimension's levels. For time dimensions, the dimension attributes end date and time span must be defined for all levels. Dimension attributes are fully described in "OLAP Metadata Model".

Use the procedures in the CWM2_OLAP_DIMENSION_ATTRIBUTE package to create, drop, and lock dimension attributes and to specify descriptive information for display purposes.

Several dimension attribute names are reserved, because they have special significance within CWM2. The level attributes comprising a reserved dimension attribute will be mapped to columns containing specific information. The reserved dimension attributes are listed in Table 19-1.

Table 19-1  Reserved Dimension Attributes

Dimension Attribute	Description
Long Description	A long description of the dimension member.
Short Description	A short description of the dimension member.
End Date	For a time dimension, the last date in a time period. (Required)
Time Span	For a time dimension, the number of days in a time period. (Required)
Prior Period	For a time dimension, the time period before this time period.
Year Ago Period	For a time dimension, the period a year before this time period.
ET Key	For an embedded total dimension, the embedded total key, which identifies the dimension member at the lowest level in a row of the dimension table.
Parent ET Key	For an embedded total dimension, the dimension member that is the parent of the ET key.
Grouping ID	For an embedded total dimension, the grouping ID (GID), which identifies the hierarchical level for a row of the dimension table.
Parent Grouping ID	For an embedded total dimension, the dimension member that is the parent of the grouping ID.

The parent dimension must already exist before you can create dimension attributes for it. To fully define a dimension, follow the steps listed in "Constructing a Dimension".