Standard Form Dimensions - OLAP

The dimensions of a cube are typically hierarchical in nature and thus have levels and hierarchies. Dimensions in an analytic workspace are frequently called embedded total dimensions because they contain members at all levels, and thus are used to define measures with aggregate data. Dimension members are acquired from multiple level columns of a relational dimension table.
An embedded total dimension has, in addition to the dimension object, at least one level and one hierarchy. A flat dimension does not require them. All dimensions have a default order attribute, as described in "Standard Form Attributes". Time attributes must have end date and time span attributes.

Dimdef Dimension

A dimdef dimension (that is, a dimension used in a cube) in an analytic workspace has the name defined in the metadata, such as TIME or PRODUCT, and may have a prefix specified in the build. The dimension has a TEXT data type unless you redefine it before loading the dimension members. Dimension members may have a level prefix added to the source values.

Contents of an Analytic Workspace Dimension

The analytic workspace dimension members may be exactly the same as those in the relational dimension table, or they may have a level prefix. The prefix is an option in the build. Example shows how the Global PRODUCT dimension members would appear if a prefix were specified in the build. (The Global star schema provides surrogate keys, so no prefix is actually needed to assure unique dimension members across levels.)

All dimension members are sorted during the load process. For the Time dimension, the members are sorted by level and by end-date within the levels. This order is required to support time-series analysis, which is based on the relative position of time periods within the dimension. Other dimensions are sorted by level and alphanumerically by dimension member within the levels. A default order attribute identifies the original order in which the dimension members were loaded into the analytic workspace.

Global Products with Level Prefixes

Properties of an Analytic Workspace Dimdef Dimension

Dimdef Dimension Properties

Properties of an Analytic Workspace Dimdef Dimension  Dimdef Dimension Properties

Standard Form Metadata for Dimensions

Standard form metadata for dimensions is stored in these objects:

  • ALL_DIMENSIONS dimension
  • ALL_DESCRIPTIONS variable
  • AW_NAMES variable
  • DIM_LEVELS valueset

ALL_DIMENSIONS Dimension

The ALL_DIMENSIONS dimension contains the names of all dimensions in this format:

workspace.dimension.DIMENSION

For example: GLOBAL_AW.PRODUCT.DIMENSION

ALL_DIMENSIONS is a base dimension of the ALL_OBJECTS concat dimension.

ALL_OBJECTS dimensions ALL_DESCRIPTIONS and AW_NAMES, so these catalogs have an entry for each measure.

ALL_DESCRIPTIONS Variable for Dimensions

The ALL_DESCRIPTIONS variable contains short, long, and plural names for the dimensions. All objects have a short name acquired from the metadata, but may or may not have long and plural names.

AW_NAMES Variable for Dimensions

The AW_NAMES measure provides the fully qualified name of the workspace dimension object in this format:

schema.workspace!dimension

For example: GLOBAL_AW.GLOBAL!PRODUCT

DIM_LEVELS Valueset

The DIM_LEVELS valueset identifies the levels defined for each dimension.


All rights reserved © 2018 Wisdom IT Services India Pvt. Ltd DMCA.com Protection Status

OLAP Topics