Olap Terminology

The server component of Microsoft Analysis Services that is specifically designed to create and maintain multidimensional data structures and provide multidimensional data in response to client queries.

Databases serve as containers for related data sources, cubes, dimensions, data mining models, and the objects they share.

Cubes are the main objects in Olap, a technology that provides fast access to data in a data warehouse.

A cube consists of measures based on one or more fact tables and dimensions based on one or more dimension tables.

A key performance indicator is a collection of calculations that are associated with a measure group in a cube that are used to evaluate business success. Typically, these calculations are a combination of Multidimensional Expressions (MDX) expressions or calculated members. KPIs also have additional meta data that provides information about how client applications should display the results of the KPI's calculations.

A dimension is based on a table or view in a data source view. Dimensions exist independent of a cube, can be used in multiple cubes, and can be used multiple times in a single cube

A hierarchy is created for every attribute of a dimension. You can group attributes together in a logical tree structure.

•	Attribute hierarchy An attribute hierarchy is a based on a single attribute in a dimension. Attribute hierarchy are represented by

•	User hierarchy Attributes can be, and typically are, arranged into user-defined, multilevel hierarchies that provide the drill-down paths by which users can browse the data in the measure groups to which the attribute is related. User hierarchy are represented by

Display folder are used to group objects of the same type that logically belong to the same group. For example, "Gender" and "Age" attribute hierarchies could be grouped together in a "Demographic" display folder. Several object types support grouping in display folders, including hierarchies and , KPIs.

A measure generally represents a column that contains quantifiable, aggregatable (usually numeric) data mapped to a column in a fact table.

In a cube, measures are grouped by their underlying fact tables into measure groups. Measure groups are used to associate hierarchies with measures.

The table that contains the measure groups and references on the deepest level of the cube.

An item in a hierarchy representing one or more occurrences of data. A member can be either unique or non unique. For example, 1997 and 1998 represent unique members in the year level of a time hierarchy, whereas January represents non unique members in the month level because there can be more than one January in the time hierarchy if it contains data for more than one year.

The name of a set of members in a hierarchy such that all members of the set are at the same distance from the root of the hierarchy. For example, a time hierarchy may contain the levels Year, Month, and Day.