Accessing OLAP using ASP.NET - Technical Terms in OLAP
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To make this document simple, I provide only the definitions for the commonly used technical terms in OLAP. For more information, refer to SQL Server 2000 Online documentation.
Data warehouse
A database specifically structured for query and analysis. A data warehouse typically contains data representing the business history of an organization.
Data mart
A subset of the contents of a data warehouse. A data mart tends to contain data focused at the department level, or on a specific business area.
fact table
A central table in a data warehouse schema that contains numerical measures and keys relating facts to dimension tables. Fact tables contain data that describes specific events within a business, such as bank transactions or product sales.
dimension
A structural attribute of a cube, which is an organized hierarchy of categories (levels) that describe data in the fact table. These categories typically describe a similar set of members upon which the user wants to base an analysis. For example, a geography dimension might include levels for Country, Region, State or Province, and City.
level
The name of a set of members in a dimension 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.
hierarchy
A logical tree structure that organizes the members of a dimension such that each member has one parent member and zero or more child members.
multidimensional structure
A database paradigm that treats data not as relational tables and columns, but as information cubes that contain dimension and summary data in cells. Each cell is addressed by a set of coordinates that specify a position in the structure's dimensions. For example, the cell at coordinates {SALES, 1997, WASHINGTON, SOFTWARE} would contain the summary of software sales in Washington in 1997.
cube
A set of data that is organized and summarized into a multidimensional structure defined by a set of dimensions and measures.
member
An item in a dimension representing one or more occurrences of data. A member can be either unique or nonunique. For example, 1997 and 1998 represent unique members in the year level of a time dimension, whereas January represents nonunique members in the month level because there can be more than one January in the time dimension if it contains data for more than one year.
measure
In a cube, a set of values that are based on a column in the cube's fact table and are usually numeric. Measures are the central values that are aggregated and analyzed.
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