SSAS Dimension Usages - Relationship Types

Dimensions and Measure Groups can be related in different ways
  • Regular - A Direct relationship. Key column for the dimension is joined directly to the fact table
  • Fact - A Column in the fact table can be treated as a degenerate dimensions (usually used for drillthrough). Useful dimensional data is sometimes stored in a fact table to reduce duplication.
  • Referenced - A Dimension joined through another dimension is treated as if directly joined to the fact table. Key column for the dimension is joined indirectly to the fact table through a key in another dimension table
  • Many-to-Many - Handles many-to-many fact relationships. It is frequently useful to join a single fact to multiple dimension members.

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