Dimensional Warehouse Model elements

These topics list the Dimensional Warehouse Model elements.

Package
A package is a grouping of Dimensional Warehouse Model (DWM) elements for organizational purposes. Packages partition elements by grouping them according to the type of artifacts they hold and their business opportunities.
Dimension entity
A dimension entity provides descriptive, nonnumeric information about the numerical values in a fact entity. Dimension entities originate from the business terms that are defined as dimensions in the analytical requirements and from the fundamental entities in the Atomic Warehouse Model (AWM). A dimension entity is composed of elements of a fundamental entity, and all other elements from other fundamental entities that together form an aggregation path.
Bridge entity
A bridge entity is used to capture a many-to-many relationship that cannot be accommodated by the natural granularity of a single fact or dimension entity. A bridge entity serves to bridge between the fact and dimension entities to support many-valued dimension attributes. A bridge entity is also useful to support relationships between dimension entities, if business users want to be able to analyze those relationships without traversing fact entities. In this context, the cardinality of the relationship does not matter and even one-to-many relationships between dimension entities may be supported by a bridge entity. Bridge entities are sometimes historically referred to as associative entities.
Array entity
An array entity resolves a multivalued relationship which emanates from either a dimension or a fact.
Fact entity
Fact entities group measures (facts) that share dimensions at the same level of granularity. The fact entity is the core entity of a dimensional data structure. All or a subset of the measures and dimensions that are held in a fact entity may be used by one or more downstream data marts. The measures in the fact entities support the measures defined in the analytical requirements.
Relationship
A relationship links a fact entity (child) with its dimension entities (parents), a bridge entity to its parent dimension entities, or an outrigger entity to its dimension entity.
Attribute
A Dimensional Warehouse Model (DWM) attribute represents a single information concept that describes a dimension entity, bridge entity, hierarchy bridge entity, outrigger entity or fact entity.
Attribute group
Attribute groups provide a single definition point for widely used groups of technical attributes, such as validity timestamps, instead of creating them on an ad-hoc basis.
Data domain
A data domain defines the type of data value that is held by an attribute in a data model. UDMH is delivered with predefined data domains.
Diagram
A diagram is a graphical representation of Dimensional Warehouse Model (DWM) elements and their relationships that shows in a graphical form how model elements are related to each other. A diagram can also be used to represent the DWM elements that belong to a project scope. In ERwin, the diagram construct is supported by a subject area.

Parent topic: Dimensional Warehouse Model