Create a Mart Dimension

A Model Object of type Mart Dimension can be created in the Datamart Layer.

What is a Mart Dimension

A Mart Dimension can use historized or non-historized sources from any persistent layer in any combination.

Historized Mart Dimensions can be loaded only from historized sources - the Datamart layer does not create history but only reads and transforms history from historized sources.

This means: there has to be at least one historized source to create an SCD2 historized dimension.

A Mart Dimension can contain any combination of SCD1 and SCD2 (and SCD0) attributes - but all SCD2 attributes should be loaded from historized sources.

When creating a Mart Dimension, the user does not need to join the historized source tables so, that the combined history is reflected correctly.

The user can join the historized source tables as if they were non-historized.

The generated code will take care of the correct history.

Creation steps

There are two possibilities to create a Mart Dimension Model Object:

• Create a Model Object with the Wizard:
  • Recommended possibility
  • Use the Wizard Create a Mart Dimension from a Raw Vault or a Business Vault or a Mart Composite that contains the following steps:
    • Create Model Object
    • Create Dataflow
    • Map selected Business Keys
    • Map selected Terms: exclude the Business Key(s) = {true}, exclude the Foreign Key(s) = {true}
    • Add to View
• Create a Model Object manually:
  
  • Create a Model Object of type Mart Dimension in the Gold Layer
  • Create a Dataflow Set 
  • Add a Model Object to the Dataflow Set: add the needed Model Object(s)
  • Auto-map the Source Terms: select the auto-map mode and auto-map all the needed Source Terms from the Source Model Object

• For each creation possibility, please:
  • Define the Property ValidFromSourceTerm for each historized Dataflow Model Object

• • Define the Property Historization Type on each Target Term that is not a Default Term
    • If the Source Term is not historized, set all the Target Terms as SCD1 (or SCD0)
    • If the Source Term is historized, set the concerned Target Term as SCD2

Properties

A Mart Dimension Model Object can be configured through the following Properties:

• Implementation Type

Default Terms

A Mart Dimension Model Object will include the following Default Terms:

• BG_SourceSystem
• BG_ValidFromTimestamp

Business Rules

The following Business Rules are checked during the Model Object creation:

• Dataflows amount: min = {1}, max = {1}
• Dataflow Sets amount: min = {1}, max = {1}
• Dataflow Set Model Objects amount: min = {1}, max = {null}
• Relationships amount: min = {null}, max = {0}
• Supported Term Data Types: exclude Default Terms = {true}, exclude Business Keys = {false}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}
• Supported Historization Types: exclude Default Terms = {true}, exclude Business Keys = {true}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}, supported Historization Types = {SCD0, SCD1, SCD2}
• Supported Aggregation Types: exclude Default Terms = {false}, exclude Business Keys = {false}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}, supported Aggregation Types = {None}
• Business Key Terms amount: min = {1}, max = {null}
• Business Key Terms not nullable
• Identity Terms amount: min = {1}, max = {1}
• Identity Terms not nullable
• Supported Implementation Types: supported Implementation Types = {Permanent}
• Historized Source
• ValidFromSourceTerm exists
• ValidFromSourceTerm configured