Create a Reference Table

A Model Object of type Reference Table can be created in the Silver Layer.

What is a Reference Table

In a Data Vault model, a Reference Table prevents redundant storage of simple reference data that is referenced a lot.

Especially if we don't need historization, we will create a Reference Table instead of a Hub and a Satellite.

Reference tables are referenced from Satellites but always bear physical foreign keys.

Creation steps

There are two possibilities to create a Reference Table Model Object:

• Create a Model Object with the Wizard:
  • Recommended possibility
  • Use the Wizard Create a Reference Table from a Stage or a Stage 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:
  • Not recommended possibility
  • Create a Model Object of type Reference Table in the Silver Layer
  • Create a Dataflow Set
  • Add a Model Object to the Dataflow Set: Add the Stage Model Object
  • Auto-map the Source Terms: Select the auto-map mode and auto-map all the Source Terms in the Source Model Object

Properties

A Reference Table Model Object can be configured through the following Properties: 

• Implementation Type

• Deduplication Method or Optimization Method (Only for Spark Generator)

• Deduplication Partition or Optimization Method Columns (Only for Spark Generator)
• File format (Only for Spark Generator)

Default Terms

A Reference Table Model Object will include the following Default Terms:  

• BG_LoadTimestamp

• BG_SourceSystem
• BG_RowHash

Business Rules

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

• Dataflows amount: min = {1}, max = {null}
• Dataflow Sets amount: min = {1}, max = {null}
• Dataflow Set Model Objects amount: min = {1}, max = {null}
• Relationships amount: min = {null}, max = {0}
• Terms amount: exclude Default Terms = {true}, exclude Business Keys = {false}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}, min = {1}, max = {null}
• Supported Term Data Types: exclude Default Terms = {true}, exclude Business Keys = {false}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}
• Supported Term Data Types: exclude unmapped Terms = {true}, Term name = {IncrementalFilter}
• Supported Implementation Types: supported Implementation Types = {Cached, Virtual}
• Implementation Type Incremental Filter
• Supported Deduplication Methods: supported deduplication Methods = {None, Distinct, Partition}