Create a Link

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

What is a Link

In a Data Vault modeling, a Link integrates the Business Keys and stores the relationships between them, themselves stored in Hubs (See Create a Hub). 

Creation steps

There are two possibilities to create a Link Model Object:

• Create a Model Object with the Wizard:
  • Recommended possibility
  • Use the Wizard Create a Link from a Stage or a Stage Composite that contains the following steps:
    • Create Model Object
    • Create Dataflow
    • Create Relations: number = {null}
    • Map Foreign Key Terms
    • Add to View
• Create a Model Object manually:
  
  • Create a Model Object of type Link in the Silver Layer
  • Create a Dataflow Set 
  • Add a Model Object to the Dataflow Set: add the Stage or Stage Composite Model Object
  • Add a Relationship to the corresponding Hubs (at least 2 Hubs)
  • Edit the Foreign Key Terms: set them as Business Key
  • Map the Foreign Key Terms: select the target mode and manually map the Foreign Key Terms to the corresponding Source Terms (with or without a complex expression)

Properties

A Link 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 Link Model Object will include the following Default Terms:  

• BG_LoadTimestamp

• Link_HK

• BG_SourceSystem

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 = {2}, max = {null}
• Terms amount: exclude Default Terms = {true}, exclude Business Keys = {true}, exclude Identities = {false}, exclude Foreign Keys = {false}, exclude unmapped Terms = {false}, 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}
• Business Key Terms amount: min = {1}, max = {null}
• Identity Terms amount: min = {1}, max = {1}
• Identity Terms not nullable
• Supported Implementation Types: supported Implementation Types = {Permanent}
• Supported Deduplication Methods: supported deduplication Methods = {None, Distinct, Partition}
• Supported Load Cachings: supported Load Cachings = {Hashing}