Relationships

Critical to any use of the data in tables and views that are cataloged within a data stores (e.g., hive data lake, relational data warehouse, NOSQL databases, etc.), is the ability to correctly and effectively join the information together. One may catalog and curate these join conditions by identifying and managing relationships in your data stores.

Example

In this case we will navigate to the object page of the PurchaseOrder table in the Staging DW database model, and click the Relationships tab.

In this instance there is are a number of relationships defined in the source database by Primary Key -- Foreign Key relationships.

The operation (e.g., PurchaseOrder=>VendorPaymentAddress) describes how the two tables should be joined, i.e., in this case each table has a column named VendorID and the data from these two tables should be joined only where the values in the VendorID column match.

One may see these from the erwin DM model import of the Staging DW model.

Click the List tab on the left and then Joins With.

Add Relationships

After harvesting a model, one may navigate to the object page for any classifier level object (e.g., table, view, entity, etc.) and click the Relationships tab. Here you may add custom relationships (based upon the metamodel) to the object.

Defines

Data documentation type relationships.

ER Destination / Source

In some cases there is little to do as some databases will already have a very complete set of primary/foreign key relationships defined and thus this information is harvested as relationships in the model, such as the first one above between the PurchaseOrder and Vendor tables. Again, these are allowed by the metamodel.

Others

Any other relationships defined in the metamodel.