Entity Relationship Diagram (ERD)

Select Star automatically generates ERDs (Entity-Relationship Diagrams) so you can easily see how tables and columns in your data model are connected, whether through joins or foreign key relationships.

How ERDs are calculated

Entity Relationship Diagrams (ERDs) show how tables and columns relate to each other.

In traditional SQL databases, these relationships are usually defined through Primary Key (PK) and Foreign Key (FK) constraints. But many modern data warehouses don’t enforce these constraints, even if they support them. That’s why ERDs in Select Star use more than just metadata.

We determine table and column relationships using two sources:

• Database metadata: PK and FK constraints defined in the schema

• SQL query history: Actual JOIN clauses from past queries, which show how data is really being used—even when no formal constraints exist

This approach highlights not only defined relationships, but also inferred ones based on real usage.

Want more detail? Check out our blog post on Automated Data Documentation and the Entity-Relationship Diagram, where you can read more about this approach.

Table ERD

Every table or view has an associated ERD.

To open it:

1. Go to the Table page

2. Click the ERD button in the header

Multi-Table ERD

To view relationships across multiple tables:

1. Go to the Database or Schema view

2. Select the tables you’re interested in using the checkboxes

3. Click the ERD button in the header

Removing ERD edges

You can remove any edge from the ERD diagram to keep it clean and focused. This is useful when certain joins or relationships are no longer relevant or clutter the view.

To remove a connection from the ERD:

1. Hover over the edge in the diagram

2. Click the edit icon

3. Select Remove Edge and confirm the action

Removing an edge will also remove the associated Foreign Key or JOIN relationship. That connection won’t appear in the ERD again — even if it shows up in future query history. Removed joins also won’t appear in the Popular Joins tab or in warehouse query-based suggestions.