Is there diagram for dynamoDB schema like ER diagram for RDBMS?

Question

I'd like to write documentations of my dynamodb schema.

Is there some diagram for document or should I use ER diagram?

Answer 1

I think it's a good practice to define an ER diagram. You will establish the entities and their relationship to one another in a DB agnostic way.

While you are at it, I'd suggest creating a document that lists:

• Access Patterns - For example, fetch users by email, fetch orders by status, etc.
• Describe your primary key structure - What are you Primary Key(PK) and Sort Key(SK) patterns? For example PK ORDER# defines the Order entity, USER#<email_address> defines the USER entity, etc.
• Describe any secondary indexes (PK/SK patterns)

Check out how Alex DeBrie models his examples in his AWS talk for a good example.

ER diagrams are a fantastic reference to understand the data model, and I think every database should have one as a part of it's documentation. With DynamoDB, understanding the access patterns and how the Primary Keys are designed to support the access patterns is critical information.