Data API Builder Deployment Error – Primary Key Requirement

[Koro110]

When deploying to the MCP server following the reference guide below,
I observed a deployment error occurs if no primary key is defined in dab-config.json.

Azure.DataApiBuilder.Service.Exceptions.DataApiBuilderException:
Primary key not configured on the given database object <table_name>.

Would this be considered a mandatory requirement?

Reference:
https://learn.microsoft.com/ja-jp/azure/data-api-builder/mcp/quickstart-azure-container-apps?tabs=windows

[JerryNixon]

Yes, it is considered mandatory. Let me explain why we require it.

1. Pagination in DAB is cursor-based, not index-based. It uses a combination of the key, filter, and sort instructions so a busy table has consistent and stable paging. We don’t currently support index-based paging.
2. Relationships between tables in Data API builder are managed, like in the database, between a foreign key column in the target table and the primary key in the source. We don’t support tables that cannot be related.
3. Create, update, and delete operations are available for every table in DAB. For CRUD to work, we must have a primary key. We don’t currently support read-only entities.

Right now, primary keys are required. When you indicate a column is a key, the database does not need a matching key constraint. You can also use more than one column if it makes sense for your table. In either case, a key is required and important.

[Koro110]

Thank you for the explanation, Jerry Nixon.
I understand that in DAB it is sufficient to declare a column (or a combination of columns) as a logical unique identifier, and that the database itself does not need to enforce a key constraint.
Even if the data is not unique on the database side, it is still possible to configure such columns as a key in DAB.