In my experience most AI coding tools can work with databases, especially if you give it an MCP tool to connect to your (development) database. It will generate mermaid er-diagrams by reading from your database catalog, it will generate SQL to create tables, views, etc. It will generate queries, validate them and return data. It will optimize your query performance by running the query, running explain plan, looking into pg_stat_statements (or whatevery your database uses), and propose SQL optimization, indexes to be created. It will also create demo data with realistic use cases like black friday or back to school discounts for prices, etc.

A SQL MCP + mermaid is all you need.

Btw, it can also do an awesome job turning query plans into readable mermaid flow diagrams, adding details to the chart, using color to highlight bottlenecks.

I tried my prompt with Claude and with this tool. There is no discussion with this tool. It just generates (a pretty cool) diagram.

I'll probably stick with Claude for now.

A killer feature would be a discussion loop that slowly refines the model in plaintext before committing to a diagram.

Agreed