Starting From Scratch: Designing a Schema with AI Designer
From SQL to Diagram assumes you already have a CREATE TABLE dump to paste. This article covers the other on-ramp: no SQL, no existing schema, just a description of what you’re trying to build. Both paths land in the same place — a reviewable diagram you can keep editing, analyze, and save like any other schema.
1. Open a new schema
Same starting point as always — opening a new schema from a project drops you into DDL mode. With nothing pasted yet, the “Import DDL” pane shows a callout: “Don’t have DDL yet? Describe what you want to build and let AI Designer draft the schema for you” — with a Use AI Designer button.
2. Describe what you’re building
Clicking it switches straight to the AI Designer tab. The canvas is empty — a note points you at the chat panel on the right — and the panel itself is ready for input immediately; there’s no “paste something first” gate. Describe the thing you want in plain language, the way you’d explain it to a person: “a simple blog with posts and authors,” “inventory tracking for a small warehouse with suppliers and purchase orders,” “a booking system for a single-location gym.” The more concrete the description, the more useful the first draft — but you don’t need to get it right in one message, since follow-ups can refine it (see step 4 below).
3. Review the draft
Send it, and Gemini designs a complete, sensible set of tables, columns, primary/foreign keys, and relationships from nothing — not evolving anything, since there’s nothing yet to evolve. The result renders directly on the canvas, every table highlighted as new, alongside a short rationale in the chat explaining what it added and why. This is the same proposal mechanism AI Designer uses when refining an existing schema — the only difference here is the starting point.
4. Refine, confirm, and treat it like any other schema
Send a follow-up (“also track payment status on each order”) to keep building on the same draft, the same way you would on an existing schema. Once you’re happy, Confirm folds it into your real working schema — from that point on it behaves exactly like a schema you’d pasted DDL for: switch to DDL mode to see and hand-edit the generated SQL, explore the diagram, run AI Schema Analysis against it, and use the top-bar Save button to persist it to your project — nothing above that button writes to your account automatically, same as the SQL-first path.