Editing DDL on a Saved Schema

From SQL to Diagram covers the first save. Once a schema has been saved and reopened, DDL mode looks almost identical but behaves a little differently — the heading changes from “Import DDL” to “Modify DDL,” and the textarea now tracks a baseline so it can show you what’s changed before you commit to it.

Everything happens in the same textarea

There’s no separate “Add Table” box — pasting one or more additional CREATE TABLE statements straight into the existing DDL, alongside what’s already there, is the whole mechanism. Editing an existing table’s columns works the same way: change the text, then re-analyze.

Seeing what you’ve changed before you save it

Once a schema has been analyzed at least once, any line that differs from the last-analyzed baseline gets a green-tinted background live as you type — so a newly pasted table, or an edited column definition, is visible immediately instead of something you’d have to diff manually before committing. This overlay only tracks the current editing session; a first-time paste on a brand-new schema isn’t highlighted, since there’s no baseline yet to compare against.

Committing the change

Click Save & Update to re-parse the DDL and run relationship inference and gap detection again. This does two things at once:

• Any table that’s new since the last analysis renders on the canvas with the same blue highlight used for an unconfirmed AI Designer proposal, until your next Save
• The green unsaved-edit overlay clears, since the DDL you just analyzed becomes the new baseline — tables that didn’t change keep their manual position, sticky notes, and expanded/collapsed column state rather than resetting

As always, Save & Update only updates the working diagram in your current session — it doesn’t write anything to your account. Use the top-bar Save button afterward, which opens the usual Update Existing vs. Save as New confirmation (see Projects, Collections, and Saved Schemas) if you’re saving over a schema that already exists.

Changing the dialect later

The dialect picker stays editable in Modify DDL the same way it is on a new schema — switching it just updates the descriptive metadata saved with the schema (see Supported SQL Dialects and DDL Syntax); it doesn’t reparse anything or affect the diff overlay.