SQLlyRelationship Graph
✓ functionalAn interactive ER diagram of the database's tables and foreign keys.
An interactive ER diagram for the database: one card per table, one arrow per foreign key. The arrow always points at the referenced table, so a chain of arrows reads as a chain of dependencies. Open it from a database's right-click Tools menu.
It reads the catalog directly - no modelling step, nothing to keep in sync. What is on screen is what the database says its foreign keys are right now, and Refresh re-reads them.
Choosing what is on the canvas
- Tables - a Tables panel with All / None / FK-connected buttons and a per-table checkbox list. The default view starts from the most-connected tables so a 600-table schema opens as a diagram rather than a hairball; picking tables yourself lifts that cap and can include tables with no relationships at all.
- Filter - type in the filter box to dim everything whose
schema.tabledoes not match. Non-matching tables stay in place, greyed, so you keep the shape of the diagram while you find something in it. - Focus - opened from a table, the diagram shows that table and its immediate neighbours. Show all brings the rest back.
What each card shows
Four switches control the level of detail, independently:
| Switch | Shows |
|---|---|
| Columns | Every column of the table, in ordinal order. Columns that take part in a foreign key are emphasised. Cards are sized to fit the whole list - nothing is truncated. |
| Types | Each column's data type, right-aligned against the card edge so it never collides with a long column name. |
| Nulls | NULL or NOT NULL per column. A column whose nullability the engine did not report says nothing rather than guessing. |
| FKs | The relationship arrows themselves. Off leaves just the table cards. |
Types and Nulls describe a column row, so they only apply while Columns is on. With columns shown, an arrow anchors at the exact column on each side rather than at the edge of the box.
Arranging it
- Layout - Grid is a deterministic row-major arrangement; Layered puts referenced tables to one side of the tables that reference them, which reads better for a hierarchy.
- Width - the − and + buttons resize every table card, and the layout spreads to match so widening cards does not overlap them. Useful when column names or types are long.
- Drag a card to place it by hand; dragged cards keep their position through a layout change. Reset layout puts everything back.
- Zoom and pan - scroll to pan, ⌘-scroll (Ctrl-scroll on Windows and Linux) or pinch to zoom between 25% and 300%, Fit to frame the whole diagram, and the percentage button to return to 100%.
- Pop out the diagram into its own resizable window - carrying its current selection and layout - when you want it beside the editor rather than over it.
- Click a table to reveal it in the schema tree.
Exports
Everything under Export exports what you are looking at - the current table selection, the current layout including any cards you dragged, and the current column/type/nullability switches. Each format can be copied to the clipboard or saved to a file.
| Format | What you get | Good for |
|---|---|---|
| SVG | The diagram exactly as drawn - boxes, arrows, positions, and the current theme's colours - as a vector image. | Dropping into a document, a wiki, or a slide at any size. |
| Mermaid | An erDiagram block: one entity per table with its key columns, one relationship line per constraint. | Markdown that renders itself - GitHub, GitLab, and most wikis draw Mermaid natively, and it stays diffable in review. |
| DBML | A Table block per table with its key columns, plus a Ref per relationship. | Feeding schema tools that read DBML, and keeping a text-first record of the model in version control. |
Mermaid and DBML describe the relationships, not the full schema: they carry the tables and the columns that participate in keys. For complete DDL, script the objects from the explorer instead.
