ER Diagram

The ER Diagram tool renders the tables and foreign-key relationships in your database as an interactive entity-relationship diagram. It supports PostgreSQL, MySQL/MariaDB, and SQLite.

Opening the diagram

Click the ER Diagram button in the toolbar (the Table icon) above the query editor. The diagram always reflects the database targeted by the active editor tab — if your current tab is scoped to production, the diagram shows production, even when another tab targets a different database.

Table selection

A table selector dialog appears before the diagram renders. Pick which tables to include:

• Check individual tables, or use Select All / Deselect All.
• Filter by schema (PostgreSQL multi-schema databases) using the dropdown.
• Click Show Diagram to generate the layout for your selection.

This scoped approach prevents the freeze that would occur when introspecting every table in a large database — dagre auto-layout runs only on the tables you selected.

Adding more tables

Once the diagram is open, click + Add tables in the toolbar to return to the table selector and add more tables to the existing diagram.

Controls and toolbar

Control	Description
Schema filter	Filter the displayed tables by schema (PostgreSQL only, shown when multiple schemas are present).
Search	Type to filter tables by name. Matching tables and their FK-related tables stay visible.
Compact view	Toggle between all columns and PK/FK columns only. On by default.
PKs only	Show only primary-key columns.
Refresh	Re-fetch schema metadata (drops the 30-second in-memory cache).
Export SVG	Saves the current diagram as an .svg file via the native save dialog.

Navigation

• Pan — click and drag the canvas background.
• Zoom — scroll wheel, or use the zoom controls in the bottom-right corner.
• Select — click a table node to highlight it and its relationships.
• Mini-map — the overview in the bottom-right corner shows your position in the full diagram.

Supported engines

Engine	Introspection method
PostgreSQL	Bulk queries via pg_attribute, pg_index, pg_constraint, and pg_class. Handles public. schema prefix transparently.
MySQL / MariaDB	information_schema tables (COLUMNS, KEY_COLUMN_USAGE, TABLE_CONSTRAINTS).
SQLite	PRAGMA table_info() and PRAGMA foreign_key_list() per table, batched with Promise.all for performance.

Schema data is cached in memory for 30 seconds — re-opening the same set of tables within that window returns instantly without re-querying the database.