This page describes Calíope 1.8, the version I am building right now. 1.7 is on the App Store for the Mac, iPad, iPhone, Apple Watch, Apple TV and Apple Vision Pro. The changelog says which version each feature landed in.
Adds an “Open in Calíope” button to every topic. It only works with the app installed.
Visualize the relationships between tables in a database.
Where it is: Workspace › Tools › ER Diagram
Open the ER Diagram from the workspace navigation bar. Select the database in the top selector and Calíope will load the tables with their columns and existing foreign key relationships.
The diagram displays tables as nodes with columns and data types. Lines between tables represent the foreign keys detected on the server.
On Apple Vision Pro the toolbar also has Open in space, which lays the diagram out in the room around you.
SQL Server
In SQL Server each schema is its own entry in the selector (demo.dbo, demo.rrhh). To see a foreign key that crosses schemas, add the other one with + DB: the line between the two is drawn in amber, as between two databases.
Keywords: ER, entity relationship, diagram, FK, foreign key, relationships, ERD
Zooming in and out — on macOS, the mouse wheel, a two-finger pinch on the trackpad, or the toolbar buttons; on iPad, the pinch or those same buttons. The percentage between the toolbar's − and + shows the current scale, and the shortcuts are ⌘−, ⌘+ and ⌘0. The limits are the same everywhere: 18 % to 400 %, and the button dims once you reach either end.
Panning the canvas — drag over an empty area, everywhere. Over a node, dragging moves the table instead.
Getting the whole diagram back — the Fit to window button (⌘0) frames every table. The diagram also re-fits itself when it opens and when the window is resized.
The Auto layout button rearranges the nodes to minimize overlaps.
Apple Vision Pro: as on iPad, with its own gestures: pinch and move to pan or to move a table, and pinch with both hands to zoom. The buttons and shortcuts are the same.
Keywords: zoom, pan, scroll, zoom in, zoom out, canvas, navigate
Draw a new foreign key relationship between two tables.
Where it is: ER Diagram › context menu › Create FK relationship
Open the context menu on a table — right-click on macOS, press and hold on iPad — and select New FK relation…. A dialog opens to choose the source table and column, and the target table and column. When confirmed, Calíope executes the ALTER TABLE … ADD FOREIGN KEY on the server.
On macOS only, in addition: hold ⌃ (Control) and drag from one table to the target one; a rubber-band line follows the gesture and releasing opens that same dialog. On iPad the gesture does not exist, and the foreign key is created from the context menu.
Apple Vision Pro: look at the table and pinch and hold, as you would touch and hold it on iPad; Control-drag is Mac only.
Keywords: FK, foreign key, create relationship, ALTER TABLE, referential integrity
Keep the arrangement you gave the diagram, one per database.
Where it is: ER Diagram › Save layout
Press Save layout in the ER Diagram toolbar. Where you dragged each table is stored per database, so every diagram keeps its own arrangement.
The next time you open the diagram for that database, the tables come back where you left them. A table with no saved position — the ones of a second database you have just added with + DB, or one created since — is laid out on a grid beside the rest, never on top of them.
Apple Vision Pro: the diagram in the space keeps an arrangement of its own. Save layout in the space's panel saves that one, also per database and only on this device; the button in the toolbar saves this one.
In the ER Diagram toolbar, the Export button offers two formats: PNG (an image, ready to paste into a document or a chat) and PDF (ready for printing or presentation). Each one offers three sizes. On the Mac you choose where to save the file in the system dialog; elsewhere the Share sheet opens, from which you save it to Files or send it.
On the Mac the same formats are also in the canvas context menu, and the diagram can be printed with ⌘P.
Inspect the full structure of a table directly from the diagram.
Where it is: ER Diagram › context menu › Edit table structure
Open the context menu on a table node in the diagram — right-click on macOS, press and hold on iPad — and select Edit table structure. A panel opens showing the complete CREATE TABLE statement for the selected table.
The canvas is a drawing: VoiceOver reads it as a list of tables with their columns, types and keys, and of relationships.
Where it is: Workspace › Tools › ER Diagram
The diagram canvas is a drawing that VoiceOver cannot read, so Calíope offers it as a list. The Tables section has one row per table, with its columns, their types and whether each belongs to the primary key (PK) or to a declared foreign key (FK). If there are relationships, the Relationships section reads each one as “origin → destination”, with database, table and column.
It works the same on every platform.
Keywords: VoiceOver, accessibility, ER diagram, tables, relationships
On Apple Vision Pro, the tables become cards around you and the foreign keys lines between them.
Where it is: ER Diagram › Open in space
On Apple Vision Pro, Open in space in the ER Diagram toolbar lays the diagram out in the room around you, with the Calíope window still in view. Each table becomes a card with its name, its database and its columns, each with its key and its type, and each foreign key a line from its column on one card to its column on the other. While the space is open, the same button reads Close the space.
Layers — each database (each schema) has its own arc around you, with its name above it. A database added with + DB is a second arc behind the first, and a line between the two crosses from one to the other.
With your hand — pinch a card and move it to slide it along its arc; its lines follow it. Tap a card to select it: its lines turn amber, the other lines fade, and a panel beside it lists its relationships and offers Show DDL, which shows its CREATE TABLE read-only. Close, or tapping the card again, lets it go.
Without gestures — the panel in front of you, below eye level, does everything the hand does: Close the space; Arrange, which puts every card back where the diagram in the tab places it, asking first if there are moves you have not saved; Save layout; a switch for each layer under Layers, which hides its cards and their lines; and the Tables list, with a filter. Tapping a row is tapping its card, and its menu has Bring to front, which brings the card right in front of you, and Move to layer…, which changes the arc it stands on, not its database.
Saving — Save layout in that panel keeps the 3D arrangement, one per database and only on this device: it is not synced. The space opens with it next time, and a table without a saved place starts where the diagram in the tab puts it.
The space only reads. Nothing in it changes the server: foreign keys are still created in the tab, with New FK relation….
The space belongs to its session. If the session disconnects or closes, the space closes too and the tab says so. There is one space at a time: opening it from another session closes the first one.
With VoiceOver each card reads its table, its database, how many columns and relationships it has, and then each relationship; with a card selected, the ones related to it say so. Each column is read with its full type and its key. The cards and the panels grow with the text size.
Keywords: Apple Vision Pro, visionOS, space, immersive, 3D, cards, layers, ER diagram, spatial
How many tables the space shows with their lines, how long it takes, and how many databases fit.
Where it is: ER Diagram › Open in space
Lines — with more than 200 tables the space opens with every card but without lines, so that it stays readable and is quick to build. Select a card, with your hand or in the panel's list, and its lines appear. The panel says so while that applies.
Many tables — the cards of a layer are stacked in rows so that none covers another, also with a large text size. While the space is being built, the tab and the panel say how many tables are loading and for how long.
How long it takes — measured with 120 tables and 160 foreign keys: the cards and the lines are in place in about three seconds, and the app uses about 150 MB more memory.
Two databases at most, as in the tab: the main one and the one added with + DB, each on its own layer.
Keywords: Apple Vision Pro, space, limits, tables, lines, performance, memory, two databases
Add a second database to the ER diagram canvas to visualize relationships across databases.
Where it is: ER Diagram › + DB
The ER Diagram can display tables from two databases simultaneously on the same canvas, including foreign keys that cross from one database to the other.
How to add a second database:
1. With the ER Diagram open, select the primary DB in the left selector of the toolbar.
2. Press the + DB button in the toolbar to add a second database.
3. Select the second DB in the new selector that appears.
4. The canvas updates automatically, showing the tables of both databases.
Color coding:
- Blue header — tables from the primary DB.
- Teal header — tables from the second DB.
- Orange arrows — foreign key relationships that cross from one database to the other.
- Regular arrows — relationships within the same database.
Requirement for cross-database relationships:
Foreign keys must be declared on the server: the diagram reads them from the engine's catalog. If cross-database relationships do not appear, verify that the FKs exist formally (not just as naming conventions).
Navigation and export:
All features of the standard ER diagram apply to the multi-database canvas: zoom, pan, auto-layout, save layout, export PNG/PDF, and view table DDL. See the ER Diagram topics for more details.
Available on macOS, iPad, iPhone and Apple Vision Pro.
Keywords: erd, multi-database, cross-database, relationships, second database, foreign key, diagram, multi-db, blue header, teal header, orange arrows