Table Groups

A table group is a named, colored box drawn behind related tables on the ERD canvas, to show which tables belong together.
A table is in one group at most. Groups are saved with the diagram, along with which group each table is in.

The box has a title bar along its top, holding a group icon, the group's name in bold, and, while the pointer is over the group, an x that removes it — see Removing a Group. A group with no name reads unnamed, and a name too long for the bar is cut short with ….
The box always holds its tables: it keeps the size it was given, but stretches to keep each table inside with 24px of room around it and the title bar above. A table that grows stretches the box with it, and so does a table dropped near an edge with its center still inside the box. While tables are being dragged, the box neither grows nor shrinks. The stretch is not saved: the box goes back to its own size once the table no longer needs the room.

Groups are drawn behind everything else on the canvas: tables, memos, and relationship lines.
Where groups overlap, the one pressed or added last is drawn in front, and no group's body ever covers another group's title bar. The order is not saved, so a reopened diagram stacks its groups in the order they were added.
Groups show on the ERD canvas, in the minimap, and in an exported image. The Visualization tab draws no groups and no group colors in either mode.

A coding agent can create and change groups too, and read the DDL of chosen groups — see Table Groups in the MCP tools.

Creating a Group

There are two ways to create a group. Neither has a shortcut or a canvas toolbar button, and neither is offered in a read-only editor or while groups are hidden.

Drawing a Group

Choose New Table Group from the canvas context menu, where it follows New Table and New Memo, or from Quick Search on the ERD tab. Then drag a box over the canvas.
While the draw is armed, the cursor is a crosshair, and a press starts the box wherever it lands, even over a table, rather than selecting or moving what is under it. The canvas toolbar then marks neither the hand nor the pointer.

Releasing adds a group in that box, never smaller than 160px wide and 100px tall, title bar included, however short the drag. A click without dragging adds a group 480px wide and 320px tall with its top-left corner at the click.
Every table in no group whose center lies inside the new box joins the group. A table already in another group stays there.

The middle mouse button still pans the canvas and leaves the draw armed. These end the draw without adding a group:

• Escape, before the press or during the drag. Before the press it leaves the selection as it is; the press that starts the box has already cleared it.
• A right-click, which clears the selection. No context menu opens.
• Switching to the hand tool with Space or the canvas toolbar, clicking the toolbar's pointer, or starting a relationship.
• Switching to another tab, hiding the groups, or the editor turning read-only.

Grouping Selected Tables

Select one or more tables, then choose Group selected tables from a table's context menu, or Group Selected Tables from Quick Search, which lists it while a table is selected.
The new group is drawn round the selected tables with 24px of room on every side and the title bar above. Every selected table joins it, leaving any group it was in, and the group it left stays, even if it is now empty. Memos in the selection are passed over.

Either way, the new group has no name and no color. It is selected on its own, and its name editor opens over the title bar so you can type a name at once — see Naming a Group.
The group and the tables it takes in are one undo step, and the name you type is another.

Naming a Group

A group's name is edited in a field that opens over its title bar. It opens on its own once a group is created, on a double-click on the title bar, and from Rename in the group's context menu.
Enter, or clicking elsewhere, saves the name. Escape closes the field without changing the name and leaves the group selected, and a second Escape clears the selection.
A changed name is one undo step; saving the name unchanged records nothing. An empty or blank name shows as unnamed.
While the field is open, the canvas shortcuts are held back, and the Quick Search and Find and Replace shortcuts open nothing, as while a table cell is edited.

Group names are not searched by Quick Search or Find and Replace.

Coloring a Group

Choose Color in the group's context menu to open the color picker on the group's color.
As with tables and memos, the picker colors every selected table, memo, and group, and Remove color in the menu, or the picker's No color, takes the color off all of them — see Table and Memo Color Specification. A group's color is also offered under the picker's Document colors.

A colored group draws its title bar and outline in the color and its body in a pale tint of it. A group with no color uses the theme's neutral grays.
Every table in a colored group wears the group's color across its header and keeps its own color on its left edge, so both show.
The text and buttons on such a header turn white, or black on a light color where black reads far better, as do the name, icon, and x on the group's title bar. Among the picker's preset swatches, Orange, Amber, Yellow, and Lime take black, and the rest take white.
A table keeps its own header while its group has no color, while groups are hidden, at 70% zoom and below, where tables collapse to their name, and on the Visualization tab.

A color change is recorded in the undo history as it is for tables and memos.

Selecting Groups

Click a group's title bar to select the group on its own, or Ctrl + click (Windows/Linux) or ⌘ + click (Mac) to add it to the selection.
Pressing the title bar of a group that is already selected keeps the whole selection, so a drag then moves all of it.
Pressing the title bar, or right-clicking the group, brings the group in front of the other groups and its tables in front of every other table and memo.

The body, the area under the title bar, is the canvas to the left mouse button: dragging it pans, Ctrl + drag (Windows/Linux) or ⌘ + drag (Mac) draws a selection box, and a click clears the selection. The tables, memos, and relationship lines over the body answer to the pointer as usual.

A selection box takes a group only when it encloses the group's whole box, so a box drawn inside a group picks out tables without the group — see Multiple Selection.
Ctrl + A (Windows/Linux) or ⌘ + A (Mac) never selects a group.

Select tables in the group's context menu replaces the selection with the group's tables, leaving the group itself out, so the next command reaches only the tables.
Use it before commands that act on tables alone, such as copying or focusing on tables, which pass over a selected group.

A selected group's outline turns the selection color. In a collaborative session, a group another participant selects is ringed in that participant's color.

Moving and Resizing a Group

Drag a group by its title bar to move it with all of its tables.
If the group is part of a larger selection, the whole selection moves with it, and a table that is both selected and in the group moves once.
The drag starts only once the pointer has moved a short way, so a click or double-click on the title bar stays a click. Alt + drag on a title bar moves the group as a plain drag does; a group is never duplicated.
The move, with every table it carries, is one undo step.

Dragging a table on its own moves only that table, and can move it into or out of a group — see Adding and Removing Tables.

Every group has resize handles on its four edges and four corners, selected or not, as a memo does.
Drag one with the left mouse button: the box follows the pointer, and the new size is saved when you let go, as one undo step.
A group cannot be made smaller than 160px by 100px, nor smaller than its tables with their 24px of room and the title bar. The edge stops there however far the pointer goes.

Adding and Removing Tables

A table joins or leaves a group where you drop it.
When you drag tables and let go, each dragged table that is not carried by a selected group is judged by its center. It joins the topmost group whose box holds its center, or leaves its group if its center lies in no group's box. The topmost group is the one drawn in front.
A group the drag leaves in place keeps the box it had when the drag began, so a table nudged within its own group stays in it, and has to be dragged until its center is outside that box to leave.
While you drag, each group the drop would put a table in is outlined.

When you let go within about 200ms of the last movement, the change of group is part of the drag's undo step, so one undo puts the tables back where they were and in the groups they were in. After a longer pause before letting go, the change of group is a step of its own — see One Gesture, One Step.
A click, or a drag of a few pixels, changes no group, and nothing changes group while groups are hidden.

The other ways to change which tables a group holds:

• Remove from group in a table's context menu takes every selected table out of its group. It shows while a selected table is in a group, even while groups are hidden, and is one undo step.
• Group selected tables moves the selected tables into a new group — see Grouping Selected Tables.
• Removing a group leaves its tables in no group.

A table pasted or duplicated with Alt is in no group, even when it lands inside a group's box. Dragging it afterwards applies the drop rule.

Removing a Group

Removing a group never removes its tables: they stay where they are, in no group.

• The x at the end of the title bar, which shows while the pointer is over the group, removes that group alone.
• Delete in the group's context menu removes the group. When the group is one of several selected items, the row reads Delete selected and removes everything selected: tables, memos, and groups.
• With groups selected, Delete or Backspace removes the selected groups along with any selected tables and memos, as do Ctrl + Backspace and Ctrl + Delete (Windows/Linux) or ⌘ + Backspace and ⌘ + Delete (Mac) — see Table and Memo Deletion.

Each removal is one undo step, which brings the group back with its tables in it.

The Group Menu

Right-click a group's title bar, body, or edge to open its menu. On a Mac, Ctrl + click opens it too, and so does a long press on a touch screen.
The right-click selects the group first, alone unless it is already part of the selection, so Color and Delete selected reach the rest of the selection only when the group was in it.

• Select tables: selects the group's tables alone — see Selecting Groups.
• Rename: opens the name editor — see Naming a Group.
• Color: opens the color picker — see Coloring a Group.
• Remove color: shown while something selected has a color.
• Delete, or Delete selected when the group is one of several selected items, with the Delete key shown on the right — see Removing a Group.

A table's context menu adds Group selected tables and Remove from group after Color and Remove color, before its Delete row, and the canvas context menu adds New Table Group.

Hiding Groups

View Option → Table Groups in the canvas context menu shows or hides every group. It is checked by default — see Table View Options.
Unchecked, the group boxes and the group colors on table headers disappear from the canvas, the minimap, and exported images, and the scrollbars and minimap no longer make room for the groups. Nothing moves or resizes, and every table stays in its group.
Hiding the groups deselects them, ends a New Table Group draw, and closes an open name editor.

While groups are hidden:

• New Table Group and Group selected tables are not offered in the menus, nor New Table Group and Group Selected Tables in Quick Search. Remove from group still is.
• Dragging tables changes no group, and a selection box takes no group.
• Auto Layout still keeps each group's tables together, the Schema SQL tab still offers the groups to choose from, DBML still writes them, and Import and Add still lands below the hidden boxes.

The choice is saved in the document and recorded in the undo history, like the other View Option toggles.

Auto Layout

Every Auto Layout keeps each group's tables together, whether or not groups are shown.

• Force moves each group with its tables as one box, the tables keeping their places inside it, and keeps each group's box at least 100px from other groups and from tables in no group. The preview shows each group where it is going.
• Flow, Tree - vertical, and Tree - horizontal lay out each group's tables inside the group and place the groups by the relationships between them, with the tables in no group laid out around them.

Afterwards each group that holds tables is fitted to them: its box becomes their bounds with 24px of room and the title bar. A group with no tables keeps its place and size.
The tables and groups land as one undo step.

A DBML import fits each group round its tables in the same way, wherever they are placed — see DBML.

Schema SQL by Group

The Schema SQL tab can write the tables of chosen groups alone.
While the document holds a group, shown or hidden, its options panel shows a Tables row under This window only, with a box for All, one for each group, and one for No group, the tables in no group — see Tables.
The choice belongs to the editor window and is not saved in the document.

Import, Export, and Copying

• DBML carries groups both ways. A DBML import turns each TableGroup block into a group — see DBML — and the Code Generator's DBML writes a TableGroup block for each group that holds a table — see Code Generator.
• A JSON file keeps its groups. No other format carries them: SQL, GraphQL, and AML imports bring none, and Schema SQL and the other Code Generator targets write none.
• Import and Add brings a file's groups in as new groups holding their tables, and selects them with the new tables while groups are shown, so dragging the added block carries its groups along.
• An exported image draws the shown groups behind the tables, with the group colors on their headers.
• Copying and pasting, or duplicating with Alt, never copies a group — see Copying/Pasting Tables and Memos and Adding and Removing Tables.

Read-only Editors

In a readonly editor, groups are drawn as usual and can be selected, but not changed:

• A press on a title bar selects the group and moves nothing. There are no resize handles and no x.
• A double-click on the title bar opens no name editor, and the group menu holds Select tables alone.
• The canvas menu has no New Table Group, the table menu has no Group selected tables or Remove from group, and Quick Search lists neither group command. A New Table Group draw ends when the editor turns read-only.
• The Table Groups view option changes nothing, as with every View Option.
• The Schema SQL tab's Tables choice still works.