Entity Tables (ERD)

Entity Table and Entity Field are two shapes in the Basic Shapes library for drawing entity-relationship diagrams. An Entity Table shows an entity name in its header and a list of field rows with key markers and data types. Connect tables with relationships to show how entities relate.

Add a field, connect two tables, collapse a table

Adding an Entity Table

1. Open the Diagramming panel and expand Shapes > Basic Shapes.
2. Drag Entity Table onto the canvas. It arrives with an example entity and four fields you can rename.

A selected Entity Table: Add field (+), style, reset, lock and more

The Header

• Entity name — double-click to rename.
• Field count — shown in brackets next to the name.
• Collapse arrow — click the triangle to fold the table down to its header, or to expand it again. Relationships stay attached in both states.

Fields

Each row is an Entity Field with three parts:

Part	Meaning
Key marker	PK for a primary key, FK for a foreign key, blank for an ordinary field.
Field name	Double-click to edit.
Type	Free text such as int, string (25) or reference. Double-click to edit.

PK and FK markers, field names and types

To add a field, select the table and click Add field (the +) in the toolbar. The new row takes the styling of its neighbours. You can also drag an Entity Field from the palette into a table.

Use the arrow keys to move between rows of a selected table without leaving the keyboard.

Connecting Tables

Draw a relationship from one table to another exactly as for any shape: select the source table, drag a connector to the target. Use the arrowhead picker on the relationship toolbar to show cardinality, for example a circle-fork for "zero or many". See Relationships.

Tips

• Give every table a PK row first; it keeps the layout consistent across the diagram.
• Collapse tables you are not working on to keep a large model readable.
• Entity Tables are visual shapes. To model ServiceNow tables with live data, use the Metamodel library or bind shapes through the Data Hub.

Related

• Shapes — adding and styling shapes
• Relationships — connectors and arrowheads
• Shape Libraries — where Entity Table lives