SQL Tables

Basics

You can easily diagram entity-relationship diagrams (ERDs) in D2 by using the sql_table shape. Here's a minimal example:

Each key of a SQL Table shape defines a row. The primary value of each row defines its type.

The constraint value of each row defines its SQL constraint. D2 will recognize and shorten:

constraint	short
primary_key	PK
foreign_key	FK
unique	UNQ

But you can set any constraint you'd like. It just won't be shortened if unrecognized.

Foreign Keys

Here's an example of how you'd define a foreign key connection between two tables:

If you hover over the primary key or foreign key with your cursor, you'll notice that the corresponding key is highlighted.

Example

Like all other shapes, you can nest sql_tables into containers and define edges to them from other shapes. Here's an example: