ER Diagram Template

Design your database schema visually. Define tables, fields, and relationships between entities before writing a single line of SQL.

Use this template

What you get

Table blocks with field type annotations
PK / FK labels for quick reference
Relationship connectors between tables

What this template is for

This ER diagram template gives you a starting point for mapping the entities, attributes, and relationships in any relational database. Use it to design a schema before you write migrations, communicate a data model to stakeholders, or document an existing database for a new team member. An entity-relationship diagram makes foreign keys and join conditions visible at a glance — which is far faster than reading a schema dump or asking the person who built it.

When to use this template

Design a new application's database schema before writing the first migration.
Document an existing production database so new engineers can understand the data model.
Communicate a proposed schema change to a technical lead or architect for review.
Map the relationships between tables when debugging a slow query or missing join.
Plan a multi-tenant SaaS schema with tenant isolation boundaries drawn explicitly.
Model an e-commerce database with products, orders, customers, and inventory tables.

How to use it

1Identify the main entities — the things your system needs to store, such as User, Order, or Product.
2List the key attributes of each entity and mark the primary key.
3Draw a line between entities that are related; label the relationship verb (places, contains, belongs to).
4Add cardinality notation to each relationship: one-to-one, one-to-many, or many-to-many.
5For many-to-many relationships, add a junction table with its own primary key and foreign keys.