How to Create ER Diagrams with Claude
Generate ER diagrams with Claude and ToolRouter. Database schema visualization from descriptions.
Tool
Claude builds ER diagrams through an iterative data modeling conversation. Describe your entities and relationships, get the diagram, then refine by adding fields, adjusting cardinality, or including junction tables through follow-up questions. The conversation naturally covers edge cases in your data model that a single description would miss.
Connect ToolRouter to Claude
1Go to Settings → Connectors → Add custom connector
2Enter the details below and click Add
Name
ToolRouterURL
https://api.toolrouter.com/mcp3Done — works on Claude chat, desktop, and mobile
Steps
Once connected (see setup above), use the Diagram Generator tool:
- Ask Claude: "Create an ER diagram using diagram-generator" and describe your data model
- Claude generates the diagram with tables, columns, and relationship lines
- Download the diagram for your database documentation
Example Prompt
Try this with Claude using the Diagram Generator tool
Create an ER diagram for an e-commerce database: Users have many Orders, each Order has many OrderItems, OrderItems reference Products, Products belong to Categories. Show the key columns and foreign keys.
Tips
- Specify cardinality explicitly -- "one user has many orders" vs "users and orders have a many-to-many relationship"
- Ask Claude to include data types and primary/foreign key indicators