Diagram summary
Project settings
Interactive diagram
Drag entities to reposition them. Relationship lines update automatically.
Entities and attributes
Relationships
Import and tools
Generated SQL
How an ER Diagram Generator helps
An ER Diagram Generator turns database planning into a visual workflow. Instead of keeping table ideas in scattered notes, you can define entities, attributes, keys, and relationships together. This makes structure easier to review before development starts. A visual model also helps teams notice missing foreign keys, inconsistent naming, duplicate fields, and unclear ownership. By moving entities around the canvas, designers can group related areas and make large schemas easier to understand.
Designing entities and relationships
Begin with the main objects your system stores. Common examples include customers, orders, products, users, courses, or invoices. Add attributes for each object, then choose suitable data types. Mark primary keys first because every important entity should have a reliable identifier. Next, connect foreign keys to their parent entities. Cardinality describes how many records can participate in each relationship. One-to-many relationships are common in business systems. Many-to-many relationships normally require a linking entity containing foreign keys from both sides.
Validation and SQL generation
Schema validation catches design problems before they reach production. This generator checks missing primary keys, invalid references, duplicate names, incompatible key types, orphan entities, and circular relationships. SQL generation then converts the visual model into table definitions and constraints. You can choose a database dialect and copy the generated statements into your development workflow. Imported SQL or JSON can also rebuild a diagram, which is useful when documenting an existing project.
Exporting documentation
CSV exports provide a compact data dictionary for reviews. JSON preserves the editable model for later reuse. PDF export captures the diagram, project details, and schema summary in a portable document. These formats help developers, analysts, clients, and students share database decisions. It also simplifies onboarding for new contributors. Good diagrams reduce misunderstandings and keep documentation synchronized with implementation. Clear schema planning makes later database changes significantly safer.
Example schema documentation
| Entity | Attribute | Data type | Key type | Nullable | Related entity |
|---|---|---|---|---|---|
| customers | id | INT | Primary key | No | orders |
| customers | VARCHAR(190) | Unique | No | — | |
| orders | customer_id | INT | Foreign key | No | customers |
| orders | total | DECIMAL(10,2) | — | No | — |