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ERD Generator

AI ERD generator — diagrams from plain English

Describe your domain and OffDataAI draws the entity-relationship diagram for you: entities, attributes, primary and foreign keys, and correct cardinality. No dragging boxes, no manual layout — and the same model ships as DDL and a dbt project.

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diagram/erd.mmdmermaid · erDiagram
erDiagram
    CUSTOMER ||--o{ ORDER : places
    ORDER ||--|{ ORDER_LINE : contains
    PRODUCT ||--o{ ORDER_LINE : "appears in"

    CUSTOMER {
        string customer_id PK
        string email
        date   created_at
    }
    ORDER {
        string order_id   PK
        string customer_id FK
        date   ordered_at
    }
    ORDER_LINE {
        string order_id   FK
        string product_id FK
        int    quantity
    }
    PRODUCT {
        string product_id PK
        string name
        numeric list_price
    }

Hand-drawing an ERD is slow, and the diagram drifts from the database the moment the schema changes. OffDataAI generates the ERD from a validated data model, so the diagram and the code never disagree. Describe your business in plain English, answer a few clarifying questions about grain and cardinality, and OffDataAI renders a Mermaid entity-relationship diagram with keys and relationships — alongside platform-native DDL and a complete dbt project. Edit the model and the diagram regenerates automatically.

What OffDataAI generates

  • Entities, attributes, and keys

    Every entity is drawn with its attributes, primary keys, and foreign keys — inferred from your description and validated for referential integrity.

  • Correct cardinality

    One-to-many and many-to-many relationships are resolved (with bridge tables where needed) and drawn with proper crow's-foot notation.

  • Mermaid, version-controllable

    Diagrams are text-based Mermaid you can drop into docs, a README, or a pull request — no binary diagram files to maintain.

  • Diagram plus runnable code

    The ERD is generated from the same model that produces DDL and dbt, so the picture always matches what you deploy.

Frequently asked questions

How do I generate an ERD from a description?
Describe your domain in plain English on OffDataAI — for example, 'customers place orders, each order has line items pointing to products.' The interview agent confirms grain and cardinality, then OffDataAI renders an entity-relationship diagram (Mermaid) with entities, attributes, primary and foreign keys, and the relationships between them. The same model also produces DDL and a dbt project.
Does the ERD include keys and cardinality?
Yes. Each entity shows its attributes with primary keys and foreign keys, and relationships are drawn with correct cardinality (one-to-many, many-to-many via bridge tables). Because the diagram is generated from a validated model, the keys and relationships are consistent with the DDL that ships alongside it.
Can I edit the diagram after it's generated?
Yes. The ERD is a view of your underlying data model (the Intermediate Representation). Edit entities, attributes, or relationships and the diagram, DDL, and dbt project all regenerate to match. There's no separate diagram file to keep in sync.
What format is the ERD in?
Diagrams are rendered as Mermaid, so they're text-based, version-controllable, and easy to embed in docs, READMEs, or a GitHub pull request. You can also export the model and downstream artifacts.
Is this an online ERD tool or a desktop app?
OffDataAI is a web app — there's nothing to install. Describe your domain in the browser and get an ERD plus warehouse-ready code in under a minute.

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