Entity Relationship Assistant-AI ER diagram generator

Example

From business rules produce: conceptual model, logical model, and diagram code. Example output (textual): Entities: Customer(CustomerID PK, Name, Email), Product(ProductID PK, Name, Price), Order(OrderID PK, OrderDate, CustomerID FK), OrderItem(OrderID FK, ProductID FK, Quantity, PriceAtSale; PK = (OrderID,ProductID)). Relationships: Customer 1—* Order; Order 1—* OrderItem; Product 1—* OrderItem (interpreted as many-to-many Order ⇄ Product via OrderItem). Diagram code examples provided in PlantUML, DBML or Mermaid.

Scenario

Designing an e-commerce order subsystem for a startup: the assistant converts product/checkout requirements into a normalized logical ERD, annotates cardinalities and optionalities, and emits PlantUML for the engineering team’s wiki and DBML for the schema migration pipeline. It also provides a short checklist of acceptance tests (e.g., enforce non-null customer email, unique product SKUs, cascade rules for soft deletes).

Example

Take a flat 'Orders' CSV with duplicated customer columns and repeated product columns. The assistant will: (a) propose a normalized 3NF model (separate Customer and Product tables, associative OrderItem), (b) show transformation SQL/pseudocode to split fields, and (c) if required, propose denormalization (pre-joined materialized view or a denormalized reporting table) with trade-offs (storage vs write complexity vs read speed).

Scenario

A legacy CRM has a single table with repeated phone columns and address text blobs. The assistant prescribes a normalized contact and address model, recommends unique constraints, proposes a canonical contact identifier strategy, and, for read-heavy reporting, offers a CQRS approach: keep normalized OLTP tables and build denormalized, indexed reporting tables refreshed via scheduled jobs or CDC.

Example

Generate dialect-specific SQL DDL (PostgreSQL, MySQL, SQL Server): CREATE TABLE definitions, PK/FK constraints, UNIQUE constraints, CHECK constraints, recommended indexes, and sample migration steps. Example snippet: CREATE TABLE OrderItem (OrderID UUID NOT NULL, ProductID UUID NOT NULL, Quantity INT NOT NULL CHECK (Quantity>0), PriceAtSale NUMERIC(10,2) NOT NULL, PRIMARY KEY (OrderID,ProductID), FOREIGN KEY (OrderID) REFERENCES "Order"(OrderID), FOREIGN KEY (ProductID) REFERENCES Product(ProductID));

Scenario

Migrating a MyISAM-based MySQL schema to PostgreSQL: the assistant produces a converted DDL, highlights incompatible types (e.g., unsigned ints), replaces MySQL-specific features, suggests sequence/identity handling, provides an ordered migration plan (create schema, copy static lookup tables, bulk copy large tables with minimal locking, apply foreign keys, run verification queries) and sample verification SQL to compare row counts and checksums.