rusterd

ER diagram DSL compiler that renders to SVG. Written in Rust, compiles to WASM for browser use.

Features

• Entities: Define tables with typed columns
• Column types: int, string, decimal, timestamp, boolean, text
• Constraints: pk, fk -> Entity.column, not null, unique
• Relationships: Support all cardinalities (1, *, 0..1, 1..*)
• Self-references: Entities can reference themselves
• Layout hints: Grid-based positioning with @hint.arrangement
• Views: Filter diagrams with view blocks
• Detail levels: Control what's shown (tables only, pk, pk+fk, all columns)

Example

@hint.arrangement = {
    User;
    Order OrderItem;
    Product
}

entity User {
    id int pk
    email string unique not null
    name string
}

entity Order {
    id int pk
    user_id int fk -> User.id
    total decimal
}

entity Product {
    id int pk
    name string not null
    price decimal
}

entity OrderItem {
    order_id int pk fk -> Order.id
    product_id int pk fk -> Product.id
    quantity int not null
}

rel {
    User 1 -- * Order
    Order 1 -- * OrderItem
    Product 1 -- * OrderItem
}

view simple {
    include User, Order
}

CLI Usage

# Build
cargo build --release

# Render to file
rusterd input.erd -o output.svg

# Render specific view
rusterd input.erd -v simple -o output.svg

# Control detail level
rusterd input.erd -d pk_fk -o output.svg

Detail levels:

• tables - Entity names only
• pk - Primary keys
• pk_fk - Primary and foreign keys
• all - All columns (default)

WASM Usage

# Build
wasm-pack build --target web

# Run demo
cd demo
bun install
bun run dev

import init, { erdToSvg } from 'rusterd';

await init();
const svg = erdToSvg(erdSource);           // Full diagram
const svg = erdToSvg(erdSource, 'simple'); // Specific view
const svg = erdToSvg(erdSource, null, 'pk_fk'); // Detail level

Syntax Reference

Entities

entity EntityName {
    column_name type [constraints]
}

Relationships

rel {
    Entity1 cardinality -- cardinality Entity2 [: "label"]
}

Cardinalities: 1, *, 0..1, 1..*

Layout Hints

# Grid-based arrangement (semicolons separate rows)
@hint.arrangement = {
    Entity1 Entity2;
    Entity3 Entity4
}

# Entity-specific level hint
entity EntityName @hint.level = 2 {
    ...
}

Views

view view_name {
    include Entity1, Entity2, Entity3
}

Examples

See examples/ directory for more samples including:

• Many columns layout
• Deep hierarchies
• Dense relationships
• Unicode/CJK text
• Self-referential entities
• Complex e-commerce schema

License

MIT