Georm
A simple, type-safe SQLx ORM for PostgreSQL
## Overview
Georm is a lightweight, opinionated Object-Relational Mapping (ORM) library built on top of [SQLx](https://crates.io/crates/sqlx) for PostgreSQL. It provides a clean, type-safe interface for common database operations while leveraging SQLx's compile-time query verification.
### Key Features
- **Type Safety**: Compile-time verified SQL queries using SQLx macros
- **Zero Runtime Cost**: No reflection or runtime query building
- **Simple API**: Intuitive derive macros for common operations
- **Relationship Support**: One-to-one, one-to-many, and many-to-many relationships
- **Composite Primary Keys**: Support for multi-field primary keys
- **Defaultable Fields**: Easy entity creation with database defaults and auto-generated values
- **PostgreSQL Native**: Optimized for PostgreSQL features and data types
## Quick Start
### Installation
Add Georm and SQLx to your `Cargo.toml`:
```toml
[dependencies]
sqlx = { version = "0.8.6", features = ["runtime-tokio-rustls", "postgres", "macros"] }
georm = "0.1"
```
### Basic Usage
1. **Define your database schema**:
```sql
CREATE TABLE authors (
id SERIAL PRIMARY KEY,
name VARCHAR(100) NOT NULL,
email VARCHAR(255) UNIQUE NOT NULL
);
CREATE TABLE posts (
id SERIAL PRIMARY KEY,
title VARCHAR(200) NOT NULL,
content TEXT NOT NULL,
published BOOLEAN DEFAULT FALSE,
author_id INT NOT NULL REFERENCES authors(id),
created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
);
```
2. **Define your Rust entities**:
```rust
use georm::Georm;
#[derive(Georm)]
#[georm(table = "authors")]
pub struct Author {
#[georm(id)]
pub id: i32,
pub name: String,
pub email: String,
}
#[derive(Georm)]
#[georm(table = "posts")]
pub struct Post {
#[georm(id)]
pub id: i32,
pub title: String,
pub content: String,
pub published: bool,
#[georm(relation = {
entity = Author,
table = "authors",
name = "author"
})]
pub author_id: i32,
pub created_at: chrono::DateTime,
}
```
3. **Use the generated methods**:
```rust
use sqlx::PgPool;
async fn example(pool: &PgPool) -> sqlx::Result<()> {
// Create an author
let author = Author {
id: 0, // Will be auto-generated
name: "Jane Doe".to_string(),
email: "jane@example.com".to_string(),
};
let author = author.create(pool).await?;
// Create a post
let post = Post {
id: 0,
title: "Hello, Georm!".to_string(),
content: "This is my first post using Georm.".to_string(),
published: false,
author_id: author.id,
created_at: chrono::Utc::now(),
};
let post = post.create(pool).await?;
// Find all posts
let all_posts = Post::find_all(pool).await?;
// Get the post's author
let post_author = post.get_author(pool).await?;
println!("Post '{}' by {}", post.title, post_author.name);
Ok(())
}
```
## Advanced Features
### Composite Primary Keys
Georm supports composite primary keys by marking multiple fields with `#[georm(id)]`:
```rust
#[derive(Georm)]
#[georm(table = "user_roles")]
pub struct UserRole {
#[georm(id)]
pub user_id: i32,
#[georm(id)]
pub role_id: i32,
pub assigned_at: chrono::DateTime,
}
```
This automatically generates a composite ID struct:
```rust
// Generated automatically
pub struct UserRoleId {
pub user_id: i32,
pub role_id: i32,
}
// Usage
let id = UserRoleId { user_id: 1, role_id: 2 };
let user_role = UserRole::find(pool, &id).await?;
```
**Note**: Relationships are not yet supported for entities with composite primary keys.
### Defaultable and Generated Fields
Georm provides three attributes for handling fields with database-managed values:
#### `#[georm(defaultable)]` - Optional Override Fields
For fields with database defaults that can be manually overridden:
```rust
#[derive(Georm)]
#[georm(table = "posts")]
pub struct Post {
#[georm(id, defaultable)]
pub id: i32, // Auto-generated serial
pub title: String,
#[georm(defaultable)]
pub published: bool, // Has database default (false)
#[georm(defaultable)]
pub created_at: chrono::DateTime, // DEFAULT NOW()
pub author_id: i32,
}
```
#### `#[georm(generated)]` - Generated by Default
For PostgreSQL `GENERATED BY DEFAULT` columns that can be overridden but are typically auto-generated:
```rust
#[derive(Georm)]
#[georm(table = "products")]
pub struct Product {
#[georm(id, generated_always)]
pub id: i32, // GENERATED ALWAYS AS IDENTITY
#[georm(generated)]
pub sku_number: i32, // GENERATED BY DEFAULT AS IDENTITY
pub name: String,
pub price: sqlx::types::BigDecimal,
}
```
#### `#[georm(generated_always)]` - Always Generated
For PostgreSQL `GENERATED ALWAYS` columns that are strictly managed by the database:
```rust
#[derive(Georm)]
#[georm(table = "products")]
pub struct Product {
#[georm(id, generated_always)]
pub id: i32, // GENERATED ALWAYS AS IDENTITY
pub name: String,
pub price: sqlx::types::BigDecimal,
pub discount_percent: i32,
#[georm(generated_always)]
pub final_price: Option, // GENERATED ALWAYS AS (expression) STORED
}
```
#### Generated Structs and Behavior
Both `defaultable` and `generated` fields create a companion `Default` struct:
```rust
use georm::Defaultable;
let product_default = ProductDefault {
name: "Laptop".to_string(),
price: BigDecimal::from(999),
discount_percent: 10,
sku_number: None, // Let database auto-generate
// Note: generated_always fields are excluded from this struct
};
let created_product = product_default.create(pool).await?;
```
#### Key Differences
| Attribute | INSERT Behavior | UPDATE Behavior | Use Case |
|--------------------|------------------------------------|-----------------|----------------------------------------------|
| `defaultable` | Optional (can override defaults) | Included | Fields with database defaults |
| `generated` | Optional (can override generation) | Included | `GENERATED BY DEFAULT` columns |
| `generated_always` | **Excluded** (always generated) | **Excluded** | `GENERATED ALWAYS` columns, computed columns |
#### Important Notes
- **`generated_always` fields are completely excluded** from INSERT and UPDATE statements to prevent database errors
- **`generated` and `generated_always` cannot be used together** on the same field
- **`generated` fields behave like `defaultable` fields** but are semantically distinct for future enhancements
- **Option types cannot be marked as `defaultable`** to prevent `Option>` situations
### Relationships
Georm supports comprehensive relationship modeling with two approaches: field-level relationships for foreign keys and struct-level relationships for reverse lookups.
#### Field-Level Relationships (Foreign Keys)
Use the `relation` attribute on foreign key fields to generate lookup methods:
```rust
#[derive(Georm)]
#[georm(table = "posts")]
pub struct Post {
#[georm(id)]
pub id: i32,
pub title: String,
#[georm(relation = {
entity = Author, // Target entity type
table = "authors", // Target table name
name = "author", // Method name (generates get_author)
remote_id = "id", // Target table's key column (default: "id")
nullable = false // Whether relationship can be null (default: false)
})]
pub author_id: i32,
}
```
**Generated method**: `post.get_author(pool).await? -> Author`
For nullable relationships:
```rust
#[derive(Georm)]
#[georm(table = "posts")]
pub struct Post {
#[georm(id)]
pub id: i32,
pub title: String,
#[georm(relation = {
entity = Category,
table = "categories",
name = "category",
nullable = true // Allows NULL values
})]
pub category_id: Option,
}
```
**Generated method**: `post.get_category(pool).await? -> Option`
#### Struct-Level Relationships (Reverse Lookups)
Define relationships at the struct level to query related entities that reference this entity:
##### One-to-One Relationships
```rust
#[derive(Georm)]
#[georm(
table = "users",
one_to_one = [{
entity = Profile, // Related entity type
name = "profile", // Method name (generates get_profile)
table = "profiles", // Related table name
remote_id = "user_id", // Foreign key in related table
}]
)]
pub struct User {
#[georm(id)]
pub id: i32,
pub username: String,
}
```
**Generated method**: `user.get_profile(pool).await? -> Option`
##### One-to-Many Relationships
```rust
#[derive(Georm)]
#[georm(
table = "authors",
one_to_many = [{
entity = Post, // Related entity type
name = "posts", // Method name (generates get_posts)
table = "posts", // Related table name
remote_id = "author_id" // Foreign key in related table
}, {
entity = Comment, // Multiple relationships allowed
name = "comments",
table = "comments",
remote_id = "author_id"
}]
)]
pub struct Author {
#[georm(id)]
pub id: i32,
pub name: String,
}
```
**Generated methods**:
- `author.get_posts(pool).await? -> Vec`
- `author.get_comments(pool).await? -> Vec`
##### Many-to-Many Relationships
For many-to-many relationships, specify the link table that connects the entities:
```sql
-- Example schema for books and genres
CREATE TABLE books (
id SERIAL PRIMARY KEY,
title VARCHAR(200) NOT NULL
);
CREATE TABLE genres (
id SERIAL PRIMARY KEY,
name VARCHAR(100) NOT NULL
);
CREATE TABLE book_genres (
book_id INT NOT NULL REFERENCES books(id),
genre_id INT NOT NULL REFERENCES genres(id),
PRIMARY KEY (book_id, genre_id)
);
```
```rust
#[derive(Georm)]
#[georm(
table = "books",
many_to_many = [{
entity = Genre, // Related entity type
name = "genres", // Method name (generates get_genres)
table = "genres", // Related table name
remote_id = "id", // Primary key in related table (default: "id")
link = { // Link table configuration
table = "book_genres", // Join table name
from = "book_id", // Column referencing this entity
to = "genre_id" // Column referencing related entity
}
}]
)]
pub struct Book {
#[georm(id)]
pub id: i32,
pub title: String,
}
#[derive(Georm)]
#[georm(
table = "genres",
many_to_many = [{
entity = Book,
name = "books",
table = "books",
link = {
table = "book_genres",
from = "genre_id", // Note: reversed perspective
to = "book_id"
}
}]
)]
pub struct Genre {
#[georm(id)]
pub id: i32,
pub name: String,
}
```
**Generated methods**:
- `book.get_genres(pool).await? -> Vec`
- `genre.get_books(pool).await? -> Vec`
#### Relationship Attribute Reference
| Attribute | Description | Required | Default |
|--------------|------------------------------------------------------|----------|---------|
| `entity` | Target entity type | Yes | N/A |
| `name` | Method name (generates `get_{name}`) | Yes | N/A |
| `table` | Target table name | Yes | N/A |
| `remote_id` | Target table's key column | No | `"id"` |
| `nullable` | Whether relationship can be null (field-level only) | No | `false` |
| `link.table` | Join table name (many-to-many only) | Yes* | N/A |
| `link.from` | Column referencing this entity (many-to-many only) | Yes* | N/A |
| `link.to` | Column referencing target entity (many-to-many only) | Yes* | N/A |
*Required for many-to-many relationships
#### Complex Relationship Example
Here's a comprehensive example showing multiple relationship types:
```rust
#[derive(Georm)]
#[georm(
table = "posts",
one_to_many = [{
entity = Comment,
name = "comments",
table = "comments",
remote_id = "post_id"
}],
many_to_many = [{
entity = Tag,
name = "tags",
table = "tags",
link = {
table = "post_tags",
from = "post_id",
to = "tag_id"
}
}]
)]
pub struct Post {
#[georm(id)]
pub id: i32,
pub title: String,
pub content: String,
// Field-level relationship (foreign key)
#[georm(relation = {
entity = Author,
table = "authors",
name = "author"
})]
pub author_id: i32,
// Nullable field-level relationship
#[georm(relation = {
entity = Category,
table = "categories",
name = "category",
nullable = true
})]
pub category_id: Option,
}
```
**Generated methods**:
- `post.get_author(pool).await? -> Author` (from field relation)
- `post.get_category(pool).await? -> Option` (nullable field relation)
- `post.get_comments(pool).await? -> Vec` (one-to-many)
- `post.get_tags(pool).await? -> Vec` (many-to-many)
## API Reference
### Core Operations
All entities implementing `Georm` get these methods:
```rust
// Query operations
Post::find_all(pool).await?; // Find all posts
Post::find(pool, &post_id).await?; // Find by ID
// Mutation operations
post.create(pool).await?; // Insert new record
post.update(pool).await?; // Update existing record
post.create_or_update(pool).await?; // Upsert operation
post.delete(pool).await?; // Delete this record
Post::delete_by_id(pool, &post_id).await?; // Delete by ID
// Utility
post.get_id(); // Get entity ID
```
### Defaultable Operations
Entities with defaultable fields get a companion `Default` struct:
```rust
// Create with defaults
post_default.create(pool).await?;
```
## Configuration
### Attributes Reference
#### Struct-level attributes
```rust
#[georm(
table = "table_name", // Required: database table name
one_to_one = [{ /* ... */ }], // Optional: one-to-one relationships
one_to_many = [{ /* ... */ }], // Optional: one-to-many relationships
many_to_many = [{ /* ... */ }] // Optional: many-to-many relationships
)]
```
#### Field-level attributes
```rust
#[georm(id)] // Mark as primary key
#[georm(defaultable)] // Mark as defaultable field
#[georm(generated)] // Mark as generated by default field
#[georm(generated_always)] // Mark as always generated field
#[georm(relation = { /* ... */ })] // Define relationship
```
## Performance
Georm is designed for zero runtime overhead:
- **Compile-time queries**: All SQL is verified at compile time
- **No reflection**: Direct field access, no runtime introspection
- **Minimal allocations**: Efficient use of owned vs borrowed data
- **SQLx integration**: Leverages SQLx's optimized PostgreSQL driver
## Examples
### Comprehensive Example
For an example showcasing user management, comments, and follower relationships, see the example in `examples/postgres/users-comments-and-followers/`. This example demonstrates:
- User management and profile management
- Comment system with user associations
- Follower/following relationships (many-to-many)
- Interactive CLI interface with CRUD operations
- Database migrations and schema setup
To run the example:
```bash
# Set up your database
export DATABASE_URL="postgres://username:password@localhost/georm_example"
# Run migrations
cargo sqlx migrate run
# Run the example
cd examples/postgres/users-comments-and-followers
cargo run help # For a list of all available actions
```
## Comparison
| Feature | Georm | SeaORM | Diesel |
|----------------------|-------|--------|--------|
| Compile-time safety | ✅ | ✅ | ✅ |
| Relationship support | ✅ | ✅ | ✅ |
| Async support | ✅ | ✅ | ⚠️[^1] |
| Learning curve | Low | Medium | High |
| Macro simplicity | ✅ | ❌ | ❌ |
| Advanced queries | ❌ | ✅ | ✅ |
[^1]: Requires `diesel-async`
## Roadmap
### High Priority
- **Transaction Support**: Comprehensive transaction handling with atomic operations
- **Simplified Relationship Syntax**: Remove redundant table/remote_id specifications by inferring them from target entity metadata
- **Multi-Database Support**: MySQL and SQLite support with feature flags
### Medium Priority
- **Composite Key Relationships**: Add relationship support (one-to-one, one-to-many, many-to-many) for entities with composite primary keys
- **Field-Based Queries**: Generate `find_by_{field_name}` methods that return `Vec` for regular fields or `Option` for unique fields
- **Relationship Optimization**: Eager loading and N+1 query prevention
- **Automatic Table Name Inference**: Infer table names from struct names (PascalCase → snake_case plural), eliminating the need for explicit `#[georm(table = "...")]` attributes
- **Alternative Attribute Syntax**: Introduce path-based attribute syntax as sugar (e.g., `#[table("users")]`, `#[id]`) while maintaining backward compatibility
### Lower Priority
- **Migration Support**: Schema generation and evolution utilities
- **Soft Delete**: Optional soft delete with `deleted_at` timestamps
- **Enhanced Error Handling**: Custom error types with better context
## Contributing
We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.
### Development Setup
#### Prerequisites
- **Rust 1.86+**: Georm uses modern Rust features and follows the MSRV specified in `rust-toolchain.toml`
- **PostgreSQL 12+**: Required for running tests and development
- **Git**: For version control
- **Jujutsu**: For version control (alternative to Git)
#### Required Tools
The following tools are used in the development workflow:
- **[just](https://github.com/casey/just)**: Task runner for common development commands
- **[cargo-deny](https://github.com/EmbarkStudios/cargo-deny)**: License and security auditing
- **[sqlx-cli](https://github.com/launchbadge/sqlx/tree/main/sqlx-cli)**: Database migrations and management
- **[bacon](https://github.com/Canop/bacon)**: Background code checker (optional but recommended)
Install these tools:
```bash
# Install just (task runner)
cargo install just
# Install cargo-deny (for auditing)
cargo install cargo-deny
# Install sqlx-cli (for database management)
cargo install sqlx-cli --no-default-features --features native-tls,postgres
# Install bacon (optional, for live feedback)
cargo install bacon
```
#### Quick Start
```bash
# Clone the repository
git clone https://github.com/Phundrak/georm.git
cd georm
# Set up your PostgreSQL database and set DATABASE_URL
export DATABASE_URL="postgres://username:password@localhost/georm_test"
# Run migrations
just migrate
# Run all tests
just test
# Run linting
just lint
# Run security audit
just audit
# Run all checks (format, lint, audit, test)
just check-all
```
#### Available Commands (via just)
```bash
just # Default: run linting
just build # Build the project
just build-release # Build in release mode
just test # Run all tests
just lint # Run clippy linting
just audit # Run security and license audit
just migrate # Run database migrations
just format # Format all code
just format-check # Check code formatting
just check-all # Run all checks (format, lint, audit, test)
just clean # Clean build artifacts
```
#### Running Specific Tests
```bash
# Run tests for a specific module
cargo test --test simple_struct
cargo test --test defaultable_struct
cargo test --test m2m_relationship
# Run tests with output
cargo test -- --nocapture
# Run a specific test function
cargo test defaultable_struct_should_exist
```
#### Development with Bacon (Optional)
For continuous feedback during development:
```bash
# Run clippy continuously
bacon
# Run tests continuously
bacon test
# Build docs continuously
bacon doc
```
#### Devenv Development Environment (Optional)
If you use [Nix](https://nixos.org/), you can use the provided devenv configuration for a reproducible development environment:
```bash
# Enter the development shell with all tools pre-installed
devenv shell
# Or use direnv for automatic environment activation
direnv allow
```
The devenv configuration provides:
- Exact Rust version (1.86) with required components
- All development tools (just, cargo-deny, sqlx-cli, bacon)
- LSP support (rust-analyzer)
- SQL tooling (sqls for SQL language server)
- PostgreSQL database for development
**Devenv configuration:**
- **Rust toolchain**: Specified version with rustfmt, clippy, and rust-analyzer
- **Development tools**: just, cargo-deny, sqlx-cli, bacon
- **SQL tools**: sqls (SQL language server)
- **Database**: PostgreSQL with automatic setup
- **Platform support**: Cross-platform (Linux, macOS, etc.)
#### Database Setup for Tests
Tests require a PostgreSQL database. Set up a test database:
```sql
-- Connect to PostgreSQL as superuser
CREATE DATABASE georm_test;
CREATE USER georm_user WITH PASSWORD 'georm_password';
GRANT ALL PRIVILEGES ON DATABASE georm_test TO georm_user;
```
Set the environment variable:
```bash
export DATABASE_URL="postgres://georm_user:georm_password@localhost/georm_test"
```
#### IDE Setup
- Ensure `rust-analyzer` is configured
- Set up PostgreSQL connection for SQL syntax highlighting
#### Code Style
The project uses standard Rust formatting:
```bash
# Format code
just format
# Check formatting (CI)
just format-check
```
Clippy linting is enforced:
```bash
# Run linting
just lint
# Fix auto-fixable lints
cargo clippy --fix
```
## License
Licensed under either of
* MIT License ([LICENSE-MIT](LICENSE-MIT.md) or http://opensource.org/licenses/MIT)
* GNU General Public License v3.0 ([LICENSE-GPL](LICENSE-GPL.md) or https://www.gnu.org/licenses/gpl-3.0.html)
at your option.
## Acknowledgments
- Built on top of the excellent [SQLx](https://github.com/launchbadge/sqlx) library
- Inspired by [Hibernate](https://hibernate.org/)
