Examples en

Real-World Examples

Practical examples for common use cases.

User Management

Classic user entity with authentication fields:

use entity_derive::Entity;
use uuid::Uuid;
use chrono::{DateTime, Utc};

#[derive(Entity)]
#[entity(table = "users", schema = "auth")]
pub struct User {
    #[id]
    pub id: Uuid,

    #[field(create, update, response)]
    pub username: String,

    #[field(create, update, response)]
    pub email: String,

    #[field(create, update)]  // Accept but never return
    pub password_hash: String,

    #[field(response)]
    pub email_verified: bool,

    #[field(update, response)]
    pub avatar_url: Option<String>,

    #[field(response)]
    pub role: String,

    #[field(skip)]  // Internal audit field
    pub last_login_ip: Option<String>,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,

    #[auto]
    #[field(response)]
    pub updated_at: DateTime<Utc>,
}

Usage:

// Create user
let request = CreateUserRequest {
    username: "john_doe".into(),
    email: "john@example.com".into(),
    password_hash: hash_password("secret123"),
};
let user = pool.create(request).await?;

// Update user
let update = UpdateUserRequest {
    avatar_url: Some(Some("https://cdn.example.com/avatar.jpg".into())),
    ..Default::default()
};
let user = pool.update(user.id, update).await?;

// Response is safe - no password_hash, no last_login_ip
let response = UserResponse::from(&user);

Blog System

Posts with author relationship:

#[derive(Entity)]
#[entity(table = "posts", schema = "blog")]
pub struct Post {
    #[id]
    pub id: Uuid,

    #[field(create, update, response)]
    pub title: String,

    #[field(create, update, response)]
    pub slug: String,

    #[field(create, update, response)]
    pub content: String,

    #[field(create, update, response)]
    pub excerpt: Option<String>,

    #[field(create, response)]  // Set once, can't change author
    pub author_id: Uuid,

    #[field(update, response)]
    pub published: bool,

    #[field(update, response)]
    pub published_at: Option<DateTime<Utc>>,

    #[field(response)]  // Read-only, managed by triggers
    pub view_count: i64,

    #[field(skip)]  // Internal moderation
    pub moderation_status: String,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,

    #[auto]
    #[field(response)]
    pub updated_at: DateTime<Utc>,
}

Categories with many-to-many:

#[derive(Entity)]
#[entity(table = "categories", schema = "blog")]
pub struct Category {
    #[id]
    pub id: Uuid,

    #[field(create, update, response)]
    pub name: String,

    #[field(create, update, response)]
    pub slug: String,

    #[field(create, update, response)]
    pub description: Option<String>,

    #[field(response)]
    pub post_count: i64,  // Computed field

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,
}

E-Commerce

Product catalog:

#[derive(Entity)]
#[entity(table = "products", schema = "catalog")]
pub struct Product {
    #[id]
    pub id: Uuid,

    #[field(create, update, response)]
    pub name: String,

    #[field(create, update, response)]
    pub sku: String,

    #[field(create, update, response)]
    pub description: Option<String>,

    #[field(create, update, response)]
    pub price_cents: i64,

    #[field(create, update, response)]
    pub currency: String,

    #[field(update, response)]
    pub stock_quantity: i32,

    #[field(update, response)]
    pub is_active: bool,

    #[field(create, response)]
    pub category_id: Uuid,

    #[field(skip)]  // Internal cost tracking
    pub cost_cents: i64,

    #[field(skip)]  // Supplier info
    pub supplier_id: Option<Uuid>,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,

    #[auto]
    #[field(response)]
    pub updated_at: DateTime<Utc>,
}

Orders with status tracking:

#[derive(Entity)]
#[entity(table = "orders", schema = "sales")]
pub struct Order {
    #[id]
    pub id: Uuid,

    #[field(create, response)]
    pub customer_id: Uuid,

    #[field(response)]
    pub order_number: String,  // Generated by DB sequence

    #[field(update, response)]
    pub status: String,

    #[field(create, response)]
    pub total_cents: i64,

    #[field(create, response)]
    pub currency: String,

    #[field(create, update, response)]
    pub shipping_address: String,

    #[field(update, response)]
    pub tracking_number: Option<String>,

    #[field(skip)]  // Payment processor data
    pub payment_intent_id: Option<String>,

    #[field(skip)]  // Internal notes
    pub admin_notes: Option<String>,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,

    #[auto]
    #[field(response)]
    pub updated_at: DateTime<Utc>,
}

Multi-Tenant SaaS

Organization-scoped entities:

#[derive(Entity)]
#[entity(table = "organizations", schema = "tenants")]
pub struct Organization {
    #[id]
    pub id: Uuid,

    #[field(create, update, response)]
    pub name: String,

    #[field(create, response)]
    pub slug: String,  // Immutable after creation

    #[field(update, response)]
    pub plan: String,

    #[field(response)]
    pub member_count: i32,

    #[field(skip)]  // Billing info
    pub stripe_customer_id: Option<String>,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,
}

#[derive(Entity)]
#[entity(table = "projects", schema = "tenants")]
pub struct Project {
    #[id]
    pub id: Uuid,

    #[field(create, response)]  // Set once
    pub organization_id: Uuid,

    #[field(create, update, response)]
    pub name: String,

    #[field(create, update, response)]
    pub description: Option<String>,

    #[field(update, response)]
    pub archived: bool,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,

    #[auto]
    #[field(response)]
    pub updated_at: DateTime<Utc>,
}

DTOs Only (No Database)

For API contracts without persistence:

#[derive(Entity)]
#[entity(table = "webhooks", sql = "none")]
pub struct WebhookPayload {
    #[id]
    pub id: Uuid,

    #[field(create, response)]
    pub event_type: String,

    #[field(create, response)]
    pub payload: String,

    #[field(create, response)]
    pub timestamp: DateTime<Utc>,

    #[field(response)]
    pub signature: String,
}

This generates only:

• CreateWebhookPayloadRequest
• WebhookPayloadResponse
• From implementations

No repository, no SQL, no Row/Insertable structs.

Custom Queries Only

When standard CRUD isn't enough:

#[derive(Entity)]
#[entity(table = "analytics_events", schema = "analytics", sql = "trait")]
pub struct AnalyticsEvent {
    #[id]
    pub id: Uuid,

    #[field(create, response)]
    pub event_name: String,

    #[field(create, response)]
    pub user_id: Option<Uuid>,

    #[field(create, response)]
    pub properties: serde_json::Value,

    #[auto]
    #[field(response)]
    pub created_at: DateTime<Utc>,
}

// Implement custom queries yourself:
impl AnalyticsEventRepository for PgPool {
    type Error = sqlx::Error;

    async fn create(&self, dto: CreateAnalyticsEventRequest) -> Result<AnalyticsEvent, Self::Error> {
        // Batch insert, partitioned tables, etc.
    }

    async fn find_by_id(&self, id: Uuid) -> Result<Option<AnalyticsEvent>, Self::Error> {
        // Query with time-based partitioning
    }

    // Custom methods beyond CRUD:
    async fn aggregate_by_event(&self, start: DateTime<Utc>, end: DateTime<Utc>)
        -> Result<Vec<EventAggregate>, Self::Error> {
        // Complex aggregation query
    }
}