Models

Models are the foundation of your Prax schema, representing database tables and their structure.

What is a Model?

A model defines a database table and its columns. Each model generates type-safe Rust code including the struct definition, query builders, and filter functions. Models are the core building block of your Prax schema.

Model Anatomy

Understanding the structure of a model definition:

Field Attributes (@)

  • • @id - Primary key
  • • @auto - Auto-increment
  • • @unique - Unique constraint
  • • @default() - Default value
  • • @map() - Column name mapping
  • • @relation() - Define relations

Model Attributes (@@)

  • • @@map() - Table name mapping
  • • @@id([]) - Composite primary key
  • • @@unique([]) - Composite unique
  • • @@index([]) - Create index
  • • @@schema() - Database schema

Complete Model Example

Here's a production-ready User model showcasing common patterns:

Composite Primary Keys

Use @@id([fields]) to define composite primary keys. This is common for join tables and multi-tenant schemas.

Indexes

Indexes improve query performance. Prax supports various index types depending on your database.

Index Type Use Case Databases
B-Tree Default, range queries, sorting All
Hash Equality comparisons only PostgreSQL, MySQL
GIN Arrays, JSONB, full-text search PostgreSQL
GiST Geometric data, full-text search PostgreSQL
BRIN Large tables with sorted data PostgreSQL

Soft Delete Pattern

Soft deletes preserve data by marking records as deleted instead of physically removing them. Use a nullable deletedAt timestamp field.

Multi-Tenant Models

Prax supports various multi-tenancy patterns for SaaS applications:

Tip: Row-level tenancy is the simplest to implement. Use Prax's built-in tenant middleware for automatic filtering. See the Middleware documentation for details.

Documenting Models

Use triple-slash comments (///) to document your models and fields. Documentation is preserved in generated code and API schemas.

Naming Conventions

Models

Use singular PascalCase. The generated table name will be lowercase plural (unless overridden with @@map).

Fields

Use camelCase for field names. Use @map() for snake_case column names if needed.

Foreign Keys

Use modelId pattern (e.g., userId, postId).

Generated Rust Code

Models generate type-safe Rust structs and query builder modules:

Model Attributes Reference

Attribute Description Example
@@map("name") Custom table name in database @@map("app_users")
@@id([fields]) Composite primary key @@id([tenantId, id])
@@unique([fields]) Composite unique constraint @@unique([email, tenantId])
@@index([fields]) Create index on fields @@index([status, createdAt])
@@schema("name") Database schema (PostgreSQL) @@schema("analytics")
@@ignore Exclude from client generation @@ignore