facet-psql-schema

Bridge library for generating SeaQuery table definitions from Facet shapes.

This crate allows you to automatically generate PostgreSQL database schemas (via sea-query::Table) directly from your Rust struct definitions, leveraging facet's compile-time reflection capabilities.

Usage

Basic Conversion

Derive Facet on your structs, then convert the shape to a sea_query::Table.

use facet::Facet;
use facet_psql_schema::PartialSchema;
// Table is still available if you need to manipulate it manually
// use facet_psql_schema::Table;

#[derive(Facet)]
struct User {
    id: u64,
    username: String,
    is_active: bool,
}

fn main() {
    let shape = User::SHAPE;
    // Step 1: Convert Shape to PartialSchema
    let schema = PartialSchema::try_from(shape).expect("Schema conversion failed");
    
    // Step 2: Access the generated table(s)
    let table = schema.tables.first().expect("Expected at least one table");
    
    // table.name == "user"
    // table.columns include "id" (BigInt), "username" (Text), "is_active" (Boolean)
}

Primary Keys

Use the #[facet(...)] attribute to mark fields as primary keys.

#[derive(Facet)]
struct BlogPost {
    #[facet(psql::primary_key)]
    id: String, // Maps to Text Primary Key
    title: String,
}

Supported Types

Rust Type	PostgreSQL Type (SeaQuery)	Notes
bool	Boolean
i8, u8, i16, u16	SmallInt
i32, u32	Integer
i64, u64, usize	BigInt
f32	Real
f64	DoublePrecision
String, &str	Text	References are supported
char	Char(1)
Vec<T>	Jsonb	Currently maps to JSONB, not Array
HashMap<K,V>	Jsonb
Nested Structs	Jsonb
Enums	Integer	Field-level enums maps to Integer
Option<T>	Nullable	Wraps the inner type

Limitations

• Generics: Generic structs (struct Foo<T>) work only when monomorphized (e.g., Foo::<u64>::SHAPE).
• Fixed-Size Arrays: [T; N] are currently not supported/mapped.
• Enums: Top-level enums cannot be converted to Tables. Field-level enums map to Integer.