postgres-derive
Syntax extensions to automatically derive FromSql
and ToSql
implementations for Postgres enum,
domain, and composite types.
The generated code requires rust-postgres 0.14 or 0.15 and Rust 1.20.0 or higher.
Usage
Simply depend on the postgres-derive
crate and register it as a plugin:
Cargo.toml
# ...
[dependencies]
postgres-derive = "0.3"
postgres = "0.15"
lib.rs
#[macro_use]
extern crate postgres;
#[macro_use]
extern crate postgres_derive;
#[derive(Debug, ToSql, FromSql)]
pub enum Mood {
Sad,
Ok,
Happy,
}
// ...
Types
Enums
Postgres enums correspond to C-like enums in Rust:
CREATE TYPE "Mood" AS ENUM (
'Sad',
'Ok',
'Happy'
);
#[derive(Debug, ToSql, FromSql)]
enum Mood {
Sad,
Ok,
Happy,
}
The implementations will expect exact matches between the type names and variants. The
#[postgres(...)]
attribute can be used to adjust the names used on the Postgres side:
CREATE TYPE mood AS ENUM (
'sad',
'ok',
'happy'
);
#[derive(Debug, ToSql, FromSql)]
#[postgres(name = "mood")]
enum Mood {
#[postgres(name = "sad")]
Sad,
#[postgres(name = "ok")]
Ok,
#[postgres(name = "happy")]
Happy,
}
Domains
Postgres domains correspond to tuple structs with one member in Rust:
CREATE DOMAIN "SessionId" AS BYTEA CHECK(octet_length(VALUE) = 16);
#[derive(Debug, FromSql, ToSql)]
struct SessionId(Vec<u8>);
As above, the implementations will expect an exact match between the Rust and Postgres type names,
and the #[postgres(...)]
attribute can be used to adjust that behavior:
CREATE DOMAIN session_id AS BYTEA CHECK(octet_length(VALUE) = 16);
#[derive(Debug, FromSql, ToSql)]
#[postgres(name = "session_id")]
struct SessionId(Vec<u8>);
Composites
Postgres composite types correspond to structs in Rust:
CREATE TYPE "InventoryItem" AS (
name TEXT,
supplier_id INT,
price DOUBLE PRECISION
);
#[derive(Debug, FromSql, ToSql)]
struct InventoryItem {
name: String,
supplier_id: i32,
price: Option<f64>,
}
Again, the implementations will expect an exact match between the names of the Rust and Postgres
types and fields, which can be adjusted via the #[postgres(...)]
attribute:
CREATE TYPE inventory_item AS (
name TEXT,
supplier_id INT,
the_price DOUBLE PRECISION
);
#[derive(Debug, FromSql, ToSql)]
#[postgres(name = "inventory_item")]
struct InventoryItem {
name: String,
supplier_id: i32,
#[postgres(name = "the_price")]
price: Option<f64>,
}
License
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.