mssql-derive

Part of the rust-mssql-driver project.

Procedural macros for SQL Server row mapping and parameter handling.

Overview

This crate provides derive macros for automatically implementing row-to-struct mapping and struct-to-parameter conversion, reducing boilerplate when working with SQL Server data.

Available Macros

FromRow

Automatically implement row-to-struct conversion:

use mssql_derive::FromRow;

#[derive(FromRow)]
struct User {
    id: i32,
    #[mssql(rename = "user_name")]
    name: String,
    email: Option<String>,
}

// Usage
let user: User = row.into()?;

Field Attributes

Struct Attributes

Supported cases: snake_case, camelCase, PascalCase, SCREAMING_SNAKE_CASE

ToParams

Automatically convert structs to query parameters:

use mssql_derive::ToParams;

#[derive(ToParams)]
struct NewUser {
    name: String,
    #[mssql(rename = "email_address")]
    email: String,
    #[mssql(skip)]
    internal_id: u64,
}

let user = NewUser {
    name: "Alice".into(),
    email: "alice@example.com".into(),
    internal_id: 0,
};

client.execute(
    "INSERT INTO users (name, email_address) VALUES (@name, @email_address)",
    &user.to_params()?,
).await?;

Tvp (Table-Valued Parameters)

Create table-valued parameters for passing collections to stored procedures:

use mssql_derive::Tvp;

// First, create the table type in SQL Server:
// CREATE TYPE dbo.UserIdList AS TABLE (UserId INT NOT NULL);

#[derive(Tvp)]
#[mssql(type_name = "dbo.UserIdList")]
struct UserId {
    #[mssql(rename = "UserId")]
    user_id: i32,
}

let ids = vec![UserId { user_id: 1 }, UserId { user_id: 2 }];
let tvp = TvpValue::new(&ids)?;

client.execute(
    "SELECT * FROM users WHERE id IN (SELECT UserId FROM @ids)",
    &[&tvp],
).await?;

Complete Example

use mssql_derive::{FromRow, ToParams};

#[derive(FromRow)]
#[mssql(rename_all = "PascalCase")]
struct User {
    id: i32,
    #[mssql(rename = "UserName")]
    name: String,
    #[mssql(default)]
    email: Option<String>,
    #[mssql(skip)]
    computed: String,
}

#[derive(ToParams)]
struct UpdateUser {
    #[mssql(rename = "UserId")]
    id: i32,
    name: String,
}

// Read users
let mut stream = client.query("SELECT * FROM Users", &[]).await?;
while let Some(row) = stream.next().await {
    let user: User = row?.into()?;
    println!("{}: {}", user.id, user.name);
}

// Update user
let update = UpdateUser { id: 1, name: "Bob".into() };
client.execute(
    "UPDATE Users SET UserName = @name WHERE Id = @UserId",
    &update.to_params()?,
).await?;

Type Inference for TVPs

The macro automatically infers SQL types from Rust types:

License

MIT OR Apache-2.0