Crate diesel_ease 

Diesel Ease

A proc macro that will generate some useful of functions for database operations that uses diesel.

This crate is for those who are using diesel for database operations and want to have less boilerplate code.

This crate will generate functions based on your struct and fields of that struct.

You can open your crate’s docs to see the generated functions. Run cargo doc --open to see the docs.

Installation

[dependencies]
diesel_ease = "0.1"

Usage

Lets assume you have two structs named User and NewUser in your src/models.rs file:

#[derive(Insertable)]
#[table_name = "users"]
pub struct NewUser {
    pub name: String,
}

#[diesel_ease(PgConnection)] // here we used the macro
#[derive(Queryable, Clone, Debug, PartialEq)]
pub struct User {
    pub id: i32,
    pub name: String,
}

Lets also assume that you have table named users in your database and also in your src/schema.rs file:

table! {
    users (id) {
        id -> Int4,
        name -> Varchar,
    }
}

Now you will get these associated functions by using diesel_ease proc macro:

• delete_by_id
• delete_by_name
• get_by_id
• get_by_name
• insert
• get_ids_by_name
• get_names_by_id
• update_ids_by_name
• update_names_by_id
• get_all
• delete_all

NOTE: How many functions will you get and which functions will you get is based on your struct

You can use these methods like so:

// connection to your database
let connection = establish_connection();

// get the names of the User whose id is 18
let name: String = User::get_names_by_id(&connection, 18).unwrap()[0].clone();

// update the name of the user whose id is 18
let updated_name: String = User::update_names_by_id(&connection, 18, format!("{}-2", name))
    .unwrap()
    .name;

assert_ne!(name, updated_name);

// delete the user whose id is 18
User::delete_by_id(&connection, 18).unwrap();

// Now again get the names of the User whose id is 18
let name: Vec<String> = User::get_names_by_id(&connection, 18).unwrap();

assert_eq!(name.len(), 0);

// insert a new user
let new_user = NewUser {
    name: "Mostofa".to_string(),
};

let inserted_user: User = User::insert(&connection, new_user).unwrap();

assert_eq!(&inserted_user.name, "Mostofa");

Some important notes

• Your schema must be the name of your model/struct.

  It must be in lowercase. and there must be s at the end.

  For example if you have struct User in src/models.rs, so you must have users in your src/schema.rs file.

• Your model must be in crate::models and your schema must be in crate::schema.

  For example your struct could be crate::models::User, so your schema must be crate::schema::users

• There must be a struct New{Model}for the model for inserting values.

  For example if you have struct User in src/models.rs, then you must have struct NewUser in src/models.rs.

• You need to pass the database connection struct to the macro. It can be one of these

  • diesel::mysql::MysqlConnection
  • diesel::pg::PgConnection
  • diesel::sqlite::SqliteConnection

  Whatever you pass to the macro, you need to import this in src/models.rs file.

• You cannot use references in your struct. For example the struct

    struct User<'a> {
        id: i32,
        name: &'a str,
    }

  will not work

Attribute Macros

diesel_ease

A macro to generate useful associated functions for database operations for the given struct.