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https://github.com/mjovanc/njord

A lightweight ORM library for Rust ⛵
https://github.com/mjovanc/njord

njord njord-orm orm orm-library rust rust-library rustlang sqlite

Last synced: 21 days ago
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A lightweight ORM library for Rust ⛵

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README

        

njord

# Njord

![build](https://img.shields.io/github/actions/workflow/status/mjovanc/njord/core.yml?branch=master)
![crates.io](https://img.shields.io/crates/v/njord.svg)
[![njord: rustc 1.77.1+](https://img.shields.io/badge/njord-rustc_1.77.1+-lightgray.svg)](https://blog.rust-lang.org/2024/03/28/Rust-1.77.1.html)
[![njord_derive: rustc 1.77+](https://img.shields.io/badge/njord_derive-rustc_1.77.1+-lightgray.svg)](https://blog.rust-lang.org/2024/03/28/Rust-1.77.1.html)
[![discord](https://img.shields.io/discord/1181504958802186240.svg?style=flat&color=lightgray&logo=discord)](https://discord.gg/2uppTzjUHE)

A lightweight and extensible ORM library for Rust.

## Table of Contents
- [Supported Databases](#supported-databases)
- [Getting Started](#getting-started)
- [Initializing a new project](#initializing-a-new-project)
- [Add a schema file](#add-a-schema-file)
- [Usage](#usage)
- [SQlite](#sqlite)
- [Establish a connection](#establish-a-connection)
- [Insert data](#insert-data)
- [Update data](#update-data)
- [Delete data](#delete-data)
- [Select data](#select-data)
- [Getting Help](#getting-help)
- [Reporting Issues](#reporting-issues)
- [Contributing](#contributing)
- [Code of Conduct](#code-of-conduct)
- [Contributors](#contributors)
- [License](#license)

## Supported Databases

| Database | Support | Status |
|------------|-----------|-----------------------|
| SQLite | ✅ | Currently supported. |
| PostgreSQL | ❌ | Not supported, help us implement it? |
| MySQL | ❌ | Not supported, help us implement it? |
| MariaDB | ❌ | Not supported, help us implement it? |
| Oracle | ❌ | Not supported, help us implement it? |
| MSSQL | ❌ | Not supported, help us implement it? |

## Getting Started

### Initializing a new project

The first thing we need to do is generate our project.

```sh
cargo new --bin njord_demo
```

Now, let’s add Njord to our dependencies. We’re also going to use a tool called .env to manage our environment variables for us. We’ll add it to our dependencies as well.

```toml
[dependencies]

# The core APIs, including the Table trait.
# using #[derive(Table)] to make njord work with structs
# and enums defined in your crate.
njord = { version = "", features = ["sqlite"] }
njord_derive = { version = "" }
```

### Add a schema file

Now we are going to define our schema file that we will create under `src/schema.rs`. We will store basically our structs that will map against the database.

```rust
#[derive(Table)]
#[table_name = "users"]
pub struct User {
id: usize,
username: String,
email: String,
address: String,
}

#[derive(Table)]
#[table_name = "categories"]
pub struct Category {
id: usize,
name: String,
}

#[derive(Table)]
#[table_name = "products"]
pub struct Product {
id: usize,
name: String,
description: String,
price: f64,
stock_quantity: usize,
category: Category, // one-to-one relationship
discount: Option, // allow for null
}

#[derive(Table)]
#[table_name = "orders"]
pub struct Order {
id: usize,
user: User, // one-to-one relationship
products: Vec, // one-to-many relationship - populates from based on junction table (gets from macro attribute "table_name" and combines them for example, orders_products)
total_cost: f64,
}
```

Now that we have that in place, we need to create the SQL for setting this up in the database and execute it.

```sql
-- users table
CREATE TABLE users (
id INTEGER PRIMARY KEY,
username TEXT NOT NULL,
email TEXT NOT NULL,
address TEXT NOT NULL
);

-- products table
CREATE TABLE products (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
description TEXT NOT NULL,
price REAL NOT NULL,
stock_quantity INTEGER NOT NULL,
category INTEGER REFERENCES categories(id),
discount: REAL NULL
);

-- orders table
CREATE TABLE orders (
id INTEGER PRIMARY KEY,
user_id INTEGER REFERENCES users(id),
total_cost REAL NOT NULL
);

-- order_products table
CREATE TABLE order_products (
order_id INTEGER REFERENCES orders(id),
product_id INTEGER REFERENCES products(id),
PRIMARY KEY (order_id, product_id)
);
```

## Usage

So how can we establish a connection and actually select or insert data to our database? Let's go through it. Note that these examples might be outdated, so dont treat it as a source of truth.

### SQlite

#### Establish a connection

To establish a connection we first need to call the `sqlite::open()` function and use it with a match statement.

```rust
let db_name = "njord.db";
let db_path = Path::new(&db_name);

match sqlite::open(db_path) {
Ok(c) => {
println!("Database opened successfully!");

// Additional logic when we are connected.
// We need to open a connection and pass it
// to the corresponding sqlite function.
}
Err(err) => eprintln!("Error opening the database: {}", err),
}
```

#### Insert data

```rust
let user = User {
username: String::from("john_doe"),
email: String::from("[email protected]"),
address: String::from("123 Main St"),
};

let result = sqlite::insert(c, vec![user]);
assert!(result.is_ok());
```

**Generated SQL**

```sql
INSERT INTO users (
username,
email,
address
) VALUES (
'john_doe',
'[email protected]',
'123 Main St'
)
```

#### Update data

```rust
let columns = vec!["username".to_string(), "address".to_string()];
let where_condition = Condition::Eq("username".to_string(), "john_doe".to_string());

let user = User {
username: String::from("john_doe_2"),
email: String::from("[email protected]"),
address: String::from("1234 Main St"),
};

let mut order = HashMap::new();
order.insert(vec!["id".to_string()], "DESC".to_string());

let result = sqlite::update(c, user)
.set(columns)
.where_clause(where_condition)
.order_by(order)
.limit(4)
.offset(0)
.build();

assert!(result.is_ok());
```

**Generated SQL**

```sql
UPDATE users
SET
username
WHERE
username = 'john_doe'
ORDER BY
id DESC
LIMIT 4
OFFSET 0

```

#### Delete data

```rust
let where_condition = Condition::Eq("username".to_string(), "john_doe".to_string());

let mut order = HashMap::new();
order.insert(vec!["id".to_string()], "DESC".to_string());

let result = sqlite::delete(c)
.from(User::default())
.where_clause(where_condition)
.order_by(order)
.limit(20)
.offset(0)
.build();

assert!(result.is_ok());
```

**Generated SQL**

```sql
DELETE FROM users
WHERE
username = 'john_doe'
ORDER BY
id DESC
LIMIT 20
OFFSET 0
```

#### Select data

```rust
let columns = vec!["id".to_string(), "username".to_string(), "email".to_string(), "address".to_string()];
let where_condition = Condition::Eq("username".to_string(), "john_doe".to_string());
let group_by = vec!["username".to_string(), "address".to_string()];

let mut order_by = HashMap::new();
order_by.insert(vec!["id".to_string()], "ASC".to_string());

let having_condition = Condition::Gt("id".to_string(), "1".to_string());

// Build the query
// We need to pass the struct User with the Default trait in .from()
let result: Result> = sqlite::select(c, columns)
.from(User::default())
.where_clause(where_condition)
.order_by(order_by)
.group_by(group_by)
.having(having_condition)
.build();

match result {
Ok(result) => {
assert_eq!(result.len(), 1);
}
Err(error) => panic!("Failed to SELECT: {:?}", error),
};
```

**Generated SQL**

```sql
SELECT
id,
username,
email,
address
FROM
users
WHERE
username = 'mjovanc'
GROUP BY
username,
email
HAVING
id > 1
ORDER BY
email DESC
```

## Getting Help

Are you having trouble with Njord? We want to help!

- Read through the documentation on our [docs](https://docs.rs/njord/latest/njord/).

- If you are upgrading, read the release notes for upgrade instructions and "new and noteworthy" features.

- Ask a question we monitor stackoverflow.com for questions tagged with Njord.

- Report bugs with Njord at https://github.com/mjovanc/njord/issues.

## Reporting Issues

Njord uses GitHub’s integrated issue tracking system to record bugs and feature requests. If you want to raise an issue, please follow the recommendations below:

- Before you log a bug, please search the issue tracker to see if someone has already reported the problem.

- If the issue doesn’t already exist, create a new issue.

- Please provide as much information as possible with the issue report. We like to know the Njord version, operating system, and Rust version version you’re using.

- If you need to paste code or include a stack trace, use Markdown. ``` escapes before and after your text.

- If possible, try to create a test case or project that replicates the problem and attach it to the issue.

## Contributing

Before contributing, please read the [contribution](https://github.com/mjovanc/njord/blob/master/CONTRIBUTING.md) guide for useful information how to get started with Njord as well as what should be included when submitting a contribution to the project.

## Code of Conduct

Anyone who interacts with Njord in any space, including but not limited to this GitHub repository, must follow our code of conduct.

## Contributors

The following contributors have either helped to start this project, have contributed
code, are actively maintaining it (including documentation), or in other ways
being awesome contributors to this project. **We'd like to take a moment to recognize them.**

[mjovanc](https://github.com/mjovanc)
[appelskrutt34](https://github.com/appelskrutt34)
[](https://github.com/ahsentekd)
[](https://github.com/chinmer)
[SvMak](https://github.com/SvMak)

## License

The BSD 3-Clause License.