pg-worm

PostgreSQL's Worst ORM

pg-worm is a straightforward, fully typed, async ORM and Query Builder for PostgreSQL. Well, at least that's the goal.

Features/Why pg-worm?

• Existing ORMs are not async, require you to write migrations or use a cli. pg-worm's explicit goal is to be easy and to require no setup beyond defining your types.

• pg-worm also features built-in pooling and a concise syntax.

• pg-worm doesn't get in your way - easily include raw queries while still profiting off the other features.

Usage

This library is based on tokio_postgres and is intended to be used with tokio.

Fortunately, using pg-worm is very easy.

Simply derive the Model trait for your type, connect to your database and you are ready to go!

Here's a quick example:

// Import the prelude to get started quickly
use pg_worm::prelude::*;

#[derive(Model)]
struct Book {
    // An auto-generated primary key
    #[column(primary_key, auto)]
    id: i64,
    title: String,
    author_id: i64
}

#[derive(Model)]
struct Author {
    #[column(primary_key, auto)]
    id: i64,
    name: String
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // First create a connection. This can be only done once.
    Connection::build("postgres://postgres:postgres@localhost:5432").connect()?;

    // Then, create tables for your models. 
    // Use `try_create_table!` if you want to fail if a
    // table with the same name already exists.
    //
    // `force_create_table` drops the old table,
    // which is useful for development.
    //
    // If your tables already exist, skip this part.
    force_create_table!(Author, Book).await?;

    // Next, insert some data.
    // This works by passing values for all
    // fields which aren't autogenerated.
    Author::insert("Stephen King").await?;
    Author::insert("Martin Luther King").await?;
    Author::insert("Karl Marx").await?;
    Book::insert("Foo - Part I", 1).await?;
    Book::insert("Foo - Part II", 2).await?;
    Book::insert("Foo - Part III", 3).await?;

    // Let's start with a simple query for all books:
    let books = Book::select().await?; // Vec<Book>
    assert_eq!(books.len(), 3);

    // You can also search for a specific book.
    // Adding a `WHERE` clause is as simple as
    // calling a method on the respective field:
    let book = Book::select_one()
        .where_(Book::title.eq(&"Foo - Part I".to_string()))
        .await?; // Option<Book>
    assert!(book.is_some());

    // Or update exsisting records:
    let books_updated = Book::update()
        .set(Book::title, &"Foo - Part III".to_string())
        .where_(Book::title.eq(&"Foo - Part II".to_string()))
        .await?; // u64
    assert_eq!(books_updated, 1);

    // Or delete a book, you don't like:
    let books_deleted = Book::delete()
        .where_(Book::title.eq(&"Foo - Part III".to_string()))
        .await?; // u64
    assert_eq!(books_deleted, 2);

    Ok(())
}

If you want to see more code examples, have a look at the tests directory.

Query Builders

As you can see above, pg-worm allows you to build queries by chaining methods on so called 'builders'. For each query type pg-worm provides a respective builder (except for INSERT which is handled differently).

These builders expose a set of methods for building queries. Here's a list of them:

Filtering using WHERE

.where_() can be used to easily include WHERE clauses in your queries.

This is done by passing a Where object which can be constructed by calling methods on the respective column. pg-worm automatically constructs a constant for each field of your Model.

A practical example would look like this:

let where_: Where<'_> = MyModel::my_field.eq(&5);

Available methods

Currently, the following methods are implemented:

Boolean logic

You can also chain/modify these filters with standard boolean logic:

Book::select()
    .where_(!Book::id.eq(&1) & Book::id.gt(&3))
    .await?;

Executing a query

After having finished building your query, you can simply call .await. This will turn the builder into a Query object which is then executed asynchronously.

Executing a query will always result in a Result.

Raw queries

Though these features are nice, they are not sufficient for all applications. This is why you can easily execute custom queries and still take advantage of automatic parsing, etc:

// NOTE: You have to pass the exact type that PostgreSQL is 
// expecting. Doing otherwise will result in a runtime error.
let king_books = Book::query(r#"
        SELECT * FROM book 
        JOIN author ON author.id = book.author_id
        WHERE POSITION(? in author.name) > 0 
    "#, 
    vec![&"King".to_string()]
).await?;
assert_eq!(king_books.len(), 2);

Alse see .where_raw on query builders by which you can pass a raw condition without needing to write the whole query yourself.

Transactions

pg-worm also supports transactions. You can easily execute any query inside a Transaction and only commit when you are satisfied.

Transactions are automatically rolled-back when dropped, unless they have been committed beforehand.

Here's an example:

use pg_worm::prelude::*;

#[derive(Model)]
struct Foo {
    bar: i64
}

async fn foo() -> Result<(), Box<dyn std::error::Error>> {
    // Easily create a new transaction
    let transaction = Transaction::begin().await?;

    // Execute any query inside the transaction
    let all_foo = transaction.execute(
        Foo::select()
    ).await?;   

    // Commit the transaction when done.
    // If not committed, transaction are rolled back
    // when dropped.
    transaction.commit().await?;
}

Supported types

The following is a list of supported (Rust) types and which PostgreSQL type they are mapped to.

*T must be another supported type. Nesting and mixing Option/Vec is currently not supported.

JSON, timestamps and more

are supported, too. To use them activate the respective feature, like so:

# Cargo.toml
[dependencies]
pg-worm = { version = "latest-version", features = ["foo"] }

Here is a list of the supported features/types with their respective PostgreSQL type:

• "serde-json" for serde_json v1.0

  Rust type	PostgreSQL type
  Value	JSONB

• "time" for time v3.0

  Rust type	PostgreSQL type
  Date	DATE
  Time	TIME
  PrimitiveDateTime	TIMESTAMP
  OffsetDateTime	TIMESTAMP WITH TIME ZONE

• "uuid" for uuid v1.0

  Rust type	PostgreSQL type
  Uuid	UUID

derive options

You can configure some options for you Model. This is done by using one of the two attributes pg-worm exposes.

The #[table] attribute

The #[table] attribute can be used to pass configurations to a Model which affect the respective table itself.

use pg_worm::prelude::*;

#[derive(Model)]
#[table(table_name = "book_list")]
struct Book {
    id: i64
}

The #[column] attribute

The #[column] attribute can be used to pass configurations to a Model's field which affect the respective column.

use pg_worm::prelude::*;

#[derive(Model)]
struct Book {
    #[column(primary_key, auto)]
    id: i64
}

MSRV

The minimum supported rust version is 1.70 as this crate uses the recently introduced OnceLock from the standard library.

License

This project is dual-licensed under the MIT and Apache 2.0 licenses.