README.md

# Cake SQL Query Builder for Gleam

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<br>
<br>

<p align="center">
  <img src="https://raw.githubusercontent.com/inoas/gleam-cake/main/cake-logo.png" alt="Cake Logo" style="max-height: 33vh; width: auto; height: auto" width="480" height="480"/>
</p>

<br>

<p align="center">
  <i>
    🎂Cake is a library written in Gleam to compose SQL queries targeting SQL
    dialects 🐘PostgreSQL, 🪶SQLite, 🦭MariaDB and 🐬MySQL.
  </i>
</p>

<br>
<br>

## Installation

```shell
gleam add cake@v2
```

Further documentation can be found on [hexdocs.pm/cake](https://hexdocs.pm/cake).

### Adapters

- 🐘PostgreSQL on Erlang: [hex.pm/packages/cake_pog](https://hex.pm/packages/cake_pog)
- 🪶SQLite on Erlang: [hex.pm/packages/cake_sqlight](https://hex.pm/packages/cake_sqlight)
- 🦭MariaDB and 🐬MySQL on Erlang: [hex.pm/packages/cake_gmysql](https://hex.pm/packages/cake_gmysql)

<!--
TODO:
- SQLite on WASM/JS https://sqlite.org/wasm
- Postgres WASM via https://pglite.dev/
-->

## Usage

### Demos

See [docs/demo-apps/README.md](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/README.md#available-demos).

#### Code examples (from the demos)

- [cake\_demo\_select\_and\_decode.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/01_select_and_decode/src/cake_demo_select_and_decode.gleam)
- [cake\_demo\_union\_and\_decode.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/02_union_and_decode/src/cake_demo_union_and_decode.gleam)
- [cake\_demo\_insert.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/03_insert/src/cake_demo_insert.gleam)
- [cake\_demo\_delete.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/04_delete/src/cake_demo_delete.gleam)
- [cake\_demo\_update.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/05_update/src/cake_demo_update.gleam)
- [cake\_demo\_insert\_on\_conflict\_update.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/06_insert_on_conflict_update/src/cake_demo_insert_on_conflict_update.gleam)
- [cake\_demo\_select\_join.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/07_select_join/src/cake_demo_select_join.gleam)
- [cake\_demo\_prepared\_fragment.gleam](https://github.com/inoas/gleam-cake/blob/main/docs/demo-apps/demos/08_prepared_fragment/src/cake_demo_prepared_fragment.gleam)
<!--
- transactions -- TODO v2
- create view -- TODO v3
-->

### Unit tests as examples

See Cake's [tests](https://github.com/inoas/gleam-cake/tree/main/test/cake_test),
especially the _Setup_ sections in each test module.

You may also compare the tests with the
[snapshots](https://github.com/inoas/gleam-cake/tree/main/birdie_snapshots)
results.

### Intended aliases

Use the following aliases to make the library more ergonomic:

```gleam
import cake/select as s // SELECT statements
import cake/where as w // WHERE clauses
import cake/join as j // JOIN clauses
import cake/update as u // UPDATE statements
import cake/insert as i // INSERT statements
import cake/delete as d // DELETE statements
import cake/combined as c // For combined queries such as UNION
import cake/fragment as f // For arbitrary SQL code including functions
```

## Library Design

### Scope

This is an SQL query building library, thus it is not concerned about executing
queries or decoding return values from queries, but merely about being a
flexible and powerful tool to compose and craft SQL read and write queries.

#### Goals

- High degree of flexibility to compose queries:
  While the focus is on building queries there is also support for replacing
  or removing parts of queries.
- General support on these 4 large RDMS: 🐘PostgreSQL, 🪶SQLite, 🦭MariaDB and
  🐬MySQL.
- Not being tied to any specific dialect or dialect adapter library.
- Documentation should be comprehensive.
- It should be easy to use with existing gleam dialect adapters such as:
  - [pog](https://hex.pm/packages/pog)
  - [sqlight](https://hex.pm/packages/sqlight)
  - [gmysql](https://hex.pm/packages/gmysql)
- Allow to define custom SQL fragments while still being safe
  from SQL injections by using prepared statements.

#### Non-goals

- Prohibition of invalid SQL queries: You can still craft invalid queries at
  any time, for example:
  - Omitting certain parts of queries required for them to run, such as
    not specifying a table name
  - Comparing values incompatible by SQL type
- Backporting many features between different RDMBS. For example, while Cake
  supports `RETURNING` on 🐘PostgreSQL and 🪶SQLite, it does not support it on
  🦭MariaDB or 🐬MySQL.
- No automagic optimization: This library is not here to replace SQL knowledge,
  but to allow crafting and combining SQL queries in a flexible and type safe
  way. It might however work as a gateway to obtain SQL knowlege because
  the typed builder functions help to some degree in understanding how SQL
  queries can be crafted.

### Tested targets

- Sqlite3 as part of [ubuntu:latest (Docker)](https://hub.docker.com/_/ubuntu)
- [postgres:latest (Docker)](https://hub.docker.com/_/postgres)
- [mariadb:latest (Docker)](https://hub.docker.com/_/mariadb)
- [mysql:latest (Docker)](https://hub.docker.com/_/mysql)

The tests run on Erlang but are generally target agnostic.

While the primary use case is to run queries on servers, this library runs on
any Gleam target and for example in conjunction with following adapters, you may
run queries composed with this library in browsers:
- [sqlite3 WASM/JS](https://sqlite.org/wasm)
- [PGLite (Postgres WASM)](https://pglite.dev/)

## Development

### Run test suite locally

```shell
bin/docker/attached
# wait a few seconds until everything is ready
# if you run gleam test too early, it will crash
gleam test
```

### Helper commands

```shell
bin/docker/attached
bin/docker/detached
bin/docker/down

bin/test

bin/birdie/interactive-review
bin/birdie/accept-all
bin/birdie/reject-all
```

## Library naming

The best part of working with CakePHP 3+ used to be its Query Builder. This
library is inspired by that and thus the name.

Thank you [@lorenzo](https://github.com/lorenzo) and
[@markstory](https://github.com/markstory) for creating and maintaining CakePHP
and its awesome query builder over the years.