Cake SQL Query Builder for Gleam

Cake is a library written in Gleam to compose SQL queries targeting SQL dialects PostgreSQL, SQLite, MariaDB and MySQL.

Installation

gleam add cake

Further documentation can be found on hexdocs.pm/cake.

Usage

Demos

See docs/demo-apps/README.md.

Code examples (from the demos)

• cake_demo_select_and_decode.gleam
• cake_demo_union_and_decode.gleam
• cake_demo_insert.gleam
• cake_demo_delete.gleam
• cake_demo_update.gleam
• cake_demo_insert_on_conflict_update.gleam
• cake_demo_select_join.gleam
• cake_demo_prepared_fragment.gleam

Unit tests as examples

See Cake’s tests, especially the Setup sections in each test module.

You may also compare the tests with the snapshots results.

Intended aliases

Use the following aliases to make the library more ergonomic:

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:
  • gleam_pgo
  • sqlight
  • 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)
• postgres:latest (Docker)
• mariadb:latest (Docker)
• mysql:latest (Docker)

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 sqlite3 WASM/JS you may run queries composed with this library in browsers.

Development

Run test suite locally

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

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 and @markstory for creating and maintaining CakePHP and its awesome query builder over the years.