Skip to main content
Version: ZIO 2.x

What is Quill?

Quill provides a Quoted Domain Specific Language (QDSL) to express queries in Scala and execute them in a target language. The library's core is designed to support multiple target languages, currently featuring specializations for Structured Query Language (SQL) and Cassandra Query Language (CQL).

Scala 3 Support

ProtoQuill provides Scala 3 support for Quill rebuilding on top of new metaprogramming capabilities from the ground > up! It is published to maven-central as the quill-<module>_3 line of artifacts.

Doobie Support

See here for Doobie integration instructions.

example

  1. Boilerplate-free mapping: The database schema is mapped using simple case classes.
  2. Quoted DSL: Queries are defined inside a quote block. Quill parses each quoted block of code (quotation) at compile time and translates them to an internal Abstract Syntax Tree (AST)
  3. Compile-time query generation: The ctx.run call reads the quotation's AST and translates it to the target language at compile time, emitting the query string as a compilation message. As the query string is known at compile time, the runtime overhead is very low and similar to using the database driver directly.
  4. Compile-time query validation: If configured, the query is verified against the database at compile time and the compilation fails if it is not valid. The query validation does not alter the database state.

Note: The GIF example uses Eclipse, which shows compilation messages to the user.