Troy is an open source macro-based Cassandra driver, similar to Slick and Quill, provides type-safe & compile-time checking for database queries. Nevertheless, it doesn’t impose a DSL to express the queries in Scala. Instead, it allows developers to write plain Cassandra-query-language (CQL) queries within Scala code, complete with schema validation. In addition, it provides cross-validation against the previous versions, ensuring safe and smooth schema migrations.
It is worth noting that Troy doesn’t connect to Cassandra during compilation. Instead, the schema is provided as CQL scripts, checked-in within same code base, consisting of plain CREATE TABLE CQL statements. That get’s loaded at compile-time into a light-weight Schema engine capable of analysing queries and providing information about column types. Those CQL scripts can be written as increments, by adding new scripts containing ALTER TABLE statement, instead of editing existing scripts. This allows Troy to check backwards and forward compatibility of queries against different versions of the schema. As well as providing tools to write migration scripts.
Currently, Troy uses reflection-based black-box macros. But also has a working proof-of-concept using the new style inline/meta as well.