SQG v0.10.0: Java Streams & List Type Support

Mar 5, 2026

SQG is a type-safe SQL code generator — you write .sql files with annotated queries, and it generates strongly-typed database access code for TypeScript and Java by introspecting your queries against real database engines at build time.

Here’s what’s new in v0.10.0.

Java: Stream-based result methods

Generated Java code now includes methods that return Stream<T> in addition to List<T>. This gives you lazy evaluation, easier composition with the standard library, and avoids materializing large result sets into memory when you don’t need to.

try (Stream<User> users = queries.getAllUsersStream()) {
    users.forEach(user -> process(user));
}

The stream holds a reference to the underlying ResultSet, so it needs to be closed after use — hence the try-with-resources.

Java: Better array/list field support

Array columns like TEXT[] or INTEGER[] are now handled correctly in generated Java code. Previously these types could produce incorrect mappings — they now resolve to proper List<String>, List<Integer>, etc.

DuckDB: List types in Appender

The DuckDB appender now supports list/array column types. If your table has a column like tags VARCHAR[], the generated appender method accepts the corresponding list type and writes it correctly using DuckDB’s bulk insert API.

Upgrade with npm install -g @sqg/[email protected] or update your project’s dependency. Full source on GitHub. Try it out in the playground.