Exposed is an SQL library for Kotlin with DSL and DAO APIs for database interactions. While it comes with support for standard SQL data types, you can extend its functionality by creating custom column types.

Custom column types are useful when Exposed lacks support for specific database types (like PostgreSQL's enum, inet or ltree) or when you want to map columns to domain-specific types that better align with your business logic. By implementing custom columns, you gain control over data storage and retrieval while maintaining type safety.

In this article, we'll explore how to create custom column types in Exposed by creating a simple column type for PostgreSQL's enum.

Exposed: Custom column types