Exposed

Exposed is the SQL framework used by every Arda backend service for PostgreSQL persistence. It is chosen for its idiomatic Kotlin DSL, type safety, and explicit transaction scoping — properties that align with Arda’s bitemporal persistence model and AppError contract.

• Version: 0.60.0.
• Database: PostgreSQL (production); ContainerizedPostgres test fixture for unit/integration tests.
• Repositories: operations/, accounts-component/, common-module/ (shared Table definitions and converters).

Conventions in this codebase

• DAO layer is not used. Exposed’s “DSL” API is the only API in use. Per-table Table objects describe schema; queries use select, insert, update against those.
• Transactions are explicit. Every database access is wrapped in a transaction(database) { ... } block at a well-defined boundary (typically a use case or service method). No implicit “request transaction”.
• Bitemporal columns (valid_from, valid_to, tx_from, tx_to) are part of every business-state table. See Bitemporal Persistence.
• Schema migrations are owned by Flyway, not Exposed. Exposed describes the current schema; Flyway migrations under db/migration/ evolve it.
• Error handling: SQL errors are caught at the boundary and mapped to the AppError sealed hierarchy. See Exception Handling.

Authoritative references

• Exposed documentation — official.
• Exposed wiki on GitHub — deeper reference for the DSL and Table API.

See also

• The kotlin-coding skill — Result handling and AppError patterns applied at every Exposed boundary.
• The unit-tests-infra skill — ContainerizedPostgres and the Harness pattern for database-backed tests.
• Data Authority Pattern — module boundary rules around shared tables.