JetBrains Exposed ORM patterns including DSL queries, DAO pattern, transactions, HikariCP connection pooling, Flyway migrations, and repository pattern. Use when working with the Exposed ORM — DSL or DAO queries, transactions, pooling, or migrations.

Kotlin Exposed Patterns Comprehensive patterns for database access with JetBrains Exposed ORM, including DSL queries, DAO, transactions, and production ready configuration. When to Use Setting up database access with Exposed Writing SQL queries using Exposed DSL or DAO Configuring connection pooling with HikariCP Creating database migrations with Flyway Implementing the repository pattern with Exposed Handling JSON columns and complex queries How It Works Exposed provides two query styles: DSL for direct SQL like expressions and DAO for entity lifecycle management. HikariCP manages a pool of reusable database connections configured via HikariConfig . Flyway runs versioned SQL migration scripts at startup to keep the schema in sync. All database operations run inside newSuspendedTransaction blocks for coroutine safety and atomicity. The repository pattern wraps Exposed queries behind an interface so business logic stays decoupled from the data layer and tests can use an in memory H2 database. Examples DSL Query DAO Entity Usage HikariCP Configuration Database Setup HikariCP Connection Pooling Flyway Migrations Migration Files Table Definitions DSL Style Tables Composite Tables DSL Queries Basic CRUD Advanced Queries Pagination Batch Operations DAO Pattern Entity Definitions DAO Operations Transactions Suspend Transaction Support Transaction Isolation Repository Pattern Interface Definition Exposed Implementation JSON Columns JSONB with kotlinx.serialization Testing with Exposed In Memory Database for Tests Gradle Dependencies Quick Reference: Exposed Patterns Pattern Description object Table : UUIDTable("name") Define table with UUID primary key newSuspendedTransaction { } Coroutine safe transaction block Table.selectAll().where { } Query with conditions Table.insertAndGetId { } Insert and return generated ID Table.update({ condition }) { } Update matching rows Table.deleteWhere { } Delete matching rows Table.batchInsert(items) { } Efficient bulk insert innerJoin / leftJoin Join tables orderBy / limit / offset Sort and paginate count() / sum() / avg() Aggregation functions Remember : Use the DSL style for simple queries and the DAO style when you need entity lifecycle management. Always use newSuspendedTransaction for coroutine support, and wrap database operations behind a repository interface for testability.

kotlin-exposed-patterns