Type Conversions

Type conversions

Custom type conversions

Sometimes you need to convert database values to your own custom types and vice versa. To do that, register conversions when configuring your DbConnectionProvider:

val db = JdbcConnectionProvider(dataSource) {
    conversions {
        // register conversions from database and to database types separately
        registerConversionFromDatabase(EmailAddress::parse)
        registerConversionToDatabase(EmailAddress::toString)

        // or register both directions with one call
        registerConversions<String, EmailAddress>(
            fromDatabase = EmailAddress::parse,
            toDatabase = EmailAddress::toString,
        )
    }
}

Enums

By default, enums are persisted using a value you choose — for example their name or ordinal:

val db = JdbcConnectionProvider(dataSource) {
    conversions {
        registerEnum(MyEnum::name)
    }
}

The value doesn’t need to be the name or ordinal — any property works, so you can persist a stable code that’s independent of how the enum constants happen to be named or ordered in your Kotlin code:

enum class Status(val code: String) {
    ACTIVE("A"),
    INACTIVE("I"),
    PENDING("P"),
}

val db = JdbcConnectionProvider(dataSource) {
    conversions {
        registerEnum(Status::code)
    }
}