Table types

In Exposed, the Table class is the core abstraction for defining database tables. This class provides methods to define various column types, constraints, and other table-specific properties.

Table is located in the org.jetbrains.exposed.sql package of the exposed-core module.

The following example defines a table with an auto-incrementing integer id column and a string name column:

        import org.jetbrains.exposed.sql.Table

        object Cities : Table("cities") {
            val id = integer("id").autoIncrement()
            val name = varchar("name", 50)
        }
    

        CREATE TABLE IF NOT EXISTS CITIES (ID INT AUTO_INCREMENT NOT NULL, "name" VARCHAR(50) NOT NULL)
    

For more information on defining and configuring tables in Exposed, see Working with tables.

While Table is the foundational class for defining tables in DSL, you can also use the IdTable subclasses from the DAO API for convenience. For example, to provide an auto-incrementing id column of type Int, you can use the IntIdTable subtype:

        object StarWarsFilms : IntIdTable() {
            val sequelId = integer("sequel_id").uniqueIndex()
            val name = varchar("name", 50)
            val director = varchar("director", 50)
        }
    

It is important to note that the id column in this case is of type Column<EntityID<Int>>. The EntityID wrapper ensures that the id values are handled consistently across the DSL and DAO APIs.

To access the id column value, you need to use the .value property:

val idValue = StarWarsFilms.id.value

For more information on IdTable, see the DAO documentation.

Last modified: 30 October 2024