kotlin - 使用Jetbrains的Exposed库的字符串主键-Kotlin

Question

我在弄清楚如何使用字符串主键编写表以及表的实体时遇到问题。无论我将IdTable<String>设置为Table类型还是尝试将其与纯Table一起使用均无济于事。

Answer 1

如果您确实需要将String作为主键，请执行以下操作:

/*
 * Base class for entities with string id
 */
abstract class StringEntityClass<out E: Entity<String>>(table: IdTable<String>, entityType: Class<E>? = null) : EntityClass<String, E>(table, entityType)

/*
 * Base class for table objects with string id
 */
open class StringIdTable(name: String = "", columnName: String = "id", columnLength: Int = 10) : IdTable<String>(name) {
    override val id: Column<EntityID<String>> = varchar(columnName, columnLength).entityId()
    override val primaryKey by lazy { super.primaryKey ?: PrimaryKey(id) }
}

// Sample usage    

object MyTableWithStringId : StringIdTable() {
    // ...
}

class MyEntityWithStringId(id: EntityID<String>) : Entity<String>(id) {
    // ...
}