如何在 Scala Slick 中使用枚举?

How to use Enums in Scala Slick?(如何在 Scala Slick 中使用枚举?)

问题描述

想要将 MySQL INT 位掩码映射到 Slick.

Want to map MySQL INT bitmask to Slick.

我找到了这个，但是如何使用它没有什么问题

I've found this but have little problem how to use it

https://github.com/nafg/slick-additions/blob/master/src/main/scala/scala/slick/additions/Enum.scala

任何帮助我应该如何定义对象，即

Any help how should I define object for i.e.

mysql 列 INT(3) 带有包含 3 个值的 Enum:让我们在此处将它们命名为 a、b、c.

mysql column INT(3) with Enum containing 3 values: lets name them a,b,c here.

推荐答案

我通过以下方式解决了 Enums 的问题(以您的值为例):

I solved the problem with Enums in the following way (taking your values for an example):

import play.api.db.slick.DB
import play.api.db.slick.Config.driver.simple._


sealed trait MyEnum
case object MyEnumA extends MyEnum
case object MyEnumB extends MyEnum
case object MyEnumC extends MyEnum

object MyEnumMapper {
  val string_enum_mapping:Map[String,MyEnum] = Map(
     "a" -> MyEnumA,
     "b" -> MyEnumB,
     "c" -> MyEnumC
  )
  val enum_string_mapping:Map[MyEnum,String] = string_enum_mapping.map(_.swap)
  implicit val myEnumStringMapper = MappedTypeMapper.base[MyEnum,String](
    e => enum_string_mapping(e),
    s => string_enum_mapping(s)
  )
}

import MyEnumMapper._

case class MyData(
 ......
 enumValue: MyEnum,
 .....
)

................

object MyDataTable extends Table[MyData]("<table_name>") {
......
def enumValue = column[MyEnum]("<field_name>")
.....

.... /* whatever lifted or direct slick calls you want */ 

}

如果在 Play 2.1 和 Play 2.2、Slick 1.0.0 和 MariaDB 5.5(与 MySQL 相同)中都对我有用

If works for me in both Play 2.1 and Play 2.2, Slick 1.0.0 and MariaDB 5.5 (same as MySQL)

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