在 Anorm 中保存新对象时如何检索主键 [英] How to Retrieve the Primary Key When Saving a New Object in Anorm

问题描述

我正在使用 Scala Play！使用 Anorm 将数据模型持久化到数据库的框架.我按照示例代码 这里 :

I'm using Scala Play! framework with Anorm to persist the data model to the database. I followed the example code here :

case class Bar(id: Pk[Long], name: String)

object Bar {

  val simple = {
    get[Pk[Long]]("id") ~
    get[String]("name") map {
      case id~name => Bar(id, name)
    }
  }

  def findAll(): Seq[Bar] = {
    DB.withConnection { implicit connection =>
      SQL("select * from bar").as(Bar.simple *)
    }
  }

  def create(bar: Bar): Unit = {
    DB.withConnection { implicit connection =>
      SQL("insert into bar(name) values ({name})").on(
        'name -> bar.name
      ).executeUpdate()
    }
  }

}

尝试对其进行扩展，我想检索刚刚创建的主键并将其存储在案例类中.

Trying to expand on it, I want to retrieve the primary key just created and store it in the case class.

如何检索主键?

推荐答案

使用 executeInsert 方法代替 executeUpdate.注意到这里，前一个方法返回Option[T] 其中 T 是主键的类型.

Use the executeInsert method instead of executeUpdate. Noted here, the foremer method returns Option[T] where T is the type of the primary key.

您可以使用 match 语句提取值:

You can extract the value with a match statement:

    DB.withConnection { implicit connection =>
        SQL(...).executeInsert()
    } match {
        case Some(long) => long // The Primary Key
        case None       => ...
    }

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