使用Slick

Question

我在使用光滑构成链式插入查询时遇到问题。我想插入一行，返回主键，然后将一个带有外键的新行插入我刚刚插入的行。

我尝试使用flatmap将第一个插入的结果链接到第二个插入中，但是下面的代码似乎只执行第一个插入到＆＃34;用户＆＃34;表，而不是第二次插入＆＃34;列表＆＃34;

示例代码如下，请提前感谢您的帮助！

package com.example.jdbc

import slick.driver.PostgresDriver.api._

import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{Failure, Success}

object DatabaseControllerMin {

  lazy val db = Database.forConfig("postgres")

  lazy val recreateTables = DBIO.seq(
    // drop the old tables
    (users.schema ++ lists.schema).drop,
    // Create the tables, including primary and foreign keys
    (users.schema ++ lists.schema).create
  )

  class Users(tag: Tag) extends Table[(Int, String)](tag, "users") {

    def id = column[Int]("user_id", O.PrimaryKey, O.AutoInc)

    def name = column[String]("name")

    def * = (id, name)
  }

  lazy val users = TableQuery[Users]

  class Lists(tag: Tag) extends Table[(Int, String, Int)](tag, "lists") {

    def id = column[Int]("list_id", O.PrimaryKey, O.AutoInc)

    def name = column[String]("name")

    def userId = column[Int]("user_id")

    def * = (id, name, userId)

    def user = foreignKey("users", userId, users)(_.id)
  }

  lazy val lists = TableQuery[Lists]

  def recreateDatabase = {
    try {
      val q = recreateTables andThen {
        users returning users.map(_.id) into ((user, id) => user.copy(_1 = id)) +=(0, "Tyler")
      }  flatMap {
        user => {
          lists +=(0, s"${user._2}'s List", user._1)
        }
      }
      db.run(q)
    } finally db.close
  }

  def main(args: Array[String]) {
    recreateDatabase onComplete {
      case Success(x) => {
        println("Success!!!")
      }
      case Failure(t) => {
        println("Failure")
        t.printStackTrace
      }
    }
  }
}