更新和删除在 play-slick 中不起作用的查询

Question

我正在尝试为 play-slick 编写一个简单的 CRUD 应用程序。我可以插入数据库并显示所有用户，但我不能更新或删除用户。我的全部代码在下面

package models

import javax.inject.{ Inject, Singleton }
import play.api.db.slick.DatabaseConfigProvider
import slick.jdbc.JdbcProfile

import scala.concurrent.{ Future, ExecutionContext }

/**
 * A repository for people.
 *
 * @param dbConfigProvider The Play db config provider. Play will inject this for you.
 */
@Singleton
class PersonRepository @Inject() (dbConfigProvider: DatabaseConfigProvider)(implicit ec: ExecutionContext) {
  // We want the JdbcProfile for this provider
  private val dbConfig = dbConfigProvider.get[JdbcProfile]

  // These imports are important, the first one brings db into scope, which will let you do the actual db operations.
  // The second one brings the Slick DSL into scope, which lets you define the table and other queries.
  import dbConfig._
  import profile.api._

  /**
   * Here we define the table. It will have a name of people
   */
  private class PeopleTable(tag: Tag) extends Table[Person](tag, "people") {

    /** The ID column, which is the primary key, and auto incremented */
    def id = column[Long]("id", O.PrimaryKey, O.AutoInc)

    /** The name column */
    def name = column[String]("name")

    /** The age column */
    def age = column[Int]("age")

    /**
     * This is the tables default "projection".
     *
     * It defines how the columns are converted to and from the Person object.
     *
     * In this case, we are simply passing the id, name and page parameters to the Person case classes
     * apply and unapply methods.
     */
    def * = (id, name, age) <> ((Person.apply _).tupled, Person.unapply)
  }

  /**
   * The starting point for all queries on the people table.
   */
  private val people = TableQuery[PeopleTable]

  /**
   * Create a person with the given name and age.
   *
   * This is an asynchronous operation, it will return a future of the created person, which can be used to obtain the
   * id for that person.
   */
  def create(name: String, age: Int): Future[Person] = db.run {
    // We create a projection of just the name and age columns, since we're not inserting a value for the id column
    (people.map(p => (p.name, p.age))
      // Now define it to return the id, because we want to know what id was generated for the person
      returning people.map(_.id)
      // And we define a transformation for the returned value, which combines our original parameters with the
      // returned id
      into ((nameAge, id) => Person(id, nameAge._1, nameAge._2))
    // And finally, insert the person into the database
    ) += (name, age)
  }

  /**
   * List all the people in the database.
   */
  def list(): Future[Seq[Person]] = db.run {
    people.result
  }

  def del(id: Int) : Future[Seq[Person]] = db.run {
   people.filter(_.id === id).delete

  }

  def update (id: Int, name: String) : Future[Seq[Person]] = {
    db.run(people.filter(_.id === id).update("john"))

  }
}

也有可能我排除了一些导入，所以请检查我是否需要导入任何东西。

我也遇到这个错误，但我不知道它是什么意思：

type mismatch; found : UserData.this.dbConfig.profile.ProfileAction[Int,slick.dbio.NoStream,slick.dbio.Effect.Write] (which expands to) slick.sql.FixedSqlAction[Int,slick.dbio.NoStream,slick.dbio.Effect.Write] required: slick.dbio.DBIOAction[Seq[models.User],slick.dbio.NoStream,Nothing]

Answer 1

我认为您在删除或更新时遇到了 return 类型的问题。据我所知，他们 return 已修改的行数。

试试这个：

def del(id: Int) : Future[Int] = db.run {
  people.filter(_.id === id).delete
}

def update (id: Int, name: String) : Future[Int] = {
  db.run(people.filter(_.id === id).update("john"))
}

更新和删除在 play-slick 中不起作用的查询

Update and delete queries not working in play-slick

scala

crud

playframework

slick