scala - 在 PostgreSQL 和 Slick 中使用自动递增字段

Question

如何使用带有 Slick 映射表的 AutoInc 键将记录插入到 PostgreSQL 中？如果我在案例类中使用 和 Option 作为 id 并将其设置为 None，那么 PostgreSQL 将在插入时提示该字段不能为空。这适用于 H2，但不适用于 PostgreSQL:

//import scala.slick.driver.H2Driver.simple._
//import scala.slick.driver.BasicProfile.SimpleQL.Table
import scala.slick.driver.PostgresDriver.simple._
import Database.threadLocalSession

object TestMappedTable extends App{

    case class User(id: Option[Int], first: String, last: String)

    object Users extends Table[User]("users") {
        def id = column[Int]("id", O.PrimaryKey, O.AutoInc)
        def first = column[String]("first")
        def last = column[String]("last")
        def * = id.? ~ first ~ last <> (User, User.unapply _)
        def ins1 = first ~ last returning id
        val findByID = createFinderBy(_.id)
        def autoInc = id.? ~ first ~ last <> (User, User.unapply _) returning id
    }

 // implicit val session = Database.forURL("jdbc:h2:mem:test1", driver = "org.h2.Driver").createSession()
    implicit val session = Database.forURL("jdbc:postgresql:test:slicktest",
                           driver="org.postgresql.Driver",
                           user="postgres",
                           password="xxx")

  session.withTransaction{
    Users.ddl.create

    // insert data
    print(Users.insert(User(None, "Jack", "Green" )))
    print(Users.insert(User(None, "Joe", "Blue" )))
    print(Users.insert(User(None, "John", "Purple" )))
    val u = Users.insert(User(None, "Jim", "Yellow" ))
  //  println(u.id.get)
    print(Users.autoInc.insert(User(None, "Johnathan", "Seagul" )))
  }
  session.withTransaction{
    val queryUsers = for {
    user <- Users
  } yield (user.id, user.first)
  println(queryUsers.list)

  Users.where(_.id between(1, 2)).foreach(println)
  println("ID 3 -> " + Users.findByID.first(3))
  }
}

将上述内容与 H2 一起使用会成功，但如果我将其注释掉并更改为 PostgreSQL，则会得到:

[error] (run-main) org.postgresql.util.PSQLException: ERROR: null value in column "id" violates not-null constraint
org.postgresql.util.PSQLException: ERROR: null value in column "id" violates not-null constraint

Answer 1

这在这里工作:

object Application extends Table[(Long, String)]("application") {   
    def idlApplication = column[Long]("idlapplication", O.PrimaryKey, O.AutoInc)
    def appName = column[String]("appname")
    def * = idlApplication ~ appName
    def autoInc = appName returning idlApplication
}

var id = Application.autoInc.insert("App1")

这就是我的 SQL 的样子:

CREATE TABLE application
(idlapplication BIGSERIAL PRIMARY KEY,
appName VARCHAR(500));

更新:

与 User 映射表有关的具体问题(如问题中所示)可以按如下方式解决:

  def forInsert = first ~ last <>
    ({ (f, l) => User(None, f, l) }, { u:User => Some((u.first, u.last)) })

这来自test cases in the Slick git repository .