У меня есть запрос в slick с подзапросом, который выглядит так:
(User join Address on (_.id === _.userId))
.map { case (user, address) =>
(
user.id,
address.id,
address.street,
Detail.filter(_.userId === user.id).map(_.value).first
)
}.list
что вызывает исключение:
[SlickException: No type for symbol s2 found for Ref s2]
В чем проблема? Чтобы было ясно, это упрощенная версия моего производственного кода для удобства, однако ошибка точно такая же.
Стек: Slick 2.1 / Scala 2.11.4 / Play Framework 2.3.6 / Java 8
Классы таблиц генерируются гладким генератором кода (я бы хотел, чтобы так и было):
package db
// AUTO-GENERATED Slick data model
/** Stand-alone Slick data model for immediate use */
object Tables extends {
val profile = scala.slick.driver.PostgresDriver
} with Tables
/** Slick data model trait for extension, choice of backend or usage in the cake pattern. (Make sure to initialize this late.) */
trait Tables {
val profile: scala.slick.driver.JdbcProfile
import profile.simple._
import scala.slick.model.ForeignKeyAction
// NOTE: GetResult mappers for plain SQL are only generated for tables where Slick knows how to map the types of all columns.
import scala.slick.jdbc.{GetResult => GR}
/** DDL for all tables. Call .create to execute. */
lazy val ddl = Address.ddl ++ Detail.ddl ++ User.ddl
/** Entity class storing rows of table Address
* @param id Database column id DBType(serial), AutoInc, PrimaryKey
* @param userId Database column user_id DBType(int4)
* @param street Database column street DBType(varchar), Length(2147483647,true) */
case class AddressRow(id: Int, userId: Int, street: String)
/** GetResult implicit for fetching AddressRow objects using plain SQL queries */
implicit def GetResultAddressRow(implicit e0: GR[Int], e1: GR[String]): GR[AddressRow] = GR{
prs => import prs._
AddressRow.tupled((<<[Int], <<[Int], <<[String]))
}
/** Table description of table address. Objects of this class serve as prototypes for rows in queries. */
class Address(_tableTag: Tag) extends Table[AddressRow](_tableTag, "address") {
def * = (id, userId, street) <> (AddressRow.tupled, AddressRow.unapply)
/** Maps whole row to an option. Useful for outer joins. */
def ? = (id.?, userId.?, street.?).shaped.<>({r=>import r._; _1.map(_=> AddressRow.tupled((_1.get, _2.get, _3.get)))}, (_:Any) => throw new Exception("Inserting into ? projection not supported."))
/** Database column id DBType(serial), AutoInc, PrimaryKey */
val id: Column[Int] = column[Int]("id", O.AutoInc, O.PrimaryKey)
/** Database column user_id DBType(int4) */
val userId: Column[Int] = column[Int]("user_id")
/** Database column street DBType(varchar), Length(2147483647,true) */
val street: Column[String] = column[String]("street", O.Length(2147483647,varying=true))
}
/** Collection-like TableQuery object for table Address */
lazy val Address = new TableQuery(tag => new Address(tag))
/** Entity class storing rows of table Detail
* @param id Database column id DBType(serial), AutoInc, PrimaryKey
* @param userId Database column user_id DBType(int4)
* @param value Database column value DBType(varchar), Length(2147483647,true) */
case class DetailRow(id: Int, userId: Int, value: String)
/** GetResult implicit for fetching DetailRow objects using plain SQL queries */
implicit def GetResultDetailRow(implicit e0: GR[Int], e1: GR[String]): GR[DetailRow] = GR{
prs => import prs._
DetailRow.tupled((<<[Int], <<[Int], <<[String]))
}
/** Table description of table detail. Objects of this class serve as prototypes for rows in queries. */
class Detail(_tableTag: Tag) extends Table[DetailRow](_tableTag, "detail") {
def * = (id, userId, value) <> (DetailRow.tupled, DetailRow.unapply)
/** Maps whole row to an option. Useful for outer joins. */
def ? = (id.?, userId.?, value.?).shaped.<>({r=>import r._; _1.map(_=> DetailRow.tupled((_1.get, _2.get, _3.get)))}, (_:Any) => throw new Exception("Inserting into ? projection not supported."))
/** Database column id DBType(serial), AutoInc, PrimaryKey */
val id: Column[Int] = column[Int]("id", O.AutoInc, O.PrimaryKey)
/** Database column user_id DBType(int4) */
val userId: Column[Int] = column[Int]("user_id")
/** Database column value DBType(varchar), Length(2147483647,true) */
val value: Column[String] = column[String]("value", O.Length(2147483647,varying=true))
}
/** Collection-like TableQuery object for table Detail */
lazy val Detail = new TableQuery(tag => new Detail(tag))
/** Entity class storing rows of table User
* @param id Database column id DBType(serial), AutoInc, PrimaryKey
* @param name Database column name DBType(varchar), Length(2147483647,true) */
case class UserRow(id: Int, name: String)
/** GetResult implicit for fetching UserRow objects using plain SQL queries */
implicit def GetResultUserRow(implicit e0: GR[Int], e1: GR[String]): GR[UserRow] = GR{
prs => import prs._
UserRow.tupled((<<[Int], <<[String]))
}
/** Table description of table user. Objects of this class serve as prototypes for rows in queries. */
class User(_tableTag: Tag) extends Table[UserRow](_tableTag, "user") {
def * = (id, name) <> (UserRow.tupled, UserRow.unapply)
/** Maps whole row to an option. Useful for outer joins. */
def ? = (id.?, name.?).shaped.<>({r=>import r._; _1.map(_=> UserRow.tupled((_1.get, _2.get)))}, (_:Any) => throw new Exception("Inserting into ? projection not supported."))
/** Database column id DBType(serial), AutoInc, PrimaryKey */
val id: Column[Int] = column[Int]("id", O.AutoInc, O.PrimaryKey)
/** Database column name DBType(varchar), Length(2147483647,true) */
val name: Column[String] = column[String]("name", O.Length(2147483647,varying=true))
}
/** Collection-like TableQuery object for table User */
lazy val User = new TableQuery(tag => new User(tag))
}
ОБНОВЛЕНИЕ: теперь я понимаю, что .first в подзапросе выдает String там, где мне действительно нужно, чтобы это было Column[String] Что-то вроде
Detail.filter(_.userId === user.id).map(_.value).max
работает, но тогда подзапрос выглядит так:
SELECT MAX(value) FROM Detail WHERE userId = user.id
когда мне нужно, чтобы это выглядело примерно так:
SELECT value FROM Detail WHERE userId = user.id LIMIT 1
