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我正在为我在 Scala 中使用 Play 2.1.1 和 PlaySlick 作为数据库映射器编写的程序编写案例类。该申请涉及引文。我们有一个超过 22 个字段的引文表，因此我们将这些字段缩小到 22 个，这是我们真正需要做的大多数事情。代码如下：

package models
import play.api.db.slick.Config.driver._

case class Citation(citation_id: Int, pubtype: String, abs: String, keywords: String,      
                    doi: String, url: String, booktitle: String, chapter: String, edition: String, editor:       
                    String, translator: String, journal: String, month: String, number: String, pages: 
                    String, publisher: String, location: String, title: String, volume: String, year: 
                    String, raw: String, owner: String)

object Citations extends Table[Citation]("citations") {
  def citation_id = column[Int]("citation_id", O.PrimaryKey, O.AutoInc)
  def pubtype = column[String]("pubtype")
  def abs = column[String]("abstract")
  def keywords = column[String]("keywords")
  def doi = column[String]("doi")
  def url = column[String]("url")
  def booktitle = column[String]("booktitle")
  def chapter = column[Int]("chapter")
  def edition = column[String]("edition")
  def editor = column[String]("editor")
  def translator = column[String]("translator")
  def journal = column[String]("journal")
  def month = column[Int]("month")
  def number = column[Int]("number")
  def pages = column[String]("pages")
  def publisher = column[String]("publisher")
  def location = column[String]("location")
  def title = column[String]("title")
  def volume = column[String]("volume")
  def year = column[String]("year")
  def raw = column[String]("raw")
  def owner = column[String]("owner") 

  def * = (citation_id ~ pubtype ~ abs ~ keywords ~ doi ~ url ~ booktitle ~ chapter ~   edition ~ editor ~ translator ~ journal ~ month ~ number ~ pages ~ publisher ~ location ~ title ~ volume ~ year ~ raw ~ owner).<>[Citation](Citation,Citation unapply _)
}

然而，我们在上面的代码中得到了这个令人讨厌的错误：

Description Resource    Path    Location    Type
overloaded method value <> with alternatives:   (f: (Int, String, String, String,     String, String, String, Int, String, String, String, String, Int, Int, String, String,    String, String, String, String, String, String) => models.Citation,g: models.Citation =>  Option[(Int, String, String, String, String, String, String, Int, String, String, String,  String, Int, Int, String, String, String, String, String, String, String,  String)])scala.slick.lifted.MappedProjection[models.Citation,(Int, String, String, String,  String, String, String, Int, String, String, String, String, Int, Int, String, String,  String, String, String, String, String, String)] <and>   (f: ((Int, String, String, String,  String, String, String, Int, String, String, String, String, Int, Int, String, String,  String, String, String, String, String, String)) => models.Citation,g: models.Citation => Option[(Int, String, String, String, String, String, String, Int, String, String, String, String, Int, Int, String, String, String, String, String, String, String, String)])scala.slick.lifted.MappedProjection[models.Citation,(Int, String, String, String, String, String, String, Int, String, String, String, String, Int, Int, String, String, String, String, String, String, String, String)]  cannot be applied to   (models.Citation.type, models.Citation => Option[(Int, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String, String)])  Citations.scala /myapp/app/models   line 39 Scala Problem`

默认投影有问题，但我不确定它是什么。我们正处于 22 arg 限制，但如果我们将其缩小到 21 或 20，我们仍然会得到相同的错误。

任何帮助将不胜感激。谢谢！

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1 回答 1

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问题是chapter、month和number字段的类型。这些在您的案例类中定义为String ，但在表定义中定义为Int 。

于 2013-09-30T21:01:56.377 回答