光滑和按选项列过滤 [英] Slick and filtering by Option columns

问题描述

我正在尝试使用 Scala Slick 1.0.1 过滤可选日期列.

I'm trying to filter against an optional date column with Scala Slick 1.0.1.

可能我只是没看到，但我有一张看起来像这样的桌子:

It may be I just don't see it, but I've got a table that looks something like this:

case class UserRole(id:UUID, userID:UUID, role:String)
object UserRole extends Table[UserRole]("User_Role")  {

  //(id: Long = 0l, name: String, active: Boolean) extends KeyedEntity[Long] {
  def id = column[UUID]("ID", O.PrimaryKey)
  def userID = column[UUID]("user_id")
  def vendorID = column[UUID]("vendor_id")
  def role = column[String]("role")
  def user = foreignKey("user_FK", userID, User)(_.id)

  def start = column[java.sql.Date]("startDate")
  def endDate = column[Option[java.sql.Date]]("endDate")

  def * = id ~ userID ~ role  <> (UserRole.apply _, UserRole.unapply _)
}

您会在那里看到 endDate 是可选的.

You'll see there that the endDate is optional.

如何构造一个查询，在其中进行过滤，以便 endDate 可以为 NULL/None 或大于当前 (db) 日期?仅供参考，我通常使用嵌入式 api

How do I construct a query where I filter so endDate can be NULL/None or greater than the current (db) date? FYI, I'm generally using the embedded api

谢谢

推荐答案

这不是很好(关于 null.asInstanceOf 的部分)，但我认为它会起作用.我从一个旧的 Scala 查询帖子中得到了这个想法，所以我不知道 slick 是否为此提供了更好的东西，但是当我查看查询的结果 selectStatement 时，它看起来是正确的:

This is not pretty (the part about null.asInstanceOf), but I think it will work. I got that idea from an old Scala Query post, so I don't know if slick ever put something better in for that, but when I looked at the resulting selectStatement from the query, it looked correct:

val now = new java.sql.Date(System.currentTimeMillis())
val query = for {
  role <- UserRole
  if (role.endDate === null.asInstanceOf[Option[java.sql.Date]] || role.endDate > now)
} yield role

编辑

感谢@MartinKolinek 的评论，这段代码也可以工作，而且更简洁，可能是更好的做事方式:

Thanks to the comment by @MartinKolinek, this code will also work and is much cleaner and probably the better way to do things:

val now = new java.sql.Date(System.currentTimeMillis())
val query = for {
  role <- UserRole
  if (role.endDate.isNull || role.endDate > now)
} yield role

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