我希望能够使用Slick
创建一个查询,让我以动态的方式过滤左连接
case class Player(
id: Long,
createdAt: DateTime,
lastModificationDate: DateTime,
name: String
)
class PlayerTable(tag: Tag) extends Table[Player](tag, "players") {
def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
def createdAt = column[DateTime]("createdAt")
def lastModificationDate = column[DateTime]("lastModificationDate")
def name = column[String]("name")
override def * : ProvenShape[Player] = (
id,
createdAt,
lastModificationDate,
updatedAt,
name
) <> (Player.tupled, Player.unapply)
}
case class PlayerGame(
id: Long,
createdAt: DateTime,
lastModificationDate: DateTime,
playerId: Long,
level: Int,
status: String
)
class PlayerGameTable(tag: Tag) extends Table[PlayerGame](tag, "player_games") {
def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
def createdAt = column[DateTime]("createdAt")
def lastModificationDate = column[DateTime]("lastModificationDate")
def playerId = column[Long]("playerId")
def level = column[Int]("level")
def status = column[String]("status")
override def * : ProvenShape[PlayerGame] = (
id,
createdAt,
lastModificationDate,
playerId,
level,
status
) <> (PlayerGame.tupled, PlayerGame.unapply)
}
我想用Slick编写这样的查询,其中WHERE CLAUSE
是动态的。我写了两个例子
SELECT *
FROM players
LEFT JOIN player_games AS playerGamesOne ON players.id = playerGamesOne.playerId AND playerGamesOne.level = 1
LEFT JOIN player_games AS playerGamesTwo ON players.id = playerGamesTwo.playerId AND playerGamesTwo.level = 2
WHERE playerGamesOne.status LIKE 'gameOver'
OR playerGamesTWO.status LIKE 'gameOver'
SELECT *
FROM players
LEFT JOIN player_games AS playerGamesOne ON players.id = playerGamesOne.playerId AND playerGamesOne.level = 1
LEFT JOIN player_games AS playerGamesTwo ON players.id = playerGamesTwo.playerId AND playerGamesTwo.level = 2
WHERE playerGamesOne.status LIKE 'playing'
OR playerGamesTwo.status NOT LIKE 'gameOver'
我正在尝试这样的东西,但我得到Rep[Option[PlayerGameTable]]
作为参数。也许有不同的方式来做这样的事情
val baseQuery = for {
((p, g1), g2) <- PlayerTable.playerQuery joinLeft
PlayerGameTable.playerGameQuery ON ((x, y) => x.id === y.playerId && y.level === 1) joinLeft
PlayerGameTable.playerGameQuery ON ((x, y) => x._1.id === y.playerId && y.level === 2)
} yield (p, g1, g2)
private def filterPlayerGames(gameStatus: String, playerGamesOneOpt: Option[PlayerGameTable], playerGamesTwoOpt: Option[PlayerGameTable]) = {
(gameStatus, playerGamesOneOpt, playerGamesOneOpt) match {
case (gameStatus: String, Some(playerGamesOne: PlayerGameTable), Some(playerGamesOne: PlayerGameTable)) if gameStatus == "gameOver" => playerGamesOne.status === "gameOver" || playerGamesTwo.status === "gameOver"
}
}
这是一个复杂的问题,如果问题不明确请告诉我,我会尽力澄清
有几个问题:
underscore
子句中使用的ON
占位符不会按照预期的方式工作_.level = something
是一项任务,而非条件假设PlayerTable.playerQuery
是TableQuery[PlayerTable]
而PlayerGameTable.playerGameQuery
是TableQuery[PlayerGameTable]
,你的baseQuery
应该是这样的:
val baseQuery = for {
((p, g1), g2) <- PlayerTable.playerQuery joinLeft
PlayerGameTable.playerGameQuery on ((x, y) => x.id === y.playerId && y.level === 1) joinLeft
PlayerGameTable.playerGameQuery on ((x, y) => x._1.id === y.playerId && y.level === 2)
} yield (p, g1, g2)
我并不完全清楚你的filterPlayerGames
方法将如何处理动态条件。我也不认为任何过滤包装方法都足够灵活,可以用任意and/or/negation
算子覆盖多个条件。我建议您使用baseQuery
作为必要的join
s并在其上构建过滤查询,类似于下面的内容:
val query1 = baseQuery.filter{ case (_, g1, g2) =>
g1.filter(_.status === "gameOver").isDefined || g2.filter(_.status === "gameOver").isDefined
}
val query2 = baseQuery.filter{ case (_, g1, g2) =>
g1.filter(_.status === "playing").isDefined || g2.filter(_.status =!= "gameOver").isDefined
}
请注意,使用left join
s,g1
和g2
属于Option类型,因此isDefined
适用于or
操作。
另外注意,鉴于您的过滤条件仅在PlayerGameTable
上,在filtering
s之前执行join
可能更有效。