我正在編寫一個使用MongoDB作爲數據庫和ReactiveMongo作爲驅動程序的Scala Web應用程序。MongoDB在已經存在的情況下更新文檔ReactiveMongo
我有一個名爲recommendation.correlation
的集合,其中我保存了產品和類別之間的關聯。
文檔具有以下形式:
{ "_id" : ObjectId("544f76ea4b7f7e3f6e2db224"), "category" : "c1", "attribute" : "c3:p1", "value" : { "average" : 0, "weight" : 3 } }
現在我正在寫一個方法如下:
def calculateCorrelation: Future[Boolean] = {
def calculate(category: String, tag: String, similarity: List[Similarity]): Future[(Double, Int)] = {
println("Calculate correlation of " + category + " " + tag)
val value = similarity.foldLeft(0.0, 0)((r, c) => if(c.tag1Name.split(":")(0) == category && c.tag2Name == tag) (r._1 + c.eq, r._2 + 1) else r
) //fold the tags
val sum = value._1
val count = value._2
val result = if(count > 0) (sum/count, count) else (0.0, 0)
Future{result}
}
play.Logger.debug("Start Correlation")
Similarity.all.toList flatMap { tagsMatch =>
val tuples =
for {
i<- tagsMatch
} yield (i.tag1Name.split(":")(0), i.tag2Name) // create e List[(String, String)] containing the category and productName
val res = tuples map { el =>
calculate(el._1, el._2, tagsMatch) flatMap { value =>
val correlation = Correlation(el._1, el._2, value._1, value._2) // create the correlation
val query = Json.obj("category" -> value._1, "attribute" -> value._2)
Correlations.find(query).one flatMap(element => element match {
case Some(x) => Correlations.update(query, correlation) flatMap {status => status match {
case LastError(ok, _, _, _, _, _, _) => Future{true}
case _ => Future{false}
}
}
case None => Correlations.save(correlation) flatMap {status => status match {
case LastError(ok, _, _, _, _, _, _) => Future{true}
case _ => Future{false}
}
}
}
)
}
}
val result = if(res.exists(_ equals false)) false else true
Future{result}
}
的問題是,該方法插入複製文件。 爲什麼會發生這種情況?
我已經解決了使用db.recommendation.correlation.ensureIndex({"category": 1, "attribute": 1}, {"unique": true, "dropDups":true })
,但我怎樣才能解決這個問題,而不使用索引?
怎麼回事?