1
的docs注:
要在$匹配階段使用$文本中,$匹配階段必須是第一階段管道。
一些示例JSON:
{"pid":"b00l16vp", "title": "in our time","categories":{"category1":["factual", "arts culture and the media", "history"]}}
{"pid":"b0079mpp", "title": "doctor who", "categories":{"category2":["childrens", "entertainment and comedy", "animation"],"category1":["signed"]}}
{「pid":"b00htbn3"}
{「pid":"b00gdhqw","categories":{"category2":["factual"],"category3":["scotland"],"category4":["lifestyle and leisure", "food and drink"],"category1":["entertainment", "games and quizzes"]}}
我有以下查詢:
List<BasicDBObject> pipeline = new ArrayList<>()
BasicDBObject criteria = new BasicDBObject()
BasicDBObject theProjections = new BasicDBObject()
AggregateIterable iterable
//value is coming from a parameter
if (value != null) {
//a text index has been created on the title field
criteria.put('$text', new BasicDBObject('$search', value))
}
//cats is coming from a parameter but it will be an array of Strings
if (cats.length != 0) {
ArrayList<BasicDBObject> orList = new ArrayList<>()
ArrayList<BasicDBObject> andList = new ArrayList<>()
BasicDBList theMegaArray = new BasicDBList()
for (int i = 1; i <= 5; i++) {
String identifier = "categories.category" + i
String cleanIdentifier = '$' + identifier
//If the category does not exist, put in a blank category
theMegaArray.add(new BasicDBObject('$ifNull', Arrays.asList(cleanIdentifier, Collections.EMPTY_LIST)))
}
//merges all of the category arrays into 1
theProjections.put("allCategories", new BasicDBObject('$setUnion', theMegaArray))
orList.add(new BasicDBObject("allCategories", new BasicDBObject('$all', cats)))
andList.add(new BasicDBObject('$or', orList))
criteria.put('$and', andList)
}
pipeline.add(new BasicDBObject('$project', theProjections))
pipeline.add(new BasicDBObject('$match', criteria))
//and by default
iterable = collection.aggregate(pipeline)
的問題是,如果我想在貓搜索,我需要的投影是在管道第一但如果我想要文字,那麼我需要比賽首先在那裏。我有兩種方法可以做到嗎?
您不能像聚合管道的第一階段那樣運行「文本搜索」。造成這種情況的原因很簡單,因爲您需要索引,並且在第一階段之後的任何事情「可以」改變文檔的結構,並因此使索引的使用無效。 –
我在那裏看到'$ setUnion'。你知道你可以在這些數組的所有可能的字段名稱上指定文本索引。根據本質進行的文本搜索適用於所有要指定的字段,因此不需要聚合管道將它們合併。 –
我希望cats數組完全匹配類別對象中的內容。我相信,即使只匹配1個詞@NeilLunn,文本搜索也會帶來結果 – kulsoompatel