$ $放鬆推蒙戈

Question

我有一個教育Intitution文件，這似乎是這樣的：有一個String數組

{ name: ..., addresses: [...], courses: [ {name: ... , duration: ..., tags[...]} ] }

標籤。

我試圖找到其中有一些標籤內，比如一門課程：的Java，日食，支柱等等...

我的搜索方法是這樣的：

public BasicDBList coordinates(List tags){

BasicDBObject cmdBody = new BasicDBObject("aggregate", "EducationalInstitution"); 

    List<BasicDBObject> pipeline = new ArrayList<BasicDBObject>(); 

    BasicDBObject projectParams = new BasicDBObject(); 
    projectParams.put("name", 1); 
    projectParams.put("addresses.state", 1); 
    projectParams.put("addresses.locs", 1); 
    projectParams.put("courses", 1); 

    pipeline.add(new BasicDBObject("$project", projectParams)); 
    pipeline.add(new BasicDBObject("$unwind", "$addresses")); 
    pipeline.add(new BasicDBObject("$unwind", "$courses")); 
    pipeline.add(new BasicDBObject("$match", new BasicDBObject("courses.tags", new BasicDBObject("$all", tags)))); 

    cmdBody.put("pipeline", pipeline); 

    return (BasicDBList) getDatastore().getDB().command(cmdBody).get("result"); 
} 

當我運行此我得到類似的結果：

{ "_id" : ... , "name" : "X25" , "addresses" : { "state" : "DF" , "locs" : [ -15.806789 , -47.912779]} , "courses" : { "name" : "Microsoft Office Word 2010" , "duration" : 22 , "tags" : [...]}}

{ "_id" : ... , "name" : "X25" , "addresses" : { "state" : "DF" , "locs" : [ -15.806789 , -47.912779]} , "courses" : { "name" : "Microsoft Office Excel 2010" , "duration" : 18 , "tags" : [...]}} 

{ "_id" : ... , "name" : "X25" , "addresses" : { "state" : "DF" , "locs" : [ -15.806789 , -47.912779]} , "courses" : { "name" : "Microsoft Office PowerPoint 2010" , "duration" : 14 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "DF" , "locs" : [ -15.797209 , -47.883596]} , "courses" : { "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "DF" , "locs" : [ -15.797209 , -47.883596]} , "courses" : { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "DF" , "locs" : [ -15.797209 , -47.883596]} , "courses" : { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "PR" , "locs" : [ -25.431803 , -49.279532]} , "courses" : { "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "PR" , "locs" : [ -25.431803 , -49.279532]} , "courses" : { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "PR" , "locs" : [ -25.431803 , -49.279532]} , "courses" : { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "SP" , "locs" : [ -23.574942 , -46.71048]} , "courses" : { "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "SP" , "locs" : [ -23.574942 , -46.71048]} , "courses" : { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "SP" , "locs" : [ -23.574942 , -46.71048]} , "courses" : { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}} 

我想要的是我通過教育機構名稱和地址放鬆的小組課程。像這樣： { "_id" : ... , "name" : "X25" , "addresses" : { "state" : "DF" , "locs" : [ -15.806789 , -47.912779]} , "courses" : [{ "name" : "Microsoft Office Word 2010" , "duration" : 22 , "tags" : [...]}, { "name" : "Microsoft Office Excel 2010" , "duration" : 18 , "tags" : [...]}, { "name" : "Microsoft Office PowerPoint 2010" , "duration" : 14 , "tags" : [...]}]}

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "DF" , "locs" : [ -15.797209 , -47.883596]} , "courses" : [{ "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}, { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}, { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}]} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "PR" , "locs" : [ -25.431803 , -49.279532]} , "courses" : [{ "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}, { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}, { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}]} 

{ "_id" : ... , "name" : "ENG" , "addresses" : { "state" : "SP" , "locs" : [ -23.574942 , -46.71048]} , "courses" : [{ "name" : "MS Visio" , "duration" : 0 , "tags" : [...]}, { "name" : "Acrobat Professional" , "duration" : 12 , "tags" : [...]}, { "name" : "Framemaker" , "duration" : 0 , "tags" : [...]}]} 

我讀了關於$ push並試着實現，但是沒有成功。我嘗試在管道變量中添加BasicDBObject，並在cmdBody中追加該命令。

有人通過類似的問題嗎？

Answer 1

可以使用$推運營商，在外殼的$組管道運營商這樣一起：

db.t.aggregate([{$unwind:'$b'},{$unwind:'$c'},{$group:{_id:'$b',cs:{$push:'$c'}}}]) 

在JAVA像你的情況：

pipeline.add(new BasicDBObject("$group", new BasicDBObject(new BasicDBObject("_id", groupParams)).append("courses", new BasicDBObject("$push", "$courses")))); 

如果你是嚴格可能要使用與您所描述的相同的格式，您可以在最後包含一個$ project項目步驟，您可以重新格式化結果文檔。