$ unwind $ push Mongo

时间：2013-08-26 00:26:45

标签： java mongodb mongodb-java

我有一份教育机构文件，如下所示：

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

标签有一个String数组。

我正在尝试找到一个内部有一些标签的课程，例如： java ， eclipse ， struts 等...... < / p>

我的搜索方法如下：

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");
}

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"); }

当我运行时，我收到的结果如下：

{ "_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" : [...]}}

我想要的是按照教育机构名称和地址放松的小组课程。像这样： { "_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" : [...]}}

{ "_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" : [...]}]}

我读到了关于$ push和尝试实现但是没有成功。我尝试在管道变量中添加BasicDBObject并在cmdBody中附加命令。

有人为同样的问题通过了吗？

1 个答案:

答案 0 :(得分：1)

您可以在shell中使用$ push运算符和$ group管道运算符：

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

在JAVA的情况下，例如：

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

如果您严格使用与您描述的格式相同的格式，则最后可以包含$ project步骤，您可以重新格式化结果文档。

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