Mongo Query on Subfields

Question

I have a document -

  {"_id" : ObjectId("51385d2308d427ce306f0100"),
  "aid" : "1",
  "studyId" : "study-1",
  "mediaType" : "microBlog",
  "text" : "bla bla",
  "sentences" : "bla bla",
  "status" : {
          "algo1" : "required",
          "algo2" : "required",
          "algo3" : "completed",
          "algo4" : "completed"
  },
  "priority" : "u"}

The status field has multiple sub-fields with different status values. Is it possible to create a query such that it returns all documents for which any of the status sub-field's value is "required"?

Something like db.foo.find({status : "required"}) which would give me all documents for which any of the sub-field has value "required"

ronasta · Accepted Answer · 2013-04-04 04:51:15Z

5

Another, more efficient, approach would be to implement your "status" sub-document as an array of "typed values", like this:

 {"_id" : ObjectId("51385d2308d427ce306f0100"),
  "aid" : "1",
  "studyId" : "study-1",
  "mediaType" : "microBlog",
  "text" : "bla bla",
  "sentences" : "bla bla",
  "status" : [
          { type: "algo1", value: "required" },
          { type: "algo2", value: "required" },
          { type: "algo3", value: "completed" },
          { type: "algo4", value: "completed" }
  ],
  "priority" : "u"}

This would allow you to find all the documents, for which any of the sub-field has value "required", with this query:

db.foo.find({"status.value":"required"})

Defining an index on this sub-field would speed up the query:

db.foo.ensureIndex({"status.value":1})

answered Apr 4, 2013 at 4:51

ronasta

2,5691 gold badge17 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Community · Accepted Answer · 2017-05-23 12:02:32Z

0

u could search via db.foo.find({ 'status.algo1' : 'required' }) or db.foo.find({ 'status.algo2' : 'required' }), but it's probably not possible to filter by regex keys, see also this post: https://stackoverflow.com/a/7290728/654952

edited May 23, 2017 at 12:02

CommunityBot

11 silver badge

answered Mar 7, 2013 at 11:09

yuwang

87611 silver badges24 bronze badges

1 Comment

KonceptGeek Over a year ago

Yes, I would need to use or conditions for each status.algo as what I require is not possible in Mongo.

ronasta · Accepted Answer · 2013-03-22 17:23:48Z

0

you could use mapReduce() where the map() function would contain something like:

// loop all key/value pairs in status without knowing its key
for ( item in this.status ) {
    // if value is required: emit the data and break the loop
    if ( this.status[item] == "required" ) {
        emit( ... )
        break;
    }
}

does this help ?

Cheers

Ronald

answered Mar 22, 2013 at 17:23

ronasta

2,5691 gold badge17 silver badges8 bronze badges

Collectives™ on Stack Overflow

Mongo Query on Subfields

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related