MongoDB Find an element in an array (subdocument)

Question

I am trying to update an array field in an subdocument array in my collection. My collection looks like this:

{
 _id:"1",
 employees:[{ eid:"2",
              ename:"test",
              is_user:true
             },
             { eid:"3",
              ename:"test2",
              is_user:true
             }
           ]
}

I am trying to update the is_user status and am trying it the following way:

db.users.update({_id:"1","employees.eid":"2"},{$set:"employees.$.is_user":true},true);

I also tried :

db.users.update({_id:"1","employees.$.eid":"2"},{$set:"employees.$.is_user":true},true);

But when I run a find, for the query:

db.users.find({_id:"1","employees.eid":"2"});

it still gives me nothing. Can anybody help me on this ? Thank you..

Pablo Fernandez heelhook · Accepted Answer · 2012-11-12 00:52:31Z

5

That does work.

> db.test.insert({_id:"1", employees:[{ eid:"2", ename:"test", is_user:true }, { eid:"3", ename:"test2", is_user:true } ] })
> db.test.find({_id:"1","employees.eid":"2"});
{ "_id" : "1", "employees" : [  {   "eid" : "2",    "ename" : "test",  "is_user" : true },  {   "eid" : "3",    "ename" : "test2", "is_user" : true } ] }

For the $ operator you want to use it like:

> db.test.insert({_id:"1", employees:[{ eid:"2", ename:"test", is_user:false }, { eid:"3", ename:"test2", is_user:false } ] })
> db.test.find({_id:"1", "employees.eid":"2", "employees.is_user": true});
> db.test.update({_id:"1", "employees.eid":"2"}, {$set: {"employees.$.is_user": true}});
> db.test.find({_id:"1", "employees.eid":"2", "employees.is_user": true});
{ "_id" : "1", "employees" : [  {   "eid" : "2",    "ename" : "test",   "is_user" : true },     {   "eid" : "3",    "ename" : "test2",  "is_user" : false } ] }

Notice how the insert of is_user is set to false on both objects in the array and after the update the matching object is updated from false to true, is that what you are looking for?

edited Nov 12, 2012 at 0:52

answered Nov 12, 2012 at 0:33

Pablo Fernandez heelhook

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5 Comments

sharath Over a year ago

yes.. it does, but I wanna just get the array element I wanna update. When I run an update, the is_user field is not updated.

sharath Over a year ago

Is there a typo on one of the queries u typed, because I dont see an update query.

sharath Over a year ago

Even this doesnt work for me :( db.users.update({_id:"1","employees.eid":"2"},{$set:{"employees.$.is_user":true}},true);

Pablo Fernandez heelhook Over a year ago

Sorry, missed the update query, you are right, just copied it.

sharath Over a year ago

Pretty much what my update was doing.. But got it working now.. Thanks a lot dude.. I was trying with the positional operator on the 'query' part, but guess thats not rt.. Thanks a ton again :) People like you, get us going :) Thanks for those super quick replies

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