MongoDB query into an array of arrays

Question

I have the following schema into my DB:

{ name: 'AFG',
  documents: [
    { name: 'doc1',
      templates: [
        { name: 'templ1',
          lastModified: <Date>},
        ...]
    },
    ...]
}

I am trying to make a query to look for the template with name 'templ1'. If I find it, I have to compare the last modification date with another and update the value. If I don't find it, I have to push it into the array.

I have tried to do it with the following query:

Country.findOne({name : countrySelected, documents : {$elemMatch: {name: documentSelected}}, 'documents.templates' : {$elemMatch: {name: templateSelected}}}, function(err, templateFound){...}

But I get the following error:

MongoError: cannot use the part (documents of documents.templates) to traverse the element ({documents: [ { name: "Passport", templates: [] }, { name: "Visa", templates: [] }, { name: "Driver's Licence", templates: [] }, { name: "Id Card", templates: [] }, { name: "Other", templates: [] } ]})

Someone knows how can I do it? Thanks!!

Please check a similar question: http://stackoverflow.com/questions/10043965/how-to-get-a-specific-embedded-document-inside-a-mongodb-collection — Alexander Suvorov, Apr 18 '16 at 13:22

score 0 · Answer 1 · edited May 23 '17 at 11:59

You have to use the $in operator to search in arrays.

Country.findOne({
    name : countrySelected, 
    documents: {
        $elemMatch: {
            $and: [{
                name: {
                    $in: documentSelected //<-- must be array like ['doc1']
                }
            }, {
                'templates.name': {
                    $in: documentSelected //<-- must be array like ['tmpl1']
                 }
            }]
        }
    }
}, function(err, templateFound){
    //do something with err and templateFound
});

To update the LastModified date you need to update it in the callback function and save the document.

See this answer for nested array updates

MongoDB query into an array of arrays

1 Answers1