在MongoDB中更新嵌入式数组

Question

I am trying to update the embedded array document in collection structure is

        {
            id: 1,
            fields:[ 
                { 
                   "lang" : "eng","embeddedArray" : ["A","B","C"]
                },
                {
                   "lang" : "abcd","embeddedArray" :["A","D","E"]
                }]
        }

I want to update A with a in embeddedArray i try to update using this query but it is updating the entire array with 'a' instead of ['a','B','C']

db.collectionName.update({"fields.embeddedArray" : 'A'}, {"$set" : {"fields.$.embeddedArray" : "a"}});

Is their any way to update without loosing the other elements in array ?

Answer 1

Please check the below query :

db.collectionName.find({"fields":{$elemMatch:
                       {"lang":"A"}}}).forEach(function(doc){
                         var fields = doc.fields;
                         var i,k;
                        for( i=0; i<fields.length; i++ )
                          {
                       k = fields[i].embeddedArray.indexOf("A");
                       fields[i].embeddedArray.splice(k,1,"a");
                          }
 db.collectionName.update({ _id: doc._id},{$set:{"fields": fields}});
});