I have
{ "_id" : ObjectId("5a25af80d2c4dd065991dccc"), "username" : "abc@gmail.com", "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy", "role" : "Admin", "__v" : 0, "list" : [ { "name" : "We", "arr" : [ "5a26d554677475818a795f75", "5a395bb0976d5304c07f7dd4" ] }, { "name" : "sandeep", "arr" : [ "5a26d554677475818a795f75" ] } ] }
I want to add an element inside list.arr where name = 'we' and add only if the element does not exist
how do i perform this query.
if i properly understood you question,you want to match name field with we key,and update arr only if it exists ?, you have to use elemMatch, in other to get the right document
db.test.update({ list: { $elemMatch: { name: "We" , arr: { $nin: [ "valuette" ] }} } }, { $push: { "list.$.arr": "valuette" } } );
the $ in "list.$.arr" matches the specified index that matches name field with we value
update: to answer OP question
Intial database structure
> db.collection.find().pretty() { "_id" : ObjectId("5a25af80d2c4dd065991dccc"), "username" : "abc@gmail.com", "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy", "role" : "Admin", "__v" : 0, "list" : [ { "name" : "We", "arr" : [ "5a26d554677475818a795f75", "5a395bb0976d5304c07f7dd4" ] }, { "name" : "sandeep", "arr" : [ "5a26d554677475818a795f75" ] } ] }
Query executed
> db.collection.update({ list: { $elemMatch: { name: "We" , arr: {$nin: ["55555555555555555"]} } } }, { $push: { "list.$.arr": "55555555555555555" } } ) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
New database structure
> db.collection.find().pretty() { "_id" : ObjectId("5a25af80d2c4dd065991dccc"), "username" : "abc@gmail.com", "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy", "role" : "Admin", "__v" : 0, "list" : [ { "name" : "We", "arr" : [ "5a26d554677475818a795f75", "5a395bb0976d5304c07f7dd4", "55555555555555555" ] }, { "name" : "sandeep", "arr" : [ "5a26d554677475818a795f75" ] } ] }
Again same query Executed
> db.collection.update({ list: { $elemMatch: { name: "We" , arr: {$nin: ["55555555555555555"]} } } }, { $push: { "list.$.arr": "55555555555555555" } } ) WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 })
Checking the database structure again
> db.collection.find().pretty() { "_id" : ObjectId("5a25af80d2c4dd065991dccc"), "username" : "abc@gmail.com", "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy", "role" : "Admin", "__v" : 0, "list" : [ { "name" : "We", "arr" : [ "5a26d554677475818a795f75", "5a395bb0976d5304c07f7dd4", "55555555555555555" ] }, { "name" : "sandeep", "arr" : [ "5a26d554677475818a795f75" ] } ] }
No changes Found
By using this nested query I solved this problem. I'm doing it with Node JS
router.post('/prevList', (req, res) => { User.update({'_id':req.user.id, list: { $elemMatch: { name: req.body.name } } },{ $addToSet: { "list.$.arr": {$each: req.body.arr} } },function(err,data) { console.log(data); res.send(data) }); });
Here
req.body: {name:'we',arr:["5a395bb0976d5304c07f7dd4"]}
and req.user.id is the auth id.
Hope this helps you all too.
