How do you update objects in a document’s array (nested updating)

by

For question #1, let’s break it into two parts. First, increment any document that has “items.item_name” equal to “my_item_two”. For this you’ll have to use the positional “$” operator. Something like:

 db.bar.update( {user_id : 123456 , "items.item_name" : "my_item_two" } , 
                {$inc : {"items.$.price" : 1} } , 
                false , 
                true);

Note that this will only increment the first matched subdocument in any array (so if you have another document in the array with “item_name” equal to “my_item_two”, it won’t get incremented). But this might be what you want.

The second part is trickier. We can push a new item to an array without a “my_item_two” as follows:

 db.bar.update( {user_id : 123456, "items.item_name" : {$ne : "my_item_two" }} , 
                {$addToSet : {"items" : {'item_name' : "my_item_two" , 'price' : 1 }} } ,
                false , 
                true);

For your question #2, the answer is easier. To increment the total and the price of item_three in any document that contains “my_item_three,” you can use the $inc operator on multiple fields at the same time. Something like:

db.bar.update( {"items.item_name" : {$ne : "my_item_three" }} ,
               {$inc : {total : 1 , "items.$.price" : 1}} ,
               false ,
               true);

More Related Contents:

  1. MEAN app vs. Mongo service local in Angular2
  2. Find objects between two dates MongoDB
  3. How to update the _id of one MongoDB Document?
  4. Conditional $sum in MongoDB
  5. mongoDB/mongoose: unique if not null
  6. MongoDB password with “@” in it
  7. MongoDB: How to query for records where field is null or not set?
  8. exclude fields in $lookup aggregation
  9. Mongo how to $lookup with DBRef
  10. Add some kind of row number to a mongodb aggregate command / pipeline
  11. How do you query for “is not null” in Mongo?
  12. MongoDB: exception in initAndListen: 20 Attempted to create a lock file on a read-only directory: /data/db, terminating
  13. MongoDB 3.2 authentication failed
  14. MongoDB ‘unable to find index for $geoNear query’
  15. MongoDB sort documents by array elements
  16. MongoDB won’t start after server crash
  17. Does Mongoose support the Mongodb `findAndModify` method?
  18. MongoDB Text Search AND multiple search words
  19. How does sorting with an index work in MongoDB?
  20. How to use dot in field name?
  21. How to get multiple document using array of MongoDb id?
  22. Docker: change folder where to store docker volumes
  23. How to organise a many to many relationship in MongoDB
  24. MongoDB : aggregation framework : $match between fields
  25. brew services. Cant start service. get “Bootstrap failed: 5: Input/output error”
  26. Map-Reduce performance in MongoDb 2.2, 2.4, and 2.6
  27. Unique IDs with mongodb
  28. MongoDB count() versus countDocuments()
  29. mongodb : Increasing max connections in mongodb
  30. Mongo $in operator performance

Leave a Comment