You can query embedded documents, just qualify the name. Now, this will return all Authors that have books that match your query. If Author is defined as having many :books (and book is an embedded::document) @authors_with_sewid = Author.where(“books.name” => “sewid”).all You’d then need to iterate over the authors and extract the books.
Try the following in the shell, it will iterate each item within a collection and try to match each document based on ID. Say we have 2 collections db.col1 and db.col2: > db.col1.find() { “_id” : 1, “item” : 1 } { “_id” : 2, “item” : 2 } { “_id” : 3, “item” : … Read more
exit from mongoshell with quit() and try to run command in regular command prompt, it will work
Not in “mongoose” specifically, or at least not yet as of writing. The MongoDB shell as of the 2.6 release actually uses the “Bulk operations API” “under the hood” as it were for all of the general helper methods. In it’s implementation, it tries to do this first, and if an older version server is … Read more
There is no explicit support for that, no. But you should be able to configure that just fine via the uri parameter. We’ve actually updated the documentation recently.
in my case most ids will be generated within a large number of mobile clients, not within a limited set of servers. I wonder if in this case, there is a justified concern. That sounds like very bad architecture to me. Are you using a two-tier architecture? Why would the mobile clients have direct access … Read more
Dbref in my opinion should be avoided when work with mongodb, at least if you work with big systems that require scalability. As i know all drivers make additional request to load DBRef, so it’s not ‘join‘ within database, it is very expensive. Is there a way to reference other documents without having the somewhat … Read more
Nothing wrong with what you are basically attempting, but perhaps the only clarification here is the common misconception that you need operators like $nin or $in when querying an array. Also you really need to do here is a basic inequality match with $ne: Person.find({ “groups”: { “$ne”: group._id } }) The “array” operators are … Read more
If you specified the correct port and still not able to connect to mongodb running in docker (like me), make sure you are using the service name (or container name) in your connection URL, e.g. mongodb://mongodb_service:27017/mydb, which is defined in your docker-compose.yml : services: mongodb_service: image: mongo I was using the hostname value and that’s … Read more
Inspired by this example on mongo’s website. GENERATE DUMMY DATA: > db.stack.insert({a:1,b:1,c:1,active:1}) > db.stack.insert({a:1,b:1,c:2,active:0}) > db.stack.insert({a:1,b:2,c:3,active:1}) > db.stack.insert({a:1,b:2,c:2,active:0}) > db.stack.insert({a:2,b:1,c:3,active:1}) > db.stack.insert({a:2,b:1,c:10,active:1}) > db.stack.insert({a:2,b:2,c:10,active:0}) > db.stack.insert({a:2,b:2,c:5,active:1}) MONGO QUERY: > db.stack.aggregate( … {$match:{active:1}}, … {$group:{_id:{a:”$a”, b:”$b”}, csum:{$sum:”$c”}}}, … {$sort:{“_id.a”:1}}) RESULT: {“result” : [ {“_id” : {“a” : 1,”b” : 2},”csum” : 3}, {“_id” : {“a” : … Read more