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Mongodb compass sort desc12/30/2023 ![]() ![]() Now, imagine I want only to retrieve the fields title, and genre.ĭb.getCollection('movies').find().skip(10). Let´s see some examples if I want to display a list of movies ordered asc by year, and title I would use this SQL query: 1. Using MongoDB collections to select fields to displayĭoing a find on a collection does return all the fields of the item, so an SQL query that does a SELECT * translates into mongo as a plain find function, no need to specify anything else. Sorting in MOngoDB is quite easy, we only need to use the sort function passing a list of field we want to order by: 1 means order asc, and -1 order desc. We will be using the same movies collection we used on the post about how to filter string fields using LIKE style queries. You will not get any error.Following with the spirit of the last posts on how to query MongoDB from the perpective of an SQL developer, in this post will see how the concepts of select, top and order by translate into the MongoDB universe. In both cases if the keys specified exist on a document they are used, otherwise they aren't. You can just ask MongoDB for any set of keys (i.e the projection part of the query) or query on any set of keys. Though this is the case, most applications do maintain a schema for their collections and as said by Chris this is enforced by your application.Īs such you wouldn't have to worry about first fetching the available keys to make a query. With the use of aggregation expressions and syntax, you can project new fields or project existing fields with new values. So there can't really be a description of a collection, like the description of a table in the relational databases. Starting in MongoDB 4.4, db.collection.find () projection can accept aggregation expressions and syntax. MongoDB Compass acts as a GUI for MongoDB, allowing you to navigate through your databases, execute queries and perform various operations. So my question is : Is there any chance that 2 documents, A and B, A.id > B.id, but A.createdat < B.createdat. ![]() id is of course increasing, and the value of createdat is currentdate should be increasing. MongoDB being schema-less allows a single collection to have a documents with different fields. Get Started > Introduction If you’re looking for an easy way to visualize and understand your data, MongoDB Compass Community is a simple solution. 18 I have a document with a field id has type ObjectId, and a field createdat has type Date. So if you're looking for the schema in MongoDB, look towards your application for answers and not the database.Įssentially I am saying the exactly same thing as Shain :)ĪFAIK, there isn't a way and it is logical for it to be so. We don't have to worry about keeping the database tables/columns in-sync with the class structure. With MongoDB, if we had to change a particular model, we simply add, remove, or modify the fields in the class itself and it works right off the bat. In the former example, the fields are right there in front of our eyes. In the latter version with MySQL, the fields are being pulled from the database directly. Now after switching to MySQL, our classes look like this, class Consumer < ActiveRecord::Baseĭon't get fooled by the brevity of the classes. For instance, in our Rails application, these are two of the models we have in Mongo, class Consumer As long as you know that admins are not secretly logging into Mongo and making changes, and all access to the database is controller through some wrapper, the only place you should look at for the schema is your model classes. The database will shove in whatever it is given. Of course, there is a schema involved when dealing with schema-less databases like MongoDB, but the schema is dictated by the application, not the database. But having implemented the same model on both MongoDB and MySQL, I can clearly see the difference now. Unfortunately, we have switched back to MySQL after working with MongoDB because of my company's current infrastructure issues. ![]() This is my day 30 or something like that of playing around with MongoDB. ![]()
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