From the course: MongoDB Node.js Developer Associate Cert Prep

MongoDB CRUD operations: Modifying query results review

From the course: MongoDB Node.js Developer Associate Cert Prep

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MongoDB CRUD operations: Modifying query results review

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- In this unit, we learned to modify query results with MongoDB. We first saw how to return query results in a specified order using the cursor.sort() method. The sort method takes a sort document parameter that defines the sort order of the results set. We also saw how to constrain the number of results using the cursor.limit() method. The limit method takes an argument for the maximum number of documents to return. Remember that limiting results can enhance the performance of your application by avoiding unnecessary data processing. We then practiced returning selected fields from a query using projection. We saw how to specify fields to return by adding a projection document as a second parameter in calls to the .find() method. We now know that inclusion and exclusion statements can't be combined in most projections, with the exception of the _id field. We can choose to exclude the _id field in any projection, including when we are explicitly including other fields. Finally, we learned to count the number of documents matching a query using the db.collection.countDocuments() method. The countDocuments method accepts two parameters, a required query document, and an options document. Now that you've learned how to modify query results in the MongoDB shell, you might want to learn how to carry out some of these operations in your programming language of choice. Feel free to use any one of MongoDB's client drivers. Review MongoDB's documentation on CRUD operations in that specific language driver, or check out one of Mongo DB's drivers courses for more information. Congratulations on completing this unit on modifying query results with MongoDB.

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