Great job! Let’s go over a quick summary of what we’ve learned about deleting in MongoDB:
The
.deleteOne()method deletes a single document from a collection. It accepts a filter document specifying which document to delete as the first parameter.The
.deleteOne()method will only delete the first matching document in the collection.The
.deleteMany()method deletes all matching documents from a collection. It accepts a filter document specifying which document to delete as the first parameter.The
.replaceOne()method replaces an entire document from a collection. It takes in filtering criteria specifying the document to replace as the first parameter and a replacement document as the second one.The
.replaceOne()method will only replace the first matching document in the collection.Since
.replaceOne()replaces an entire document, only fields included in the second parameter will be present in the document after the operation executes.
In addition to the syntax we’ve learned throughout this lesson, MongoDB offers us other syntax and commands that can be useful when deleting or replacing documents:
- The
.findOneAndReplace()method is very similar to.replaceOne(). It replaces a document in a collection based on filter criteria, but instead of returning a document that acknowledges the operation, it returns either the original document or the replacement document. - The
.findOneAndDelete()method deletes a document, and returns the deleted document.
Congrats! You’ve learned a lot in the past exercises. Now you can use your knowledge and experiment with the provided collection!
Instructions
We have provided you with the listingsAndReviews collection. Before moving on, spend some time experimenting with writing queries, using the syntax you learned throughout this lesson. If you are up for a challenge, try any of the following tasks listed below. Remember to first connect to the restaurants database to access the listingsAndReviews collection. Good luck, and click Up Next when you are ready to move on!
Optional Tasks:
- Delete any restaurants that have received a
"C"grade via thegradesfield. After all, we have to keep our standards high! - Replace the cuisine of a restaurant of your choosing.
- Choose a restaurant with multiple grades of
"A". Replace the document, so it no longer has agradesfield but instead has a field namedtop_restaurantwith the value oftrue.