Description
Objective
In this lab,students learn how to update documents in a MongoDB database.
update(): This method updates one document by default. If you want to update all documents that match the criteria using this method, you need the option {multi:true}.
update(,,)The filter parameter specifies the criteria. For instance:{“_id”= 0}{} for updating all documentsThe update parameter specifies the changes that will be applied to a document.updateOne(): This method updates only the first document that matches the criteria.updateOne(,)updateMany(): This method updates all documents that match the criteria.updateMany(,)
Submission
For this lab, you should submit a file with the below exercises completed.
Your file should be called: L09–lastname-firstname(for example: L09-King-Les)
Getting Started
In this lab, you will use students.json dataset. Download students.json from Blackboard and store it in a folder named dataset.
Open your Windows command prompt and go the following directory where MongoDB is installed:
cd C:\Program Files\MongoDB\Server\4.2\bin
To run MongoDB, execute mongod
mongod
When MongoDB starts successfully, open another Windows command prompt and go the same bin directory:
cd C:\Program Files\MongoDB\Server\4.2\bin
and execute mongo
mongo
Or you execute a batch file to start up MongoDB.
You will import students.json to the college database. To import data, go to the bin directory:
cd C:\Program Files\MongoDB\Server\4.2\bin
Execute the following command:
mongoimport –dbcollege –collection students –file ..\dataset\students.json
To import the json file, provide the full path to the students.json. After executing the command, the data is imported to the college database. To make sure data is imported successfully, go to the MongoDB shell and execute the following command to see the imported documents:
show dbs
You should see the database college added to the list of your databases. To see the documents inside the database:
use college
db.students.find().forEach(printjson)
or
db.students.find().pretty()
Tasks
1. Write an update statement toadd new fields programand termto all documents in the students collection and set them to values “CPA” and 1.
2. Write an update statement to modify the value of the program field to “BTM” for all documents in the students collection.
3. Write an update statement to modify the value of the program field to “CPA” for the student named Jonie Raby.
Before executing an update statement or a delete statement, you can use the find() method with the update or delete criteria, to see how many documents will be affected.
Write the update statement in the box below.
How many documents are there with the value Jonie Raby for the name field? _______
How many documents were updated? ________
4. Write a query to show only the program field for the document that the value of the filed nameisJonie Raby.
5. Write an update statement to increase the value of the term field by 2 for documents with _id 20, 22, and 24.
6. Write an update statement to remove the term field from documents that the valueof the term filed is 3.
