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Time to Code!

Now that we've done an overview of CRUD operations with Spring Data MongoDB, it's time to implement what we've learned. Everything you need to get coding is available in the previous sections. Once you think you have everything implemented, run the command and see if everything runs as expected.

Create​

In Create.java, see if you can implement the following methods:

  1. Save grade1 to your MongoDB database.
  2. Save the list of grades, grades to your database.

To test, run;

mvn spring-boot:run -Dspring-boot.run.arguments=create

Read​

In Read.java, see if you can implement the following methods:

  1. Find the first matching grade by student ID
  2. Find all grades with student IDs greater than or equal to 10000
  3. Find all grades by student ID and limit by class ID

To test, run;

mvn spring-boot:run -Dspring-boot.run.arguments=read

Update​

In Update.java, see if you can implement the following methods:

  1. Update a Document by Adding a Comment: Find a document by studentId and add a comment to it.
  2. Upsert a Document: Find a document by studentId and classId. If the document exists, update it by adding a new score. If it doesn't exist, create a new document with the provided details.
  3. Update Multiple Documents: Find all documents where studentId is greater than or equal to 10001, and update them.
  4. Find and Update a Document: Find a document by studentId, update it, and save the changes.

To test, run;

mvn spring-boot:run -Dspring-boot.run.arguments=update

Delete​

In Delete.java, implement the following methods to practice deleting documents in MongoDB:

  1. Delete a Single Document: Delete a grade it if it exists.
  2. Find and Delete a Document: Find a document with student id of 10002 by studentId, then delete it.
  3. Delete Multiple Documents: Find all documents where studentId is greater than or equal to 10000, and delete them.

To test, run;

mvn spring-boot:run -Dspring-boot.run.arguments=delete

Mapping POJOs​

Lastly, let's map a POJO to our Document. In MappingPOJO.java, create a grade called newGrade that has a unique ObjectId, a studentId of 10003 (decimal), a classId of 10 (decimal).

Also, when creating the new grade, add a score for a homework with a score of 50 (decimal).

To test, run;

mvn spring-boot:run -Dspring-boot.run.arguments=mapping