SQL vs MongoDB CRUD Assignment Solution with Full Code Example (Student Database)

Here's the complete solution for the CRUD mini-assignment from Part 6 — in both SQL and MongoDB (NoSQL).

We’ll assume you're working with a student named "Nitin Joshi", and your task was to:

1. Add the student

2. Include marks

3. Read/display their data

4. Update their class and one of the marks

5. Delete their record

---

✅ SQL Solution

⚙️ Step 1: Insert into Students Table

INSERT INTO Students (StudentID, Name, Class)
VALUES (3, 'Nitin Joshi', '10A');

⚙️ Step 2: Insert into Marks Table (Assuming it's a separate table)

INSERT INTO Marks (MarkID, StudentID, Subject, Score)
VALUES
  (201, 3, 'English', 87),
  (202, 3, 'Science', 91);

---

⚙️ Step 3: Read Nitin's Full Profile (Using JOIN)

SELECT Students.Name, Students.Class, Marks.Subject, Marks.Score
FROM Students
JOIN Marks ON Students.StudentID = Marks.StudentID
WHERE Students.StudentID = 3;

---

⚙️ Step 4: Update Nitin’s Class and English Score

UPDATE Students SET Class = '10B' WHERE StudentID = 3;

UPDATE Marks
SET Score = 90
WHERE StudentID = 3 AND Subject = 'English';

---

⚙️ Step 5: Delete Nitin’s Records

DELETE FROM Marks WHERE StudentID = 3;
DELETE FROM Students WHERE StudentID = 3;

---

✅ MongoDB Solution

⚙️ Step 1: Insert Student with Marks

db.students.insertOne({
  student_id: 3,
  name: "Nitin Joshi",
  class: "10A",
  marks: [
    { subject: "English", score: 87 },
    { subject: "Science", score: 91 }
  ]
});

---

⚙️ Step 2: Read Student Document

db.students.findOne({ student_id: 3 });

---

⚙️ Step 3: Update Class and English Score

A. Update Class

db.students.updateOne(
  { student_id: 3 },
  { $set: { class: "10B" } }
);

B. Update English Score
Use $set with positional operator $ to target the right array element:

db.students.updateOne(
  { student_id: 3, "marks.subject": "English" },
  { $set: { "marks.$.score": 90 } }
);

---

⚙️ Step 4: Delete Student

db.students.deleteOne({ student_id: 3 });

---

🎯 Key Learnings

Operation	SQL	MongoDB
Related Data	JOIN across tables	Embedded in documents
Update nested data	Table-specific updates	Use positional operator ($)
Delete	Requires foreign key cleanup	Simple deleteOne()

---

🧠 Which database did you find easier — SQL or MongoDB? Comment below with your choice and why!

📌 Try modifying this example with your own student data and share your version!

← previous Next →