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🧾 MongoDB: JSON Schema Validation

📌 What is JSON Schema Validation?

MongoDB allows you to enforce a schema using $jsonSchema to ensure data consistency.

It validates documents before insertion or update, helping maintain clean and reliable data.

1️⃣ Creating a Collection with Name Validation

MongoDB Shell
NoSQL
Database
1db.createCollection("students", {
2  validator: {
3    $jsonSchema: {
4      required: ["name", "age"],
5      title: "Student Object Validation",
6      properties: {
7        name: {
8          bsonType: "string",
9          description: "Name must be a string and is required"
10        }
11      }
12    }
13  }
14});
Query Result
JSON Output
✅ A new collection "students" is created with validation enforcing that name must be a string.

2️⃣ Creating a Collection with Age Validation

MongoDB Shell
NoSQL
Database
1db.createCollection("students", {
2  validator: {
3    $jsonSchema: {
4      required: ["name", "age"],
5      title: "Student Object Validation",
6      properties: {
7        age: {
8          bsonType: "int",
9          minimum: 5,
10          maximum: 20,
11          description: "Age must be an integer between 5 and 20"
12        }
13      }
14    }
15  }
16});
Query Result
JSON Output
✅ "students" collection validates that 'age' must be an integer between 5 and 20.

3️⃣ Creating a Collection with Course Validation

MongoDB Shell
NoSQL
Database
1db.createCollection("students", {
2  validator: {
3    $jsonSchema: {
4      required: ["name", "age"],
5      title: "Student Object Validation",
6      properties: {
7        course: {
8          bsonType: "string",
9          enum: ["BCA", "BTECH", "BSC", "MCA", "MTECH"],
10          description: "Course must be one of: BCA, BTECH, BSC, MCA, MTECH"
11        }
12      }
13    }
14  }
15});
Query Result
JSON Output
✅ Enforces that 'course' field must match one of the predefined options.

4️⃣ Object Validation (Nested Objects)

MongoDB Shell
NoSQL
Database
1address: {
2  bsonType: "object",
3  required: ["street", "city", "zipCode"],
4  properties: {
5    street: {
6      bsonType: "string",
7      description: "Street must be a string and is required."
8    },
9    city: {
10      bsonType: "string",
11      description: "City must be a string and is required."
12    },
13    zipCode: {
14      bsonType: "int",
15      description: "Zip code must be an integer and is required."
16    }
17  }
18}
Query Result
JSON Output
✅ Validates nested 'address' object fields with types and required constraints.

5️⃣ Full Validation Example – Students Collection

MongoDB Shell
NoSQL
Database
1db.createCollection("students", {
2  validator: {
3    $jsonSchema: {
4      required: ["name", "age", "course"],
5      title: "Student Object Validation",
6      properties: {
7        name: {
8          bsonType: "string",
9          description: "Name must be a string and is required"
10        },
11        age: {
12          bsonType: "int",
13          minimum: 5,
14          maximum: 20,
15          description: "Age must be an integer between 5 and 20"
16        },
17        course: {
18          bsonType: "string",
19          enum: ["BCA", "BTECH", "BSC", "MCA", "MTECH"],
20          description: "Course must be one of the following: BCA, BTECH, BSC, MCA, MTECH"
21        }
22      }
23    }
24  }
25});
Query Result
JSON Output
✅ Creates a collection with full schema validation for 'name', 'age', and 'course' fields.

6️⃣ Valid Insert Example

MongoDB Shell
NoSQL
Database
1db.students.insertOne({
2  name: "Rajesh Rathwa",
3  age: 20,
4  course: "BCA"
5});
Query Result
JSON Output
{
  acknowledged: true,
  insertedId: ObjectId('67c07db7dd5d0f9807cb0ce3')
}

7️⃣ Invalid Insert – Age Exceeds Limit

MongoDB Shell
NoSQL
Database
1db.students.insertOne({
2  name: "Rajesh Rathwa",
3  age: 25,
4  course: "BCA"
5});
Query Result
JSON Output
❌ Error: Document failed validation – Age must be between 5 and 20.

8️⃣ Invalid Insert – Name Not a String

MongoDB Shell
NoSQL
Database
1db.students.insertOne({
2  name: 50,
3  age: 20,
4  course: "BCA"
5});
Query Result
JSON Output
❌ Error: Document failed validation – Name must be a string.

9️⃣ Modify Existing Collection Schema (collMod)

MongoDB Shell
NoSQL
Database
1db.runCommand({
2  collMod: "students",
3  validator: {
4    $jsonSchema: {
5      required: ["name", "age"],
6      properties: {
7        name: {
8          bsonType: "string",
9          description: "Name must be a string and is required"
10        }
11      }
12    }
13  }
14});
Query Result
JSON Output
✅ Schema for "students" collection successfully updated using collMod.

🔟 Create and Validate 'personal' Collection

MongoDB Shell
NoSQL
Database
1db.runCommand({
2  collMod: "personal",
3  validator: {
4    $jsonSchema: {
5      required: ["name", "age", "married", "dob", "weight", "kids", "address"],
6      properties: {
7        name: { bsonType: "string" },
8        age: { bsonType: "int", minimum: 20, maximum: 35 },
9        married: { bsonType: "bool" },
10        dob: { bsonType: "date" },
11        weight: { bsonType: "double" },
12        kids: { bsonType: "int" },
13        hobbies: { bsonType: "array", items: { bsonType: "string" } },
14        address: {
15          bsonType: "object",
16          required: ["street", "city", "zip"],
17          properties: {
18            street: { bsonType: "string" },
19            city: { bsonType: "string" },
20            zip: { bsonType: "int" }
21          }
22        }
23      }
24    }
25  }
26});
Query Result
JSON Output
✅ 'personal' collection updated with comprehensive validation rules including nested object and array checks.

1️⃣1️⃣ Valid Insert in 'personal' Collection

MongoDB Shell
NoSQL
Database
1db.personal.insertOne({
2  name: "Yash Hitesh",
3  age: 22,
4  married: true,
5  dob: ISODate("2001-10-01T07:30:00.000Z"),
6  weight: 61.22,
7  kids: 2,
8  hobbies: ["music", "travel"],
9  address: { street: "456 Main St", city: "Goa", zip: 10001 }
10});
Query Result
JSON Output
{
  acknowledged: true,
  insertedId: ObjectId('67c16f10ffc5a23fa2cb0ce2')
}

1️⃣2️⃣ Invalid Insert – Multiple Validation Errors

MongoDB Shell
NoSQL
Database
1db.personal.insertOne({
2  name: 23333,
3  age: 22,
4  married: "yes",
5  dob: ISODate("2001-10-01T07:30:00.000Z"),
6  weight: 61.22,
7  kids: 2,
8  hobbies: ["music", "travel"],
9  address: { street: "456 Main St", city: "Goa", zip: 10001 }
10});
Query Result
JSON Output
❌ MongoServerError: Document failed validation
{
  propertyName: "name",
  description: "Name must be a string and is required."
},
{
  propertyName: "married",
  description: "Married must be a boolean (true/false)."
}
Keep Going!MongoDB - Update & Replace Document