| Data Type | Purpose | Example |
|---|
| ObjectId | Unique ID for each document | ObjectId("64b9d7f3e4b0c123456789ab") |
| String | Store text | "name": "John" |
| Integer | Store whole numbers | "age": 25 |
| Double | Store decimal numbers | "price": 99.99 |
| Boolean | Store true or false | "isActive": true |
| Date | Store date and time | "createdAt": ISODate("2026-07-30") |
| Array | Store multiple values | "skills": ["Java", "MongoDB"] |
| Object (Embedded Document) | Store nested data | "address": { "city": "Delhi" } |
| Null | Represent no value | "phone": null |
{
"_id": ObjectId("64b9d7f3e4b0c123456789ab"),
"name": "Alice",
"age": 22,
"salary": 45000.50,
"isActive": true,
"joiningDate": ISODate("2026-07-30"),
"skills": ["Java", "MongoDB"],
"address": {
"city": "Mumbai",
"state": "Maharashtra"
},
"phone": null
}