ObjectId
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What is ObjectId?
ObjectId is MongoDB's default primary key type, consisting of a 12-byte identifier that includes timestamp, machine identifier, process ID, and counter components. It ensures uniqueness across distributed systems and provides automatic indexing. ObjectIds are automatically generated when documents are inserted without an explicit _id field, enabling efficient sorting by creation time and guaranteed uniqueness across collections.
Free resources to learn ObjectId
- Official docsObjectId
- ArticleUsage of ObjectId () in MongoDB with Examples
More in stage 3: Collections & Methods
- Collections & Methods
- Counting Documents
- insert() and relevant
- find() and relevant
- update() and relevant
- delete() and relevant
- bulkWrite() and relevant
- validate()
- BSON vs JSON
- Embedded Objects & Arrays
- Double
- String
- Array
- Object
- Binary Data
- Undefined
- Boolean
- Date
- Null
- Regular Expression
- JavaScript
- Symbol
- Int64 / Long
- Int32/Int
- Timestamp
- Decimal128
- Min Key
- Max Key
ObjectId: common questions
Can I learn ObjectId in Hindi?
This lesson is written in English. Once you sign in, open it in the interactive course and ask the AI tutor to explain ObjectId in Hindi or Hinglish. The tutor answers from this lesson’s own text, so it stays on the syllabus, and it runs on your own Google, OpenAI or Anthropic key.
Is this ObjectId tutorial for beginners?
It is lesson 24 of 106 in the free MongoDB roadmap, in stage 3, Collections & Methods. If you are new to MongoDB, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.