Question

What kind of database MongoDB is?

Answer

MongoDB is document oriented NOSQL database. Its stores its documents in form of BSON structured documents stored in collection.

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Question

Why should we use MongoDB instead of RDB?

Answer

Using or not using MongoDB depends on scope and requirements of app. We should use MongoDB when models need to be modified or extended on the fly and structure of models is not important.

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Question

Does MongoDB support foreign key constraints?

Answer

No.

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Question

Does MongoDB provide atomic operations?

Answer

Yes.

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Question

How does indexing work in MongoDB?

Answer

Indexes are applied to queries which results in read efficiency. If index is created and applied Mongo doesn’t scan every document in collection instead it will look up indexed results achieving read efficiency.

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Question

What factors must be kept in account before applying indexes in MongoDB?

Answer

Amount of memory available to system. Ratio of reads to writes. Frequency of query, index is applied to.

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Question

What makes indexedDB search fast?

Answer

Indexes are stored in RAM or are stored in sequential memory on disk, this makes this search lot fast such as covered query.

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Question

What is the maximum size of MongoDB document?

Answer

16 MB.

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Question

How can we use profiler in Mongo DB to achieve efficiency?

Answer

Profiler gives information about performance characteristics of each database operation. This information can be used to identify efficient queries and identifying indexes.

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Question

What is Aggregation in MongoDB?

Answer

In MongoDB aggregation is grouping values from multiple documents and running query on grouped data to find results.

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Question

How is Object ID composed in MongoDB?

Answer

3 bytes incremented counter. Client machine id. Time stamp. Client process id.

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Question

What sort of schema MongoDB database has?

Answer

MongoDB database has dynamic schema, this means there is no need to define structure for creating collections.

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Question

What is sharding in MongoDB?

Answer

Process of storing different data records across more machines is called sharding. This solution is useful in situation of handling more data records and efficient query.

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Question

How does MongoDB achieve concurrency?

Answer

MongoDB has read and write locks which grants many users read access at same time but do single write on DB at a time.

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Question

What are methods for bulk write in MongoDB?

Answer

Two ways are available here, serial and nonserial write. Serial write will write to DB in order, and if any write fail, all other operations will also stop. In non serial write, order of write is not consistent and execution won’t stop if any write fails.

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