Top 10 MongoDB interview questions and answers for 2022

A collection is a collection of documents. If a document is MongoDB's equivalent of a row in a relational database, then a collection is MongoDB's equivalent of a table. Collections contain dynamic schemas. This means that the papers contained within a single collection might be of any shape. It's worth noting that the values in the previous documents are not just of different types (string and integer), but they frequently have entirely different keys. In MongoDB, any document can be contributed to any collection.

Sharding is the process of storing data records across many devices. It is a MongoDB strategy to meet data growth demands. It refers to the horizontal division of material in a database or search engine. Each partition is known as a shard or database shard.

The practice of synchronizing data across several servers is known as replication. Replication protects the database against the loss of a single server. With several copies of data on separate database servers, replication in MongoDB provides redundancy and boosts data availability.

While developing a schema, one must consider the following:

Create your schema according to user needs. If you use many objects together, combine them into a single document. Separate them if necessary. In the schema, perform sophisticated aggregation.

Objectld is composed of the following:

Timestamp Client machine ID Client process ID 3 byte incremented counter

Indexes are special structures in MongoDB that hold a subset of the data set in an easy-to-search format. The index maintains the value of a given field or collection of fields, ordered by the value of the field provided in the index.

MongoDB officially supports the following languages: C, C++, C#, Java, Node.js, Perl, PHP, Python, Ruby, Scala, Go, and Erlang. We can use MongoDB with any of the languages mentioned above. There are several other community-supported drivers available, but MongoDB provides the ones described above.

There are two types of data models in MongoDB. They are embedded and normalized data models. The structure of documents has an impact on data modeling. In MongoDB, related data can be incorporated into a single document structure (embedded data model). The relationship between data is stored through references from one document to another. It's known as the normalized data model.

MongoDB includes a database profiler that displays information about the performance of each database activity. You can use this profiler to discover queries (and write operations) that are taking longer than they should and use that information to determine when an index is required.

Replication is the technique of synchronizing data across many servers. It provides continuity and boosts data efficiency by storing multiple copies of data on different database servers. Replication safeguards the database against the loss of a single server.