All Basics of MongoDB

MongoDB is a rich open-source document-oriented and one of the widely recognised NoSQL database. It is written in C++ programming language.

Today, I wanted to share some of the basic stuff about MongoDB concepts and commands

Important Terms


Database is a physical container for collections. Each database gets its own set of files on the file system. A single MongoDB server typically has multiple databases.


Collection is a group of documents and is similar to an RDBMS table. A collection exists within a single database. Collections do not enforce a schema. Documents within a collection can have different fields.


A document is a set of key-value pairs. Documents have dynamic schema. Dynamic schema means that documents in the same collection do not need to have the same set of fields or structure, and common fields in a collection’s documents may hold different types of data.

Data Types

(Reference: tutorialsPoint)

MongoDB supports many datatypes such as:

  • String − This is the most commonly used datatype to store the data. String in MongoDB must be UTF-8 valid.

  • Integer − This type is used to store a numerical value. Integer can be 32 bit or 64 bit depending upon your server.

  • Boolean − This type is used to store a boolean (true/ false) value.

  • Double − This type is used to store floating point values.

  • Min/ Max keys − This type is used to compare a value against the lowest and highest BSON elements.

  • Arrays − This type is used to store arrays or list or multiple values into one key.

  • Timestamp − ctimestamp. This can be handy for recording when a document has been modified or added.

  • Object − This datatype is used for embedded documents.

  • Null − This type is used to store a Null value.

  • Symbol − This datatype is used identically to a string; however, it’s generally reserved for languages that use a specific symbol type.

  • Date − This datatype is used to store the current date or time in UNIX time format. You can specify your own date time by creating object of Date and passing day, month, year into it.

  • Object ID − This datatype is used to store the document’s ID.

  • Binary data − This datatype is used to store binary data.