MongoDB is NoSQL data base used to store a high volume document. In this you will learn different array update operations. The following modifiers are used to update document' array. mongoDb is open sourced data based used for document. You can store up to 16GB data in a document. It is written in C++. You should have basic knowledge of database, editor and executions of programs. And as least you should know about RDMS concept as you are going to study high level database. Database in document

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... is known as collection. which is equal o a relation in RDBMS. Unlike RDBMS it's has no predefined schema. The schema in mongodb is dynamic. You can insert different key set in another document as well. Here is _id key which is by default key and work as a primary key in document. As schema is dynamic but you should save same type of document in a collection.