Introduction To MongoDB

 

What is MongoDB?

MongoDB is a NoSQL document-oriented database. MongoDB is written by using C++ language. NoSQL databases are much different than relational databases. In a real database, you have to map out everything. You need to figure out the exact schema what table you use and what field you use and all that stuff. But with NoSQL, there is not like that. You should plan out the structure of your database and your collections. But you don’t have to do any free structuring before you build your application. An advantage is MongoDB is easy to scale. MongoDB uses documents containing key-value pairs to store data. A collection is a group of MongoDB documents. MongoDB uses collections instead of tables and uses documents instead of rows and uses fields instead of columns.

 

MongoDB Syntax

MongoDB uses use database_name syntax to create a database

 

Create a collection

Collections hold documents or records.

·       db.createCollection(name, option) syntax is used to create a collection

Student is the name of the collection and option is a document that use to specify configuration of the collection.

·       CreateCollection(name) syntax without option

 

Insert a document

·       db.faculty.insert() syntax is used to insert documents. Faculty is the collection name of that command.

In The above example shows how a document is stored in a MongoDB collection.

Note: You can add fields whatever you want to a document in a collection, even other documents in that collection does not have that field.

 

Get a document

·       db.getCollection(“faculty”).find() or db.faculty.find() syntax is used to retrieve data from a collection called faculty.

 

Update a document (add a new field to a document)

·       db.faculty.update({name:"Smith"},{$set:{gender:"male"}}) syntax is used to add new field to the faculty document.

 

Remove  a document

·       db.faculty.remove({name:"Smith"}) syntax is used to remove a document from the faculty collection.