MongoDB

 

Introduction to MongoDB

MongoDB is a NoSQL database that stores the data in form of key-value pairs. It is an Open Source, Document Database which provides high performance and scalability along with data modeling and data management of huge sets of data in an enterprise application.

MongoDB also provides the feature of Auto-Scaling. Since, MongoDB is a cross-platform database and can be installed across different platforms like Windows, Linux, etc.

Brief History of MongoDB

MongoDB was developed by Eliot Horowitz and Dwight Merriman in the year 2007, when they experienced some scalability issues with the relational database while developing enterprise web applications at their company DoubleClick. According to Dwight Merriman, one of the developers of MongoDB, this name of the database was derived from the word humongous to support the idea of processing a large amount of data.

In 2009, MongoDB was made as an open-source project, while the company offered commercial support services. Many companies started using MongoDB for its amazing features. The New York Times newspaper used MongoDB to build a web-based application to submit the photos. In 2013, the company was officially named MongoDB Inc.

Document Database

A record in MongoDB is a document, which is a data structure composed of field and value pairs. MongoDB documents are similar to JSON objects. The values of fields may include other documents, arrays, and arrays of documents.

The advantages of using documents are:

• Documents (i.e. objects) correspond to native data types in many programming languages.
• Embedded documents and arrays reduce the need for expensive joins.
• The dynamic schema supports fluent polymorphism.

CRUD Operations With Examples

Objective: Teach a set of basic concepts in MongoDB and Git.

1.      Start MongoDB instance locally by issuing the following command inside the bin folder inside MongoDB installation directory.
 
 cd C:\ProgramFiles\MongoDB\Server\4.2\bin\
 
The above command will only work if you have C:\data\db folder created (assuming you have installed MongoDB in C: drive). Otherwise, you need to provide a data directory path by issuing the following command. The data directory is used by MongoDB to save all the files related to databases.
 
 mongod --dbpath [PATH_TO_DATA_DIRECTORY]
 
 
 
2.       Check MongoDB is working by connecting to the local instance using an IDE.Default port for MongoDB is 27017.
 
 
3.       Add the following document to the database sliit;
 
 { "name": "John",
"dateOfBirth": "1990-01-01T00:00:00Z",
"subjects": ["Application frameworks", "Computer architecture"]
 }
 
 
db.getCollection('Lab03_MongoDB').insertOne({
    "name" : "john",
    "name": "John",
    "dateOfBirth": "1990-01-01T00:00:00Z",
    "subjects": ["Application frameworks", "Computer Architecture"]
   
    })
 
 
● We always make sure to add dates in MongoDB as a UTC date since MongoDB by default deals with UTC timezone and format.
 
 
 
4.       Find the document by ‘name’.
 
db.getCollection('Lab03_MongoDB').find({
"name": "John"})
 
 
5.       Find the document by ‘_id’.
 
db.getCollection('Lab03_MongoDB').find({
"_id":ObjectId("604a2b5a9418916e7c143978")})
 
 
6.      Add ‘Distributed Computing’ to the subjects list.
 
db.getCollection('Lab03_MongoDB').update(
    {
        "name": "John"
    },
    {
        $push:{"subjects":"Distributed Computing"}
    })
 
 
7.      Add the following 2 documents to the same collection.
 
 {
"name": "Smith",
"dateOfBirth": "1990-01-15T00:00:00Z",
"subjects": ["Application frameworks", "Computer architecture"],
 "isActive": true
}
{
 "name": "Jane",
"dateOfBirth": "1990-02-15T00:00:00Z",
"subjects": ["Application frameworks", "Computer architecture"],
"isActive": false
}
 
 
 
db.getCollection('Lab03_MongoDB').insertMany([
{
   
"name": "Smith",
"dateOfBirth": "1990-01-15T00:00:00Z",
"subjects": ["Application frameworks", "Computer architecture"],
"isActive": true
},
{
"name": "Jane",
"dateOfBirth": "1990-02-15T00:00:00Z",
"subjects": ["Application frameworks", "Computer architecture"],
"isActive": false 
}
])
 
 
 
8.       Find the document with the name ‘Smith’ and isActive flag is true and add Distributed computing to subjects.
 
db.getCollection('Lab03_MongoDB').update(
{
 
"name": "Smith", 
"isActive" : {$eq:true}
},
{
    $push:{"subjects":"Distributed Computing"}
})
 

9.      Update the first document ‘isActive’ to false.
 
db.getCollection('Lab03_MongoDB').update(
{"name":"John"},
{$push:{"isActive":false}}
)
 

10.      Remove the first document created
db.getCollection('Lab03_MongoDB').deleteOne(
{"name":"John"}

)

 
11.   Find all data
 
db.getCollection('Lab03_MongoDB').find({ })