Mongodb Installation

Install MongoDB on Windows

 

Download from http://www.mongodb.org/downloads  

Start Server:

Go to C:\Windows\System32\cmd.exe

Open cmd

In the command prompt, execute the command mongo or mongo.exe

Connect to MongoDB

 Once you have installed Compass and the program is running, an initial connection dialog appears:

 

In MongoDB, the first basic step is to have a database and collection in place. The database is used to store all of the collections, and the collection in turn is used to store all of the documents. The documents in turn will contain the relevant Field Name and Field values.

Creating a database using “use” command

 

1. The first part of the command is the "insert statement" which is the statement used to insert a document into the collection.
2. The second part of the statement is to add the Field name and the Field value, in other words, what is the document in the collection going to contain. 

printing in JSON format 

 

Why do we need the ObjectId field? Well, MongoDB uses this as the primary key for the collection so that each document can be uniquely identified in the collection.


Search records:{EmployeeName : "Devayan"}

MongoDB Cursor 

When the db.collection.find () function is used to search for documents in the collection, the result returns a pointer to the collection of documents returned which is called a cursor. 

MongoDB Query Modifications using limit(), sort()

1. Limits

This modifier is used to limit the number of documents which are returned in the result set for a query.

Example:

db.EmployeeDB.find().limit(2).forEach(printjson);

2. Orders

One can specify the order of documents to be returned based on ascending or descending order of any key in the collection.

Example:

db.EmployeeDB.find().sort({Employeeid:-1}).forEach(printjson)

Here the -1 indicates that we want to return the documents based on the descending order of Employee id.

MongoDB provides the count() function to the count of documents in a collection as per the query fired.

Example:

db.EmployeeDB.count()

In MongoDB, the db.collection.remove () method is used to remove documents from a collection.

Eample:

db.EmployeeDB.remove({Employeeid:'4'})

MongoDB provides the update() command to update the documents of a collection.

Example:

db.EmployeeDB.update({Employeeid:'3'},{$set:{"EmployeeName":"Anand"}})

Note:Please make sure that column name is correct,otherwise new column will be created.

Example:

db.EmployeeDB.update
    (
        {
            Employeeid : '2'
        },
        {
            $set :
            {
                "EmployeeName" : "NewMartin",
                  "Employeeid" : 22
               
            }
        }
    )

Start Mongo Server

C:\Windows\System32\cmd.exe > mongod

Open mongo shell

mongo

-------------------

Show created databases

show dbs

--------------------

Show collections

use Student

show collections

------------------------

Create user with role as userAdminAnyDatabase who can access any database

db.createUser(

{    user: "mongodb",

    pwd: "mongodb",

    roles:[{role: "userAdminAnyDatabase" , db:"admin"}]})

--------------------------------------  

create database Student

-------------------------------

//Display Records

db.StudentRecord.find().forEach(printjson)