How to CRUD (Create,Read,Update and Delete) & create an embedded document and Alter a key in embedded doument in mongoDB

/*Create a User Database Named PersonDB */

MongoDB Enterprise > use personDB
switched to db personDB

/*Check you are in which database */
MongoDB Enterprise > db
personDB

/*Create a Post Variable */
MongoDB Enterprise > post={"name":"Rakesh","friend":477,"enemy":2}

{ "name" : "Rakesh", "friend" : 477, "enemy" : 2 }
/* Create Person table and Insert data into that table using  post variable*/

MongoDB Enterprise > db.Person.insert(post)
WriteResult({ "nInserted" : 1 })
MongoDB Enterprise > db.person.read()

MongoDB Enterprise > db.person.find()
-- Value did not return because MongoDB is highly case sensitive

/* search record inserted or not */
MongoDB Enterprise > db.Person.find()
{ "_id" : ObjectId("5896e738afd337d2cb8debce"), "name" : "Rakesh", "friend" : 477, "enemy" : 2 }

/* Now we need to add Address column as a embedded document using post variable */

-- The First step is to modify the variable post and add a "comment" key:

MongoDB Enterprise > post.address={"street":"L B S Nagar","House No":203,"Apartment":"Cansa Park"}

MongoDB Enterprise > db.Person.update({"name":"Rakesh"},post)
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
MongoDB Enterprise > db.Person.find()
{ "_id" : ObjectId("5896e738afd337d2cb8debce"), "name" : "Rakesh", "friend" : 477, "enemy" : 2, "address" : { "street" : "L B S XXXX", "House No" : 1234, "Apartment" : "Salnsa XXX" } }

MongoDB Enterprise > db.Person.findone()
2017-02-05T14:44:09.204+0530 E QUERY    [thread1] TypeError: db.Person.findone is not a function :
@(shell):1:1

MongoDB Enterprise > db.Person.findOne()
{
        "_id" : ObjectId("5896e738afd337d2cb8debce"),
        "name" : "Rakesh",
        "friend" : 477,
        "enemy" : 2,
        "address" : {
                "street" : "L B S XXXX",
                "House No" : 1234,
                "Apartment" : "Salnsa XXX"
        }
}


/* Now we have to add a key Pin in address to Address key */

MongoDB Enterprise > post.address={"street":"L B S XXXX","House No":1234,"Apartment":"Salnsa XXX","pin":560017}

{
        "street" : "L B S XXXX",
        "House No" : 1234,
        "Apartment" : "Salnsa XXX",
        "pin" : 560017
}

MongoDB Enterprise > db.Person.update({"name":"Rakesh"},post)

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

MongoDB Enterprise > db.Person.findOne()
{
        "_id" : ObjectId("5896e738afd337d2cb8debce"),
        "name" : "Rakesh",
        "friend" : 477,
        "enemy" : 2,
        "address" : {
                "street" : "L B S XXXX",
                "House No" : 1234,
                "Apartment" : "Salnsa XXX",
                "pin" : 560017
        }
}
Removing  Documents
Now that there is a data on our database, let's delete it:
MongoDB Enterprise >
MongoDB Enterprise > db.Person.remove()

2017-02-05T15:36:30.004+0530 E QUERY    [thread1] Error: remove needs a query :
DBCollection.prototype._parseRemove@src/mongo/shell/collection.js:409:1
DBCollection.prototype.remove@src/mongo/shell/collection.js:434:18
@(shell):1:1

MongoDB Enterprise > db.Person.remove({"name":"Rakesh"})

WriteResult({ "nRemoved" : 1 })

--This does not actually remove the collections, and any meta information about it will still exist.

MongoDB Enterprise > show collections;
Person
MongoDB Enterprise >