Mongo DB - Schema less database - Series 2

Overview:  In this section we'll see how to start the Mongo DB engine, create database and basic CRUD operations

Starting Mongo DB

The two "most important" applications are the mongo and mongod

applications. 

The mongo application allows you to use the database shell; this shell enables you to

accomplish practically anything you'd want to do with MongoDB.

The mongod application starts the service or daemon, as it's also called. There are also many flags you can set when launching the MongoDB applications

executing the mongod.exe from command prompt (Tips: Set the path in the environment variables, so that you don't need to navigate to the actual folders)

There is a nice comparison between Mongo DB and Oracle & My SQL in Mongo web site, a helpful tip for newbies http://www.mongodb.org/display/DOCS/SQL+to+Mongo+Mapping+Chart

I've listed down a key comparison between Mongo and other RDBMS

RDBMS	MONGO
Database	Database
Tables	Collections
Rows	Documents

In MongoDB, a document is an item that contains the actual data, comparable to a row in SQL.

Important Note:

Mongo DB is case-sensitive

$ symbol is reserved for many built-in functions

 

DATATYPES

String	Text values
Integer (32b and 64b)	Numerical values
Boolean	True or False
Double	Floating point values
Min/Max	Comparing values against Lowest  and Highest BSON elements
Arrays	Store array of values
Timestamp	Store Time stamp
Object	Object  type values
Null	Null values
Date*	Current Date
ObjectID*	Documents unique ID
Binary Data*	Binary format data
JavaScript Code*	Store JavaScript code
Regex*	Regular Expression type

*denotes BSON data types

 CRUD Operations

Before i dive in to CRUD operation with example, there are few important commands to do the basic operations like Listing all databases, connecteing to database,  listing all documents, etc...

One interesting command to remember is : 'Show'  this is almost a replacement for 'Select * from'

use	To switch to a db library
show dbs	To view available databases and collections
show collections	To view all available collections for your current database
system.indexes	All the indexed are stored here
db..renameCollection("Target DB")	Renaming a Collection
db..distinct("xxxxx")	Getting distinct data collection