Similarity in a Warehouse and Data Warehouse:
If you are a new born baby or heard about datawarehosuing for first time - here are some definitions of Datawarehouse for you.
We will see the definition given by pioneers later in my post.
a. Datawarehouse is a place where I can store huge amount of data in a systematic manner.
b. Datawarehouse similar Database to is nothing but combination of multiple tables linked to each other through primary key and foreign constraints.
c. Datawarehouse stores data collected over multiple years(Historical).
d. Datawarehouse is used for analyzing the data for decision making purposes of the enterprise.
e. Datawarehouse is a place where we store huge amount of data, from which we can easily extract the data.
Now read this:
Datawarehouse is combination of multiple table linked to each other which stores the historical data in systematic manner which is used for analyzing the data for decision making purposes.
Moving forward - what actually we mean by all these terms.
What do we mean by storing the data in systematic manner and why it is important.
Don't understand anything out of this !!!!
Let's talk about some familiar terms first.
Have you ever got a chance to see any warehouse(not the city retail shop) - The big storage place usually out of city where companies keep there products. And based on the requirements the products are dispatched to retail shops.
Take a look at fig(a) below, a place which is not well arranged and not maintained. Now if I try to go there and get some thing (say - a PENCIL) out of that, it will be really difficult for me.
Fig(a) - A warehouse which is not systematically arranged.
Disadvantages of this place:
1. I am not sure if I have PENCIL.
2. If I am sure PENCIL is there, I am not sure where it will be
3. I am not sure how many PENCIL's I have?
4. Even if I am aware that I have pencil in that huge stock, I am not sure how will i reach there and take that out..
Now have a look at fig(b) below, a nice place !!!
Fig(b) - A warehouse which is systematically arranged.
Advantages of this place (you all can now easily answer..)
1. I am aware of the place where PENCIL is present.
2. I can easily go there and search for the PENCIL.
3. I will save my time, since I know the place where PENCIL is kept.
4. Since place is properly arranged, I will be aware how many PENCIL's we have stored.
Now relate above figure(a) as your data and fig(b) as datawarehouse.
Only having the data is not enough, having the data systematically arranged is important so that you can use that data for analysis and other purposes in future. - This is where Datawarehouse helps.
You all know every company which works in whatever corner of this world generates Data - some generate huge data(Amazon.com, Wallmart etc) and some generate little data(a new start up). So when we see there are so many advantages of having a Datawarehouse why don't every company have a datawarehouse.
Friends - you might have heard - Every coin has 2 sides. So when Datawarehouse brings in so many advantages, it comes to you with some disadvantages.
To list a few:
1. Heavy cost of building the datawarehouse - you need integration tools, you need reporting tool, You need the storage devices etc.
2. Heavy cost of maintaining the datawarehouse.
The cost is the primary aspect which stops many companies from having a datawarehouse.
In the next post we will see the definition of Datawarehousing.