DWH Material - II

ODSThe Operational Data Store (ODS) is a subject oriented, integrated, volatile & current data store containing detailed corporate data. ODS stores only a specific data (Ex. credit data) from different systems. Because it is always current, it requires very frequent data loads from source systems to the ODS.

Hierarchical Relationships

Any dimension's members may be organized based on parent-child relationships, typically where a parent member represents the consolidation of the members which are its children. The result is a hierarchy, and the parent/child relationships are hierarchical relationships. For example, the Time dimension would contain the following hierarchy
Day – Week – Month – Quarter – Year.Based on the business queries, such hierarchies would be formed in all dimensions.

ExtractionRefers to the process of extracting data from OLTP systems by means of scripts/tools for use in the data warehouse.

TransformationRefers to a set of procedures that are used to ensure the uniformity of data in the warehouse. Multiple OLTP systems may store the same data in different formats. For example, gender may be stores as Male/Female, 1/0, M/F. The process of standardizing this storage and applying the standard for all extracted data is called transformation.
CleaningRefers to the process of validating the extracted data. The business queries would specify some business rules that the extracted data has to undergo. The process of applying these rules is called cleansing.

ETLExtraction, Transformation & Loading process loads the data from heterogeneous source systems to the data warehouse. The data is also cleansed by eliminating duplicate rows, standardizing on acronyms (For ex, co., comp., company etc) in the staging area. The ETL process is triggered at a frequency based on the business needs.

Multi-dimensional/HyperCube/CubeA group of data cells arranged by the dimensions of the data. For example, a spreadsheet exemplifies a two-dimensional array with the data cells arranged in rows and columns, each being a dimension. A three-dimensional array can be visualized as a cube with each dimension forming a side of the cube, including any slice parallel with that side. Higher dimensional arrays have no physical metaphor, but they organize the data in the way users think of their enterprise. Typical enterprise dimensions are time, measures, products, geographical regions, sales channels, etc.

Member/AttributeA dimension member is a discrete name or identifier used to identify a data item's position and description within a dimension. For example, January 1989 or 1Qtr93 are typical examples of members of a Time dimension. Wholesale, Retail, etc., are typical examples of members of a Distribution Channel dimension.

Consolidation/AggregationMulti-dimensional databases generally have hierarchies or formula-based relationships of data within each dimension. Consolidation involves computing all of these data relationships for one or more dimensions, for example, adding up all Departments to get Total Division data. While such relationships are normally summations, any type of computational relationship or formula might be defined.

DWH Material

Business Query

This refers to the set of queries that the warehouse would be expected to answer. Business queries define the structure and the usage of the warehouse. This is the reason that warehouse models follow a business model rather than the operational model used in transactional systems. A sample business query would be: ‘List all stores that showed a profit increase of over 10% for the northwest region for the last quarter’.

OLTP

On-line Transaction Processing (OLTP) systems are the operational systems that record and process the day to day transactions. Hence they are always current. OLTP systems do not support adhoc queries because they store data mostly in Entity Relation model. (Ex. NM Spot TV)

Dimensional Model

Dimensional Model is the logical design technique often used for data warehouses. It contains the same information as an Entity Relation model but packages the data in a symmetric format whose design goals are user understandability, query performance and resilience to change.

FactFacts are the numerical measurements of the business. They are continuously valued and additive. The term ‘FACT’ refers to the subject areas that are to be analyzed. Consider an example in which a retail company wishes to employ a data warehouse. The ‘Facts’ for this warehouse would be the subject areas that the managers of the company would like to analyze (ex. Sales, Inventory, Profit etc). Examples for fact are cost price, sold price, units sold.

DimensionDimensions represent those data element that would be used for analyzing the Facts. For example, the above listed facts would be analyzed using the dimensions of Time (to provide time-based analysis), Geography (To provide performance analysis across regions), Product (To provide analysis across products). Dimensions will store the textual descriptions of the business. Examples are product definition attributes like color, size etc.

Few Minutes for Our Country (INDIA)

Hi Friends,

  

The Government has put condition to get 25 crore people to support JanLokPal. To give your support call 02261550789 (as given by Kiran Bedi) from your mobile no. Your Call will disconnect after 1 ring and your no registered automatically. You will get an SMS confirming this. Do it along to all your friends. Forward to as many people as you know .. verbally, by mails, by messages. Support Anti-corruption campaign lead by Anna Hazare ...Jai Hind.

Please FORWARD to save ourselves

Anna Hazare says bring back the Black Money.

Do u know what will happen if 1,456 Lac Crores comes back.

1. India Financially No.1

2. Each district will get 60000 crores & each village will get 100 Crores

3. No need to pay taxes for next 20 yrs.

4. Petrol 25 Rs, Diesel 15 Rs, Milk 8 Rs.

5. No need to pay electricity bill.

6. Indian borders will become more stronger than the China Wall.

7. 1500 Oxford like Universities can be opened.

8. 28,000 kms Rubber road (like in Paris) can be made.

9. 2,000 hospitals (with all facilities) all medicine Free.

10. 95 crore people will have their own house.

Support Anna Hazare by forwarding this message to atleast 10 Indians.

10 things to know about Anna Hazare 'n Jan Lok Pal Bill.. !
1. Who is Anna Hazare?

An ex-army man. Fought 1965 Indo-Pak War

2. What's so special about him?

He built a village Ralegaon Siddhi in Ahamad Nagar district, Maharashtra

3. So what?

This village is a self-sustained model village. Energy is produced in the village itself from solar power, biofuel and wind mills.

In 1975, it used to be a poverty clad village. Now it is one of the richest village in India. It has become a model for self-sustained, eco-friendly & harmonic village.

4. Ok,...?

This guy, Anna Hazare was awarded Padma Bhushan and is a known figure for his social activities.

5. Really, what is he fighting for?

He is supporting a cause, the amendment of a law to curb corruption in India.

6. How that can be possible?

He is advocating for a Bil, The Jan Lokpal Bill (The Citizen Ombudsman Bill), that will form an autonomous authority who will make politicians (ministers), beurocrats (IAS/IPS) accountable for their deeds.

It's an entirely new thing right..?

In 1972, the bill was proposed by then Law minister Mr. Shanti Bhushan. Since then it has been neglected by the politicians and some are trying to change the bill to suit thier theft (corruption).

7. Oh.. He is going on a hunger strike for that whole thing of passing a Bill ! How can that be possible in such a short span of time?

The first thing he is asking for is: the government should come forward and announce that the bill is going to be passed.

Next, they make a joint committee to DRAFT the JAN LOKPAL BILL. 50% goverment participation and 50% public participation. Because you cant trust the government entirely for making such a bill which does not suit them.

8. Fine, What will happen when this bill is passed?

A LokPal will be appointed at the centre. He will have an autonomous charge, say like the Election Commission of India. In each and every state, Lokayukta will be appointed. The job is to bring all alleged party to trial in case of corruptions within 1 year. Within 2 years, the guilty will be punished. Not like, Bofors scam or Bhopal Gas Tragedy case, that has been going for last 25 years without any result.

9. Is he alone? Whoelse is there in the fight with Anna Hazare?
Baba Ramdev, Ex. IPS Kiran Bedi, Social Activist Swami Agnivesh, RTI activist Arvind Kejriwal and many more.

Prominent personalities like Aamir Khan is supporting his cause.

10. Ok, got it. What can I do?
At least we can spread the message. How?

Putting status message, links, video, changing profile pics.

VANDE MATARAM

JAI HIND!!!!