Meghadoot Mobile Company Background The development and design of a data warehouse is inextricably linked to the business needs of an enterprise.. Meghadoot Mobile Company MMC is a ficti
Trang 1Meghadoot Mobile Company Background
The development and design of a data warehouse is inextricably linked to the business needs of
an enterprise Meghadoot Mobile Company (MMC) is a fictitious company that has a need for an analytical data warehouse
Meghadoot Mobile Company has been in business since 1990 Like every Mobile Service
Provider, the company is searching for new business in an already saturated market
Distribution channels have been traditionally through direct sales and Franchise outlets Recently, MMC started offering products through the Internet
You explore MMC’s business needs more fully as you progress through the design process
Throughout the remaining practices in this course, you refer to MCC’s issues and requirements to help you make critical design decisions
Business Situation
In January 2005 and later due to WTO agreement implementation there will be drastic changes at MMC business Due to increased competition it is expected that Sales will be lower than they have been in the previous years The flagship products may become out-dated and may not do well in market
The vice president of sales and marketing wants to understand what is driving the business He wants to know the reason for sales spikes Sales volumes that may be generated through the Internet, but wants to know whether this channel is introducing new clients to MMC or whether it
is acquiring other channels
The president is concerned because the aggregate margins may shrink and therefore may hit the bottom line and top lines of the company
Technology is changing very fast and may see more and more domestic and foreign competitors
Business Objectives
In strategic discussions, managers articulate the objectives and goals for the company, for the supply side–Inventory Management, Planning and Operations–and for the demand side–sales and marketing MMC has chosen to focus on the demand side for the initial warehouse
implementation
Information Requirements
Through interviews and the requirements-building process, you have identified the following information needs:
Analyze industry trends and target specific market segments
Identify best and worst sellers
Identify sales opportunities through custom package offerings or by capitalizing on buying trends
Trang 2 Identify product trends and develop a channel strategy.
Analyze sales over multiple promotional cycles
Analyze sales channels and increase profits
These provide a guideline to your design both in the data that should be included and the
arrangement of that data to support this analysis
Meghadoot Mobile Company Value Proposition
After much discussion and evaluation, the management of MMC identified its greatest business opportunities that could be addressed through a data warehouse
The proof-of-concept deliverable for MMC wants to analyze Customer Behavior to understand the following issues:
Product Strategy: What products are selling? What products should we offer?
Customer Identification: Who are our customers, what are they buying
Objective
In this practice you learn how to identify source data for your data warehouse While discovering the source databases, you adjust your warehouse to schema to accommodate the limitations and constraints of the data that is available
In this practice, you:
Design the logical model for the data warehouse for MMC
Identify the subject area for MMC data warehouse application
Design a conceptual model
Create the logical model
Next you will design the physical model for the data warehouse for MMC
Identify the attributes for the data warehouse logical model
Map the source data from the OLTP model to the data warehouse model
Identify any data transforms
Review
Creating the logical database design involves:
Choosing primary keys
Mapping entities to tables
Mapping attributes to columns
Mapping relationships to foreign keys
Choosing subtype options (and identifying any inheritance properties)
Choosing optimality
Choosing candidate index columns
Trang 3Note: Although indexes are not strictly part of logical design, in reality they are usually identified
at this stage
Begin your design by identifying the subject areas of your business to be implemented in the first (current) increment Consider only the business view of the information requirements Your perspective needs to be independent of any implementation constraints or concerns at this stage
Subject areas are building blocks that are uniquely identifiable and usable across the business These subjects need to be founded on long-term, stable business concepts
Note: The subject areas become the dimensions of the star model.
The logical design may consider implementation consequences Changes need to be made to the logical model for technical reasons, such as:
Scope of the data warehouse
Business entities and attributes
Business rules, domain, cardinality
Relationships between business entities
Referential integrity rules
MCC Subject Areas
From the MCC business case, the following subject areas have been identified for the conceptual model:
Customer
Time
Place
Age
Gender
Consumption level
Customer type
Customer occupation
Credit level
Business brand
Business category
Although it may be tempting to create the entities for the warehouse from existing systems, you need to define the entities from the subject areas identified by your specific analysis of business requirements These entities become the dimensions of your warehouse model
The next step in creating your conceptual model is to identify the relationship within each entity and between entities The relationships are important in this model, as your starting point
Identifying the Attributes
Now that you have identified the entities and relationships between them from the outlined business requirements you can now determine in your what sort of conceptual model, information about each entity is of interest The attributes are the descriptors in the entity Attributes may also become primary and foreign key values
Trang 4The data warehouse may contain:
Descriptive attributes such as name, Occupation, and Credit Limit
Key attributes such as order and people identifiers
Level indicators
Key values are determined in your next step
Note: The attributes of entities ultimately become the table columns in the logical model
Identifying the Critical Business Measures
The critical measures of the business are the facts by which the business is evaluated Consider
different ways the business might need to be viewed as you define these measures For example consider:
Internal measurements such as salesperson quota, or percentage of default Payments
Customer measures such as discounts extended, or days between order and receipt
Marketing information that may include demographic data, or industry trends
The key performance measures represent the direct results of a business event and not an analysis about what the event means
Note: These measures typically become the attributes of the fact table.
Defining the Keys
Your entity relationship model now contains the:
Relationships between entities
Attributes for each entity
A list of measures
Derived data attributes to hold calculated values
Map Source System to Subject Area
As you consider which system can provide the warehouse with data, conduct a life cycle mapping
of sources to the subject areas For example, looking at the Order Entry System for Global Computing Company, you see that the Customer subject area is created, updated, and read through this system
You should assess each source system for its viability to act as an accurate, continuing source of data by evaluating the source system’s:
Application type, whether package or custom
Architecture, whether open or proprietary
Age
Database size and growth pattern
Maintenance history
Size of user base and criticality of data
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These measures indicate the long term stability of the system as a data provider for the warehouse