1.DEFINE THE FUNDAMENTAL CONCEPTS OF THE RELATIONAL DATABASE MODEL?
Information is
stored in databases.Databases maintains information about various types
of objects(inventory),events(transactions),people(employees),and
places(warehouses).Information is everywhere of organization.Database models include:
–Hierarchical
database model –
information is organized into a tree-like structure that allows
repeating information (using parent/child
relationships) in such a way that it cannot have too many
relationships.Hierarchical structures were widely used in the first
mainframe database management systems.Hierarchical structure often
cannot be used to relate to structures that exist in the real words.
–Network
database model – a
flexible way of representing objects and their relationships.The network
model allows each record to have multiple parent and child
records,forming a lattice structure.
–Relational
database model –
stores information in the form of logically related two-dimensional tables.
One way to think about data in a relational database is to think about a cube of
data. For example, at The Gap, the CEO, the district managers and the
sales managers might think about their business as selling products
(jeans, sweaters) in many markets (stores, regions) and measuring their
progress over time (days, weeks, months). Many of the questions these
managers have about their business can be answered by looking to the
intersection of data defined by the edges of the cube pictured in Figure
1.
FIGURE 1
2)EVALUATE THE ADVANTAGES OF THE RELATIONAL DATABASE MODEL?
From a business perspective,databases information offers many advantages,including:
INCREASED FLEXIBILITY
-Good
databases can handle a changes quickly and easily,just as any good
business needs to be able to handle changes quickly and
easily.Databases provide flexibility in allowing each user to access the
information in whatever way best suits his or her needs.The distinction
between logical and physical views is important in understanding
flexible databases user views.
–Have only one physical view
Physical
view – deals with the physical
storage of information on a storage device such as a hard disk
–Have multiple logical views
Logical
view – focuses on how users logically
access information to meet their particular business needs.
This separation of logical and physical views is what allows
each user to access database information differently.Database has only
one physical views it can easily support multiple logical views.Foe
example is a mail-order business.One user might want a CRM report
presented in alphabetical format,in which case last name should appear
before first name.Another user,working with catalog mailing system,would
want customer names appearing as first name and then last name.Both are
easily achievable but different logical views of the same physical
information.
INCREASED SCALABILITY AND PERFORMANCE
- A database must scale to
meet increased demand, while
maintaining
acceptable performance levels.Only a databases could "scale"to handle
the massive volumes of information and the large numbers of users
required for the successful launch of the Ellis Island website.
–Scalability – refers to how well a system
can adapt to increased demands
–Performance – measures how quickly a system
performs a certain process or transaction
Some
organization must be able to support hundreds or thousands of online
users including employees,partners,customers and suppliers who all want
to access and share information.
REDUCED INFORMATION REDUNDANCY
-
Redundancy is the duplication of information or storing the same
information in multiples places.Redundant information occurs before
organization frequently capture and store the same information in
multiple locations.The primary problem with redundant information is
that it is often inconsistent,which makes it difficult to determine
which values are the most current or most accurate.Eliminating
information redundancy saves spaces,makes performing information updates
easier and improves information quality.
INCREASED INFORMATION INTEGRITY(QUALITY)
- Information
Integrity is a measure of the quality of information.Within a database
environment integrity constraints are rules that help ensure the quality
of information.
Relational integrity constraint – rule that enforces basic and fundamental information-based
constraints. For example an operational integrity constraint would not allow
someone to create an order for a none existent customer, provide a markup
percentage that was negative ,or order zero pounds of raw material from a
suppliers
.Business-critical integrity constraint –rule
that enforce business rules vital to an organization’s success and
often require more insight and knowledge than relational integrity
constraints. Consider a supplier of fresh produce to large grocery
chains such as Kroger.
INCREASED INFORMATION SECURITY
- Information is an organizational asset and must be protected from unauthorized users or misuse.As systems become increasingly complex and more available over the internet,security becomes an even bigger issue.
•
Databases
offer several security features including:
– Password – provides authentication of the user who is
gaining access to the system.
– Access level – determines who has access to
the different types of information and access controls determine what type of access
they have to information. For example customer services representatives might
need read only access to customer order information so they can answer customer
order inquiries,they might not have or need the authority to change or delete
order information.
3. DEFINE A
DATABASE MANAGEMENT SYSTEM AND ITS
RELATIONSHIP TO A WEBSITE?
A database
management system is used to access information from a database. A database management system(DBMs) is
software through which users and application programs interact with a database.
Database management system is a set of
programs that enables you to store, modify, and extract information from a database also provides users with tools to add, delete,
access, modify, and analyze data stored in one location. The user send
requests to the DBMS and the DBMS performs the actual manipulation of the
information in the database. Many
DBMS also include a graphics component that enables you to output
information in the form of graphs and charts. Database and database
management system are essential to all areas of business, they must be
carefully managed.Consider
for example, a company selling sports cars. A database is created with
information on each of its currently available cars e.g. make, model,
engine details, year, a photograph, etc. A visitor to the website clicks
on Porsche, the visitor enters the price range that they are interested
in and hits 'Go'. The visitor is presented with information on
available Porsche cars in their price range and an invitation to
purchase or request more information from the company. The company has
the ability to add new cars to the database, remove them or modify
existing entries this is achieved via a secure administration area on
the website.
EXPLAIN WHY AN ORGANIZATION WOULD WANT TO INTEGRATE ITS DATABASE?
Data
integration refers to the organization’s inventory of data and
information assets as well as the tools, strategies and philosophies by
which fragmented data assets are aligned to support business goals.The company
want to integrate its database because they will
connect,communicate,dealing and having relation with its customer
everyday. Everyday its customers will open the webpage and search
anything appear on the page. Therefore, if the product still available
or not available the supplier must inform the customers
immediately.Publish the information on the web page to make the
customers realize that the product exist or not in the market. Then,
when the customers got information they will not too disappointed and
not waiting too long. Customers satisfy, the business relationship
between sellers and customers will be effective and launch smoothly.
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