1 Week Homework
Chapter 1, page 29, Review Question 3
Contrast the following terms:
a.
data dependence; data independence
With data dependence, the data used is tied to and part of the application programs that use
the data, where data independence is the separation of data descriptions from the application
programs that use the data. The main difference in practical use is that with data
independence the data can change and evolve without having to change the application
programs that process the data. This flexibility is not available with data dependence.
(Textbook p. 21, Glossary of terms)
b.
data warehouse; data mining
A data warehouse is an integrated decision support database whose content is derived from
various operational databases. Data mining is a means of conduction knowledge discovery
using sophisticated techniques. In a nutshell a data warehouse is a database of databases,
and data mining is a means of extracting data using sophisticated means from that data
warehouse.
(Textbook p. 18, 28, Glossary of terms)
c.
data; information
Data can be defined as facts, text graphics, images, sound, and video segments that have
meaning in the users environment. Information is data (as defined above) that have been
processed in such a way that is useful to the user. Data is the raw state, where information is
the more usable processed version of that data.
(Textbook p. 5)
d.
repository; database
A repository is a centralized knowledge base of all data definitions, data relationships, screen
and report formats, and other system components, where a database is an organized
collection of logically related data. The main difference is that a repository contains an
extended set of metadata which describes the data in the database and is instrumental in
managing the database as well as other components of an information system.
(Textbook p. 4, 24)
e.
entity; enterprise data model
An entity is a person, place, object, event, or concept in the user environment about which the
organization wishes to maintain data. The entity is important to the business. A data model is a
graphical model (diagram) that shows the entities and the relationships among those entities
for the organization.
(Textbook p.10, Glossary of terms)
f.
data warehouse; ERP system
A data warehouse, as defined above, is an integrated decision support database whose
content is derived from various operational databases. An ERP system is a business
management system integrates that all functions of the enterprise, such as manufacturing,
sales, finance, marketing, inventory, accounting, and human resources. ERP systems are
software applications that provide the data necessary for the enterprise to examine and
manage its activities, and data warehouses are the databases ERP systems act upon. If data
warehouses are the mine then ERP systems are the mining equipment.
(Textbook p. 18, 28)
Chapter 1, page 30, Problems and Exercises 1
1. Indicate whether there is a one-to-many or a many-to-many relationship, then diagram with
shorthand notation. (From the text: places, contains, and has are one-to-many)
a.
STUDENT and COURSE
Many-to-many
Register for
STUDENTS
b.
Have
COPIES
Have
Have
SECTIONS
SECTION and ROOM
One-to-many
SECTIONS
e.
Are made from
COURSE and SECTION
One-to-many
COURSES
d.
COURSES
BOOK and BOOK COPY
One-to-many
BOOKS
c.
Are registered by
Are taught in
Contain
ROOMS
INSTRUCTOR and ROOM
One-to-many
INSTRUCTORS
Have
Contain
ROOMS
Chapter 2, page 64, Review Questions 2 and 13
2. Match the terms and definitions
_D_ conceptual schema
_F_ business function
_U_ prototyping
_H_ systems development lifecycle
_A_ functional decomposition
_E_ top-down planning
_B_ incremental commitment
_G_ physical schema
13. Explain the difference between user views, a conceptual schema, and a physical schema as
different views of the same database.
User views are logical descriptions of some portion of the database that is required by a user to perform
some task. A conceptual schema is a detailed, technology independent specification of the overall structure
of a database. A physical schema is made up of specifications for how data from a conceptual schema are
stored in a computer's secondary memory. Comparing these three views dealing with the same database
we could conclude that the user view of the database would have descriptions that would enable a user to
complete a task. The conceptual schema would define how the database is structured or laid out and would
not contain the actual data, but would be more of a blueprint for the layout of the data. The physical schema
would have the nitty-gritty of how the data is actually stored. Its the details about how the user view data is
actually stored in the model defined by the conceptual schema. You could say the physical schema is the
realization (or implementation?) of the conceptual schema.
(Textbook p. 49-51, Glossary of terms)