Discuss the lack of data independence in file systems

Assignment Help Database Management System

Reference no: EM132874963

Part 1

Answer the following questions.
Review Questions
1. Discuss each type of the following terms
a. Data
b. Field
c. Record
d. File

2. What is data redundancy and which characteristics of the file system can lead to it?

3. Discuss the lack of data independence in file systems.

4. Explain the difference between data and information.

Part 2

MULTIPLE CHOICE QUESTIONS.

1. One of the advantages of a relational database model is ____.
1 structural dependence
b. conceptual complexity
c. easier database design
d. complex database design

2. Using network terminology, a relationship is called a(n) ____.
a. member
b. owner
c. set
d. table

3. Given its parent/child structure, the hierarchical model yields integrity and consistency; there cannot be
____________________.
a. a root
b. a large amount of data
c. a child without a parent
d. many transactions

4 A relational database model ____.
a. does not require substantial hardware and system software overhead
b. does not promote "islands of information" problems
c. allows trained people to use a good system poorly
d. lets the user operate in a human logical environment
5. Because an RDBMS hides the system's complexity from the user/designer, ____.
a. it does not exhibit data independence
b. it does not exhibit structural independence
c. data management is easier
d. data management is very difficult

6.. A data model must represent the ____ world as closely as possible.
a. machine
b. logical
c. real
d. abstract

7. Which of the following is not a degree of abstraction as defined by ANSI/SPARC?
a. Conceptual
b. Physical
c. Internal
d. External

8. The ____ model presents a global view of the database.
a. network
b. physical
c. conceptual
d. logical

9 What type of relationship is expressed with the phrase "Painter paints Painting"?
a. 1:M
b. 1:1
c. M:1
d. M:N

10 Which of the following is least likely to be a business rule as relates to data modeling?
a. A customer may make many payments on an account.
b. A machine operator may not work more than 10 hours in a 24-hour period.
c. A training session cannot be scheduled for fewer than 10 employees or more than 30 employees.
d. Casual Fridays take place in the summer.

REVIEW QUESTIONS

1. Discuss the importance of data modeling.

2. How do you translate business rules into data model components?

3. What three languages were adopted by the DBTG to standardize the basic network data model, and why was such standardization important to users and designers?

4. Use the scenario described by "A customer can make many payments, but each payment is made by only one customer" as the basis for an entity relationship diagram (ERD) representation.

5. What is a relationship, and what three types of relationships exist?

6. Give an example of each of the three types of relationships.

7. What is a table, and what role does it play in the relational model?

8. What is logical independence?

9. What is physical independence?

Part 3

Problem Solutions

1. Use the contents of Figure 2.3 to work on the following problem.

Write the business rule(s) that governs the relationship between AGENT and CUSTOMER.

2. Given the business rule(s) you wrote in Problem 1, create the basic Crow's Foot ERD.

1. Nulls, if used improperly, can create problems because they can represent ____.
a. a default value
b. a known, but missing, attribute value
c. zero
d. an unsortable value

2 The referential integrity rule requires that ____.
a. every null foreign key value must reference an existing primary key value
b. an attribute has a corresponding value
c. every non-null foreign key value reference an existing primary key value
d. you delete a row in one table whose primary key does not have a matching foreign key value in another table

3. According to E.F. Codd, another word for the term "relation" is ____.
a. datafile
b. data index
c. table
d. data query

5. A table can be logically connected to another table by defining a ____.
a. hyperlink
b. common attribute
c. primary key
d. logic key

7. A primary key that consists of more than one field is called a ____ key.
a. composite
b. secondary
c. group
d. foreign

8. A field that consists of integer values is a ____ type field.
a. Date/Time
b. Yes/No
c. Memo
d. Numeric

9. In general terms, the ____ key is an attribute (or combination of attributes) that uniquely identifies any given entity.
a. indexed
b. primary
c. foreign
d. redundant

10. It might take more than a single attribute to define functional dependence; that is, a key may be composed of more than one attribute. A multi-attribute key is known as a ____ key.
a. primary
b. super
c. composite
d. foreign

11. A ____ key is defined as a key that is used strictly for data retrieval purposes.
a. primary
b. foreign
c. secondary
d. data

12. An attribute (or combination of attributes) that uniquely identifies each entity occurence in a
table is called a ____.
a. Superkey
b. candidate key
c. primary key
d. secondary key

13. An attribute (or combination of attributes) in one table whose values must either match
the primary key in another table or be null is called a ____ key.
a. Foreign
b. Candidate
c. Primary
d. secondary

14. A primary key ____.
a. consists of only one field
b. has the same value for all records
c. must contain a unique value for each record within the table
d. is defined automatically

Review Questions

1. What is the difference between a database and atable?

2. Why are entity integrity and referential integrity important in a database?

3. Identify and describe the components of the table shown in Figure Q3.4, using correct terminology. Use your knowledge of naming conventions to identify the table's probable foreignkey(s).

4. Suppose you are using the database composed of the two tables shown in Figure Q3.5.
a. Identify the primarykeys.

b. Identify the foreignkeys.

c. Create theERM.

d. Suppose you wanted quick lookup capability to get a listing of all plays directed by a given director. Which table would be the basis for the INDEX table, and what would be the index key?

e. What would be the conceptual view of the INDEX table that is described in Part d? Depict the contents of the conceptual INDEXtable

Attachment:- Tutorials Week.rar

Reference no: EM132874963

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