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Flashcards in Module 1 Deck (41):
1

A business keeps track of their employees, shifts and dates worked using only the following file:

After learning that Elizabeth Linbreck ceased employment with the business, her entity was deleted from the file, which now looks like this:

Due to the structure of the file, which of the following will occur as a result of this deletion?

A. An update anomaly

B. An insertion anomaly

C. A deletion anomaly

D. An error message will display

 

 

 

 

 

 

ANSWER: C

This file is the only source of both the employee names and the possible shifts. Elizabeth Linbreck was the only one working on the "First-Second Shift". Therefore, deleting Elizabeth Linbreck from the file also deleted any information regarding "First-Second Shift". This is known as a deletion anomaly

2

Read the scenario below, then follow the subsequent instructions.

A small organization stores its data in a file named "ORGDATA.xyz", and uses a custom program to store and access the data in the file. The file is in a format that was created by the organization. Two years ago, the technical team decided to upgrade the file format by moving all records for the same clients physically close to each other in the file. This upgrade necessitated a change to the custom program in order for it to know how to access the data. Last year, the technical team decided to upgrade the file by allowing 255 characters for each client last name, instead of the original 16 characters. This upgrade again required a change to the custom program. Lastly, the file format has no way for one record to reference another record. For example, if two clients live at the same address, the address must be included twice in the file -- once for each client.

 

Select all statements that correctly describe the above scenario.

A. The customer program used to store and access data in the file is structurally dependent upon the file.

B. The file is subject to data anomalies

C. It is impossible to answer any ad-hoc (spur of the moment) questions using the file and program.

D. The customer program used to store and access the data in the file is data dependent upon the file.

E. The file exhibits data redundancy

Answer: A, B, D, E

The file exhibits data redundancy because records cannot reference other records, and so two logically equal pieces of data must sometimes be duplicated. We know this from the fact that the same address is listed once for each client. The customer program used to store and access data in the file is structurally dependent upon the file. because the scenario indicates that two years ago, a change to the structure required a change to the program. The file is subject to data anomalies because it exhibits data redundancy. Any system that allows for duplicate data is subject to update, insertion, and deletion anomalies. The program is data dependent because the scenario indicates that last year, the datatype of one of the fields changed, and that the program needed to change to continue accessing the file. Though use of a DBMS make ad-hoc questions easier to answer, existing data in a file can still be used to do the same.

3

Select all statements that correctly describe an attribute in the relational model.

A. An attribute is a data characteristic of an entity, such as the datae of an order.

B. The existence and properties of an attribute of an entity might be discovered from the business rules.

C. An attribute is the rough equivalent of a field in a file system.

D. Data is more secure when stored in a basic file system than when it is stored in a DBMS.

E.An example of an attribute may be a customer last name

Answer: A, B, C, E

Attributes are used to describe an entity. The field in a file system is an attribute. A row is an entity. An attribute is a characteristic of an entity. A customer last name could be a field in the customer table. Data is more secure when it is stored in a DBMS, since a DBMS has many fine-tuned privileges and other advanced security mechanisms.

4

  1. Read the following paragraph, then follow the subsequent instructions:

 

At times, photographers employed at this agency may take many publishable photographs in a single day, although taking many publishable photographs may not be possible due to extreme weather or other unforeseen circumstances.

Most photographers employed at this agency are very capable individuals.

 

Select all statements that correctly assert a reason why the paragraph is not suitable to be a business rule.

 

A. Because the paragraph is not precise, it is not suitable to be a business rule.

B. Because the paragraph is ambiguous, it is not suitable to be a business rule.

C. Because the paragraph does not state the intended message concisely, it is not suitable to be a business rule.

D. Because the paragraph is not entertaining and exciting, it is not suitable to be a business rule.

E. Because the paragraph does not define entities clearly, it is not suitable to be a business rule.

ANSWER: A, B,C

Business rules must be correct, brief, precise, and unambiguous; having entertainment value is not considered important for a business rule. Business rules must be brief so that its intended meaning can be converted easily into database and system requirements. The above paragraph does not give precise inference to several ideas introduced, including how "very capable" would be modeled, nor the exact amount of "many publishable pictures”. The above paragraph mentions "many publishable pictures", but does not provide any contrasting information to indicate how many or how much more than usual. There are several entities defined, including Photographer, Agency, and Photograph.

5

Select all statements that correctly describe business rules.

A. Business rules can be derived from an organization's operations.

B. When designing databases, business rules are useful to businesses and government, but not to other types of organizations such as religious groups or research laboratories.

C. Business rules rarely describe details; they almost always describe high level items.

D. Business rules should be documented if they are to be used as a basis for a database design.

Answer: A, D

Business rules are helpful to all types of organizations. Business rules should be documented and reviewed. Business rules are commonly derived from the organizations operations. Business rules oftentimes describe details.

6

Select all statements that correctly describe business rules.

A. Some business rules help standardize an organization's view of data.

B. Some business rules allow the designer to understand the nature, role, and scope of the data.

C. Some business rules act as a communications tool between users and designers.

D. Business rules define all applicable database constraints, no matter how detailed the constraint is.

E. Business rules are by definition valid for all data for all time, so they are well suited for database design.

Answer: A, B, C

Business rules must be easy to understand and widely disseminated, to ensure that every person in the organization shares a common interpretation of the rules. Some business rules are essential to database design because they allow the designer to know the scope of the data to be stored in the database. Business rules describe constraints on the data at a higher level, but particular implementations of constraints in the database are not explicitly defined by the business rules. Business rules help the users describe what is needed, and help designers understand what needs to be done. Business rules help everyone understand the company's view.

7

You are given the following business rules:

  • An actor acts in many movies.
  • Each movie is acted in by many actors.

Select all alternatives below that correctly describe the relationship described by the business rules above.

A. This relationship can be represented by this entity relationship diagram:

B. This relationship can be classified as a one-to-many (1:M) relationship

C. This relationship can be represented by this entity relationship diagram:

D. This relationship can be classified as a many-to-many (M:N) relationship

 

 

Answer: A, D

8

Select all that is true of the conceptual model. (Check all that are true.)

A. Changes in the hardware or software will have no impact on the database design at the conceptual model level.

B. The conceptual model integrates all external views into a single global view of the data in the enterprise.

C. The most widely used conceptual model is the entity relationship model.

D. The conceptual model is independent of software, but dependent on hardware.

Answers: A, B,C

9

Select all that are true of constraints. (Check all that apply.)

A. A constraint can be a restriction that data must satisfy.

B. An example of a constraint when it is applicable to databases could be: A state code must be two characters.

C. A business rule is always a constraint.

D. The business rule, “We try to increase our prices when our main competitor increases their prices” would be appropriate to implement as a database constraint.

E. A constraint is important to help ensure data integrity.

Answers: A, B, E

10

Select all statements that are advantages of use a database management system (DBMS) over use of a basic file system.

A. Database systems can be designed to minimize the risks of data inconsistencies.

B. It is easier to change to a database system made by a different vendor than to change to a hard drive made by a different vendor.

C. Databases are easier to design and manage than spreadsheets.

D. Database systems improve the access to data, so there are fewer data anomalies and less redundancy.

Answer: A, D

Database systems improve the access to data, and can be designed to minimize the risks of data inconsistencies. Databases require skilled personnel to run them. Costs are high, and there is typically more data in a database to manage than a spreadsheet. It is more difficult to change database vendors than durable storage vendors. One reason is that both file systems and hard drive interfaces are highly standardized and are designed to be interoperable, while each DBMS has its own set of supported SQL, metadata, and tools.

11

Select all that is true of DBMS functions. (Check all that apply.)

A. Security management, backup and recovery management, and multiuser access control are important functions of commercial DBMS.

B. Common commercial DBMS provide data access through a query language.

C. One of the DBMS functions is control concurrent transactions.

D. Users are aware of all DBMS functions.

Answer: A, B, C

12

Select all statements that are disadvantages of using a database management system (DBMS) over use of a basic file system.

A. Database systems require complex DBMS software and skilled personnel, so costs can be higher than for spreadsheets or flat files.

B. DBMS vendors often upgrade their products, so there are additional costs to keep the database softwareup to date.

C. When only a small amount of data is stored, using a database for the data results in very poor performance when compared to using a file system for the data.

D. Typically more skilled personnel are needed to maintain database systems than to maintain basic file system storage.

A, B, D

Costs are higher with database systems due to the complexities and high salaries of the database staff. Vendors always update their products. This is nothing new, as with a tech product there are always new releases. DBMS are more complex than basic file systems, and thus necessitate more skilled personnel. For example, a DBMS may need its own dedicated database administrator, a database developer, and a data modeler. Databases are quite capable of handling small amounts of data, and still provide bettersecurity, performance, and ease of access when compared to file systems.

13

Select all statements that correctly describe a database management system (DBMS) function.

A. The DBMS makes it possible to query and update data.

B. Since the DBMS will allow more users to make updates, there will be more data inconsistencies.

C. The DBMS helps create an environment in which end users have better access to more and bettermanaged data.

D. The DBMS allows concurrent access to data.

E. The DBMS will make the data more available to users, so there will be more security breaches.

Answer: A, C ,D

14

Select all statements that correctly describe a database.

A. It is generally accepted that there are only three kinds of databases.

B.  A database organizes data in a logical way.

C. A database management system helps manage the database and its data.

D. A database stores data about data to assist in data management.

Answer: B, C, D

Databases do indeed store metadata -- data about data -- to assist in the database's management of the data. For example, when a table is created in a relational database, the database must store the names, number, and datatypes of the table's columns. Unless data is stored in a logical way, it is not particularly useful. The database management system assists in managing the database itself, and helps controls access to the database. If the database is the library, the database management system is the librarian. There are many kinds of databases, which depend upon the number users supported, the kinds of use, and location. The database management system is generally the only mechanism through which the database's data may be updated.

15

Select all statements that correctly describe a difference between a DBMS and a basic file system.

A.  A properly designed file system exhibits structural independence, while a properly designed DBMS exhibits structural dependence.

B. A DBMS provides several important functions that guarantee the integrity and consistency of the data in the database, while file systems generally do not.

C. Extensive programming must be performed to retrieve, manipulate and store data in a DBMS, while a filesystem usually provides a language whereby data can be accessed, modified, and stored fairly easily.

D. Structural changes are difficult in a file system, and less difficult in a DBMS.

Answer: B, D

A properly designed file system exhibits structural dependence, while a properly designed DBMS exhibits structural independence. A DBMS has several functions to guarantee the integrity and consistency of the data in a database, including associating data types with data, providing nullability constraints, and providing security constraints. The DBMS usually provides a simpler query language, while extensive programming must be performed to do the same on a file system. Structural changes to a file require rewriting applications code; this is not often required with DBMS.

16

Select all statements that correctly describe a difference between a spreadsheet, such as Microsoft Excel, and a database, such as Oracle.

A. Spreadsheets typically hold more data than databases.

B. A spreadsheet can enforce some data type constraints, but doesn't easily support discreet integrity constraintslike foreign keys.

C. A spreadsheet doesn t have native capabilities to manipulate data using a standard.

D. A spreadsheet does not support database functionalities like transactions, concurrency control or data integrity.

E. A database allows users to manipulate the data using a standard query language, but a spreadsheet does not.

Answers: B, C, D, E

A spreadsheet does not support many database functions such as concurrency, integrity enforcement, and transactions. Spreadsheets can enforce some constraints, but they are weak and do not do nearly as much as database constraints. A spreadsheet can have relationships, but they are harder to create and manage than a database. Spreadsheets do not have native capabilities to manipulate data using a standard like databases. Databases are usually much larger than spreadsheets. There are limitations in spreadsheets of how much data they can hold.

17

Select all statements that correctly describe a main component of a database environment.

A. Operating systems are a main component of database systems.

B. Textbooks are a main component of database systems.

C. Database administrators are a main component of database systems.

D. Storage devices are a main component of database systems.

E. End-users are a main component of database systems.

Answers: A, C, D, E

The five main components of a database system are: Hardware, Software, People, Procedures, and Data. A storage device is a type of hardware. An end-user is a type of person. A database administrator is a type of person. A textbook is not a type of hardware, software, person, procedure, or data. An operating system is an example of software.

18

Select all that are true of having a DBMS supporting software applications?

A. The DBMS makes it possible to query or update data.

b. The DBMS allows concurrent user access to the same data.

c. Since the DBMS will allow more users to make updates, there will be more data inconsistencies.

d. The DBMS will make the data more available to users, so there will be more security breaches.

e.The DBMS helps create an environment in which end users have better access to more and bettermanaged data

Answers: A,B, E

19

Select all statements that correctly describe data modeling, one of the most important steps in database design.

A.  Most users have a difficult time understanding entity-relationship diagrams or similar data models.

B. In a database environment, a data model represents data, the relationships between data, data constraints, and other aspects of data.

C. A data model is usually represented in a graphical form such as an entity-relationship diagram because the graphics facilitate communication between the people who understand the requirements and the people who are designing the database.

D. Data Modeling is an early step in designing a database.

Answers: B, C, D

Data modeling is one of the first steps in designing a database. A data model is represented in graphical form so that the database designers can understand the requirements. It is a simple representation of aspects. A data model represents a simple diagram of complex data structures. Most users have an easy time understanding entity-relationship diagrams because the conceptual model is a simple representation.

20

Select all statements that correctly describe database design.

A. The expected use of the database should be decided as part of the initial database design.

B. The expected size that the database will be in ten years should be decided as part of initial database design.

C. The same design approach is usually applied to both data warehouses and transactional databases.

D. A badly designed database can perform poorly.

Answers: A, D

A good database design should scale well, so size is not a significant consideration. The central issue must always be the database's expected use, also known as the functionality that it is to support. A badly designed database will perform poorly. A data warehouse and a transactional database will have different design approached because they have different intentions. Data warehouse is historical and aggregated data.

21

Select all that are true of a database schema.

A database schema groups the objects by owner.

b. A database schema can contain indexes and tables.

c. A database schema can have at most one database object.

d. A database schema can contain a database table.

e. A database schema can contain an index.

f. A commercial database instance such as Oracle or Microsoft SQL Server can hold at most one

schema.

Answers: A, B, D, E

22

Select all statements that correctly describe a type of database.

A. A multiuser database supports multiple users at the same time.

B. A distributed database always supports an entire organization and is used by at least 50 people.

C. An operation database is designed to support a company's day-to-day operations.

D. A "single-user database" is also called a "desktop database".

E. A centralized database supports data distributed across several different sites.

Answers: A, C, D

An enterprise database always supports an entire organization and is used by at least 50 people. A desktop database is a specific type of single-user database. Both have in common that the database only supports one user at a time. Only a desktop database, however, requires that the database run on a personal computer. A centralized database only supports data located at a single site, while a distributeddatabase supports data located across several sites. Online transaction processing databases ( also termed OLTP or operational databases) support routine business operations.

23

Which of the following are main components of a database system environment? (Check all that apply.)

a. Database administrators

b. Operating system

c. Users

d. Storage devices

Response

Feedback:

Answers: A, B, C, D

The five main components of a database system are: Hardware, Software, People, Procedures,and Data.

24

The five main components of a database system are: Hardware, Software, People, Procedures,and Data.

  1. Hardware
  2. Software
  3. People
  4. Procedures
  5. Data.

25

This spreadsheet file is kept by a business to record employee names, shift, and dates worked. The spreadsheet exhibits which of the following (check all which apply)?

a. Data Redundancy

b. Data Anomalies

c. Data Dictionary

d. Structural Dependence

 

Answers: A, D

26

View the entity relationship diagram in Crow's Foot notation below Select all statements that correctly describe the diagram.

A. Customer is an entity.

B. Invoice is a relationship.

C. "Has" is a relationship.

D. Customer is a class.

Answers: A, C

The rectangle with the Customer text is an entity. Invoice is an entity. The line with the "has" verb is a relationship. Customer is an entity, which is defined in the entity-relationship model, but it is not a class,which is only correct in the object-oriented model.

27

Which are true about the diagram below?

a. Extended relational data model

b. Entity relationship model

c. Chen Notation

d. Crow's Foot Notation

e. Network model

f. Hierarchical model

Answers: B, D

28

Select all alternatives that represent true statements about this diagram.

a. This diagram is an extended relational data diagram.

b. This diagram is an entity relationship diagram.

c. This diagram is a UML class diagram.

d. This diagram shows relationships.

e. This diagram shows entity attributes.

 

Answers: B, C, D

29

You are given the following entity relationship diagram which is represented as a modified UML class diagram:

Select all of the alternatives below that correctly describe this diagram.

A. The relationship indicated in the diagram is described with the following business rules:

  • Each picture hangs on one wall.
  • Each wall may have one pictures.

B. The relationship indicated in the diagram is described with the following business rules:

  • Each picture hangs on one wall.
  • Each wall may have many pictures.

C. The relationship classification for the relationship describe in the diagram is many-to-many (M:N).

d. The relationship classification for the relationship describe in the diagram is one-to-many (1:M).

e. The relationship classification for the relationship describe in the diagram is one-to-one (1:1).

 

Answers: B,D

30

You are given the following extended entity relationship diagram in UML notation:

a. Entity2 can only have one instance related to each instance of Entity1

b. Entity1 can only have one instance related to each instance of Entity2

c. Entity1 can have many instances related to each instance of Entity2

d. Entity2 can have many instances related to each instance of Entity1

Answers: C, D

31

Which is true about the entity-relationship model?

a. It is semantically richer than the relational model

b. Peter Chen introduced the Crow’s foot Notation

c. It is a widely accepted standard for data modeling

d. There are only two notations: Crow’s foot notation and Chen notation

Answers: A, C

Though the object-oriented model more closely represents the real world than does the relational model, the relational model and its object-oriented enhancement, the ERDM, remains the most widely used from a database design perspective.

32

Select all correct assertions regarding the diagram below.

a. The diagram represents an entity relationship model represented by a UML class diagram.

b.A business rule which could be correctly inferred from the diagram is, "A product is available in many locations."

c. The diagram illustrates a one-to-many relationship.

d. The diagram illustrates a one-to-one relationship.

e.A business rule which could be correctly inferred from the diagram is, "A customer can buy many products."

f. The diagram represents an entity relationship model utilizing Crow's Foot notation.

Answers: A, C, E

33

Select all statements that correctly describe computerized file systems.

A Computerized file systems have data, field, record, and file components.

B. For modern, popular computerized file systems, there are hundreds or thousands of applications that save files in their own unique format.

C. It is more difficult to obtain quick answers from data in a computerized file system when compared to database in a database.

D. A spreadsheet can often be successfully used as a substitute for a database.

 

Answers: A, B, C

Computerized file systems have data, field, record, and file components. One of the common misuses of spreadsheets is to replace databases. For modern, popular computerized file systems, there are hundreds or thousands of applications that save files in their own unique format. For example, Microsoft Word saves its data in one format, Excel in another format, and web browsers in yet another format. One disadvantage of the file system over a database is the virtually infinite variation of the structure of the files. Because of the variation of file structure, it is difficult to obtain quick answers, or even the same amount of answers, from a computerized file system when compared to a database.

34

What type of relationships are expressed by the following phrase?

Each administrative assistant shreds many papers.A paper is shredded by one administrative assistant.

a. M:N

b. 1:1

c. 5:20

d. 1:M

e. Impossible to determine

Answers: D

35

Which of the following correctly describe a relationship in a relational model?

a. A relationship is the equivalent of a field in a file system.

b. A relationship is an association among entities.

c. A relationship is normally expressed in the form of rules.

d. A relationship is anything about which data are to be collected and stored.

e.A relationship is bidirectional. If the customer has a relationship to an invoice, the invoice has a relationship to customer.

Answers: B, E

36

Select all that are true of a query language:

a. is a tool for creating graphical representations of database tables

b. allows the user to specify what must be done without specifying how it should be done

c. is a procedural language

d. is a tool for designing a database

e. is implemented by most DBMS vendors as the Structured Query Language (SQL)

Answers: B, E

37

Select all statements that can be answered with a SQL query.

a. How many customers have joined since January?

b. Which users are allowed to update data?

c. A customer can generate many invoices.

d. An employee will be allowed to copy data.

e. What products are currently priced over $100?

Answers: A, B, E

Most SQL queries are used to answer questions and cover most actions.

38

Select all of the following that are true of SQL commands.

a.The SQL command that lets you select attributes from rows in one or more tables is SELECT.

b. The SQL command that lets you insert rows into a table is UPDATE.

c. The SQL command that lets you permanently save data changes is COMMIT.

d. The SQL command that lets you modify the value of data in a table is MODIFY.

Answers: A,C

39

Select all statements that correctly describe the SQL query below.

SELECT P_DESCRIPT, P_INDATE, P_PRICE, V_CODE FROM PRODUCT                                                      WHERE V_CODE = 21344 OR V_CODE <= 24288;

a. The SQL query returns all records where V_CODE is equal to 21344.

b. The SQL query returns all records where V_CODE is less than 24288.

c. The SQL query returns four rows in the table PRODUCT.

d. The SQL query returns all records where V_CODE is equal to 24288.

Answers: A, B, D

40

5 Main Components of a database system environment?

  1. Hardware
  2. Software
  3. People
  4. Procedures
  5. Data

41