Deck 9: Designing Databases

Question 1

The network database model is a popular database technology for new information systems.

Answer 1

False

Question 2

Each column in a relation corresponds to an entity type.

Answer 2

False

Question 3

Object-oriented database models are the most frequently used database technologies for new information systems development.

Answer 3

False

Question 4

The selection of the appropriate storage format for each attribute from the logical database model is made during physical database design.

Question 5

One property of a relation is that entries in a given column are from the same set of values.

Question 6

File and database design occurs in two steps.

Question 7

A relation corresponds to a computer file.

Question 8

One of the purposes of database design is to choose data storage technologies that will efficiently,accurately,and securely process database activities.

Question 9

A well-structured relation contains data about two or more entities.

Question 10

The network model is the most common style for a logical database model.

Question 11

During logical modeling,the normalized data requirements from all user interfaces are combined into one consolidated logical database model.

Question 12

Conceptual modeling is performed during systems design.

Question 13

A file organization is an arrangement of related records in secondary memory so that individual and groups of records can be stored,retrieved,and updated rapidly.

Question 14

Each row of a relation corresponds to a record that contains data values for an entity.

Question 15

When using the relational notation,the primary key attribute is indicated by a dashed underline.

Question 16

Generally speaking,logical and physical database design is performed in parallel with other systems design steps.

Question 17

The primary deliverable from logical database design is a conceptual model.

Question 18

Referencing a relation,the sequence of columns cannot be interchanged without changing the meaning or use of the relation.

Question 19

Normalization helps build a data model that is simple,not redundant,and requires minimum maintenance.

Question 20

The selection of data storage technologies is made during the systems implementation and operation phase.

Question 21

The result of normalization is that every nonprimary key attribute depends upon the whole primary key and nothing but the primary key.

Question 22

A data marker is a field of data that can be used to locate a related field or row of data.

Question 23

Efficient use of secondary storage and data processing speed are two goals of physical table design.

Question 24

If for every valid value of A the value of B is determined by the value of A,then B is functionally dependent on A.

Question 25

A derived field is a field that can be derived from other database fields.

Question 26

Generally speaking,a physical table corresponds to a relation.

Question 27

A relation is said to be in second normal form when there are no transitive dependencies.

Question 28

Normalization is based on an analysis of weak entities.

Question 29

A relation is said to be in second normal form when its nonprimary key attributes do not depend on each other.

Question 30

A relation is said to be in second normal form if the primary key consists of only one attribute.

Question 31

Transitive attributes are attributes that determine other attributes.

Question 32

A relation is in second normal form if every nonprimary key attribute is functionally dependent on the whole primary key.

Question 33

Sequential files are practical for random row retrievals.

Question 34

An attribute can be functionally dependent on more than attribute.

Question 35

Denormalization reduces the chance of errors introduced by normalizing relations.

Question 36

Denormalization is the process of splitting or combining normalized relations into physical tables based on affinity of use of rows and fields.

Question 37

A physical file is a named set of table rows stored in a contiguous section of secondary memory.

Question 38

A transitive dependency is an integrity constraint specifying that the value of an attribute in one relation depends on the value of the same attribute in another relation.

Question 39

A default value is a value a field will assume unless an explicit value is entered for that field.

Question 40

A null value is used to represent the zero digit in a relation.

Question 41

File restoration can be achieved through backup copies of a file,audit trails,and row image files.

Question 42

During physical design,you consider:

A)the definitions of each attribute
B)the descriptions of where and when data are entered,retrieved,deleted,and updated
C)the expectations for response time and data integrity
D)all of the above

Question 43

Which of the following is not a key step in logical database modeling and design?

A)Combine normalized data requirements from all user interfaces into one consolidated logical database model.
B)Compare the consolidated logical database design with the translated E-R model and produce,through view integration,one final logical database design for the application.
C)Model how data flow through an information system,the relationships among the data flows,and how data come to be stored at specific locations.
D)Translate the conceptual E-R data model for the application into normalized data requirements.

Question 44

Multiple key retrieval is possible with the hashed file organization.

Question 45

The following are steps to transforming an E-R diagram into normalized relations and then merging all the relations into one final,consolidated set of relations except for:

A)represent entities
B)represent relationships
C)normalize the relations
D)denormalize the relations

Question 46

During logical database design,the work of all systems development team members is coordinated and shared through:

A)the project dictionary
B)scheduled weekly meetings
C)the project leader
D)JAD sessions

Question 47

Indexes should be used judiciously for databases that support transaction processing and other applications with heavy updating requirements.

Question 48

Random key retrieval on the primary key is comparatively slow with the hashed file organization.

Question 49

Using relational notation,an attribute of a relation that is the primary key of another relation is indicated by:

A)an underline
B)a circle
C)a dashed underline
D)italics

Question 50

Which of the following is not associated with database design?

A)Structure the data in stable structures that are not likely to change over time and that have minimal redundancy.
B)The preparation of a final conceptual model and the implementation of the database.
C)Develop a logical database design from which we can do physical database design.
D)Develop a logical database design that reflects the actual data requirements that exist in the forms and reports of an information system.

Question 51

The primary deliverable from logical database design is:

A)normalized relations
B)design specifications
C)an updated baseline project plan
D)a list of alternative design strategies

Question 52

Data security can be built into a file through encryption,passwords,or prohibiting users from directly manipulating a file.

Question 53

Sequential retrieval on the primary key is very fast with the hashed file organization.

Question 54

Designing the database for an Internet-based electronic commerce application differs significantly from the process followed when designing the database for other types of applications.

Question 55

The most common style for a logical database model is the:

A)relational database model
B)hierarchical database model
C)network database model
D)object-oriented database model

Question 56

A named two-dimensional table of data is a:

A)network
B)tree structure
C)relation
D)tuple

Question 57

Indexes should be used generously for databases intended primarily to support data retrievals.

Question 58

When using the sequential file organization,the addition of rows requires rewriting the file.

Question 59

Combining all normalized user views into one consolidated logical database model refers to:

A)requirements structuring
B)view integration
C)normalization
D)file integration

Question 60

A data model that represents data in the form of tables or relations is called a:

A)hierarchical database model
B)network database model
C)relational database model
D)hybrid database model

Question 61

The relation state specifying that nonprimary key attributes do not depend on other nonprimary key attributes is:

A)first normal form
B)second normal form
C)Boyce-Codd normal form
D)third normal form

Question 62

Which of the following statements is true regarding normalization?

A)Normalization is a top-down process.
B)Normalization produces a set of well-structured relations that contain all of the data mentioned in system inputs and outputs.
C)Through the use of anomalies,stable structures are produced.
D)Normalization is an integrity constraint specifying that the value of an attribute in one relation depends on the value of the same attribute in another relation.

Question 63

A binary one-to-many relationship in an E-R diagram is best represented by:

A)the creation of a separate relation;the primary key of this new relation is a composite key consisting of the primary key for each of the two entities in the relationship
B)adding the primary key attribute (or attributes)of the entity on the one side of the relationship as a foreign key in the relation that is on the many side of the relationship
C)adding the primary key attribute (or attributes)of the entity on the many side of the relationship as a foreign key in the relation that is on the one side of the relationship
D)creating a relation with a composite primary key and nonkey attributes

Question 64

Which of the following properties of a relation states that an entry at the intersection of each row and column is single-valued?

A)Entries in cells are simple.
B)Entries in columns are from the same set of values.
C)Each row is unique.
D)The sequence of rows is insignificant.

Question 65

If order number serves as the primary key in the ORDER relation and also appears as a nonprimary key attribute in the INVOICE relation,then order number is said to be a:

A)foreign key
B)candidate key
C)pointer
D)relationship key

Question 66

Each regular entity type in an E-R diagram is transformed into a:

A)row in a relation
B)column in a relation
C)relation
D)tuple in a relation

Question 67

Assume the structure of a relation is EMPLOYEE (Emp_ID,Name,Dept,Salary).The number of attributes for this relation would be:

A)three
B)four
C)five
D)six

Question 68

For a unary one-to-one relationship between two entities A and B,the relationship is represented by:

A)adding the primary key of A as a foreign key of B
B)adding the primary key of B as a foreign key of A
C)combining the two entities into one relation
D)either A or B

Question 69

The process of converting complex data structures into simple,stable data structures is referred to as:

A)normalization
B)simplification
C)structuring
D)process modeling

Question 70

For any relation R,if,for every valid instance of A,that value of A uniquely determines the value of B:

A)then a primary dependency exists in the relation
B)then A is said to be functionally dependent on B
C)then B is said to be functionally dependent on A
D)then A and B are candidate keys for the relation

Question 71

Which of the following properties should be satisfied when the identifier of the entity type becomes the primary key of the corresponding relation?

A)The value of the key must uniquely identify every row in the relation.
B)The key should serve as a foreign key in at least two other relations.
C)The key must be a composite of a primary key and a secondary key.
D)The key should be an intelligent key.

Question 72

When transforming an E-R diagram into normalized relations,the identifier of the entity type becomes:

A)the primary key of the corresponding relation
B)the foreign key in the corresponding relation
C)a nonkey attribute in the corresponding relation
D)a secondary key in the corresponding relation

Question 73

A functional dependency between two (or more)nonprimary key attributes in a relation defines a:

A)weak dependency
B)partial dependency
C)simple dependency
D)transitive dependency

Question 74

An entity whose primary key depends on the primary key of another entity is called a:

A)referential entity
B)candidate entity
C)transitive entity
D)weak entity

Question 75

Which of the following is not a true statement regarding a relation?

A)Each relation consists of a set of named columns and an arbitrary number of unnamed rows.
B)Each column in a relation corresponds to an attribute of that relation.
C)An entry at the intersection of each row and column has a single value.
D)Each row in a relation corresponds to an attribute of that relation.

Question 76

To convert a relation to second normal form,you decompose the relation into new relations using the attributes,called:

A)determinants
B)foreign key
C)pointer
D)relationship key

Question 77

For a binary one-to-one relationship between two entities A and B,the relationship is represented by:

A)adding the primary key of A as a foreign key of B
B)adding the primary key of B as a foreign key of A
C)combining the two entities into one relation
D)either A or B

Question 78

When each nonprimary key attribute is identified by the whole key,the relation is said to be in at least:

A)second normal form
B)third normal form
C)fourth normal form
D)fifth normal form

Question 79

A relation that contains a minimum amount of redundancy and allows users to insert,modify,and delete rows without errors or inconsistencies is a(n):

A)independent relation
B)simple relation
C)unnormalized relation
D)well-structured relation

Question 80

A particular relationship between two attributes best defines:

A)context
B)functional dependency
C)normal form
D)structure