Deck 9: Designing Databases

Question 1

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

Answer 1

False

Question 2

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

Answer 2

True

Question 3

In general,data structure refers to grouping attributes from the logical database model into physical records.

Answer 3

True

Question 4

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

Question 5

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

Question 6

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

Question 7

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

Question 8

Each column in a relation corresponds to an entity type.

Question 9

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

Question 10

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

Question 11

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 12

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

Question 13

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

Question 14

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

Question 15

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

Question 16

File and database design occurs in two steps.

Question 17

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

Question 18

A relation corresponds to a computer file.

Question 19

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

Question 20

Conceptual modeling is performed during systems design.

Question 21

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

Question 22

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

Question 23

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

Question 24

An attribute can be functionally dependent on more than attribute.

Question 25

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

Question 26

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

Question 27

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

Question 28

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 29

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

Question 30

Denormalization reduces the chance of errors introduced by normalizing relations.

Question 31

Generally speaking,a physical table corresponds to a relation.

Question 32

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

Question 33

Transitive attributes are attributes that determine other attributes.

Question 34

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

Question 35

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

Question 36

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

Question 37

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

Question 38

Normalization is based on an analysis of weak entities.

Question 39

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 40

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

Question 41

Multiple key retrieval is possible with the hashed file organization.

Question 42

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

Question 43

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 44

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

Question 45

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

Question 46

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

Question 47

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

Question 48

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

Question 49

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

Question 50

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 51

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 52

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 53

Sequential files are practical for random row retrievals.

Question 54

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 55

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 56

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 57

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 58

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 59

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 60

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 61

A particular relationship between two attributes best defines:

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

Question 62

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 63

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 64

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 65

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 66

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 67

A named two-dimensional table of data is a:

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

Question 68

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 69

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 70

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 71

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 72

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 73

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 74

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 75

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 76

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 77

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 78

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 79

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 80

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