ISBC CE 5
In an organization, a single clerk is working in the administrative department. The notation that accurately indicates this relationship is ________. A) 1:N B) N:N C) 1:1 D) N:M
1:1
In a university, each adviser can advise multiple students, but each student can have only one adviser. In a data model, this can be best represented by a(n) ________. A) N:M relationship B) N:N relationship C) 1:N relationship D) 1:1 relationship
1:N relationship
A(n) ________ notation signifies that an adviser can be related to many students and that a student can be related to many advisers. A) 1:N B) N:M C) N:1 D) N:N
N:M
________ describe the characteristics of entities. A) Attributes B) Dependencies C) Cardinalities D) Alternatives
attributes
The general goal of normalization is to ________. A) create a copy of an existing table B) construct tables such that all tables have a similar topic C) convert two or more tables into a single table D) construct tables such that every table has a single topic
construct tables such that every table has a single topic
The little lines in an E-R diagram used as shorthand to represent multiple relationships are referred to as a(n) ________. A) crow's foot B) identifier C) attribute D) entity
crow's foot
Normalized tables eliminate ________. A) data dependency B) data duplication C) data entry D) data conversion
data duplication
Once the users have validated and approved the data model, it is transformed into a ________. A) database design B) requirement report C) knowledge management system D) data repository
database design
The data integrity problem can occur only if data are ________. A) duplicated B) missing C) replaced D) insufficient
duplicated
The easiest time to change the database structure is ________. A) during the data modeling stage B) after constructing the database C) during the database designing stage D) after creating database reports
during the data modeling stage
Maximum cardinality in an E-R diagram refers to the maximum number of ________. A) relationships possible in a diagram B) entities that can be involved in a relationship C) identifiers possible in a particular diagram D) attributes an entity can have
entities that can be involved in a relationship
Which of the following is true of entities? A) An identifier's value is associated with every entity in the data model. B) Entities can only represent a logical construct or transaction, not a physical object. C) Entities' characteristics are described by attributes. D) The relationships between entities are known as attributes.
entities' characteristics are described by attributes
Which of the following is a highly popular technique for creating a data model with which the developers describe the content of a database by defining what is to be stored in the database and the associations among them? A) entity-relationship (E-R) data model B) Unified Modeling Language (UML) C) object-relational model D) data integrity model
entity-relationship (E-R) data model
1:N means that more than one entity is allowed on each side of the relationship.
false
An identifier is an attribute whose value is associated with every entity in the data model
false
Entities have relationships to attributes but not to each other.
false
The crow's-foot notation shows the minimum number of entities that can be involved in a relationship.
false
The data integrity problem can occur only if data are missing.
false
The easiest time to change the database structure is after the database has been constructed and loaded with data.
false
The notation N:N is used to indicate a many-to-many relationship in an E-R diagram.
false
To represent an N:M relationship between two entities, two normalized tables are sufficient.
false
a data model does not depict the relationship among the data
false
________ are attributes whose values are associated with one and only one entity instance. A) Cardinalities B) Descriptors C) Dependencies D) Identifiers
identifiers
Which of the following is true of an E-R diagram? A) Every entity has an identifier. B) Many-to-many relationships are generally denoted as N:N. C) A crow's-foot is required to represent a 1:1 relationship. D) Identifiers are shown in a section at the top of the entity.
identifiers are shown in a section at the top of the entity
Which of the following is true of a data model? A) It is created after the database is designed. B) It is an attribute whose value is associated with only one entity instance. C) It is a logical representation of the structure of data. D) It does not describe the relationships among data.
it is created after the database is designed
Database practitioners classify tables into various ________ according to the kinds of problems they have. A) entities B) cardinalities C) normal forms D) attributes
normal forms
The process of converting poorly structured tables into two or more well-structured tables is referred to as ________. A) replication B) integration C) actualization D) normalization
normalization
A data model is a logical representation of the structure of the data.
true
A vertical bar on a line representing a relationship indicates that there is a minimum requirement for the entity.
true
Database practitioners classify tables into various normal forms according to the kinds of problems they have.
true
Entities have attributes that describe characteristics of the entity.
true
In an entity-relationship (E-R) diagram, a line is used to represent a relationship between two entities.
true
Normalization is the process of converting a poorly structured table into two or more well-structured tables.
true
Tables that are not normalized can have data integrity problems.
true
The N:N notation indicates that the same number of entities are present on each end of the relationship.
true
The general goal of normalization is to construct tables such that every table has a single topic or theme.
true
The maximum number of entities that can be involved in a relationship is known as maximum cardinality.
true
a data model should be transformed into a database design only after the users have approved and validated it
true
