ISDS 3003 FINAL QUESTIONS & ANSWERS
What do database designs begin with? - answer -verbal or written requirements for the
database
Requirements are formalized as an __________________________ model and then
implemented in _________. - answer -entity-relationship
Sql
An entity-relationship model is - answer -a high-level representation of data
requirements, ignoring implementation details. An entity-relationship model guides
implementation in a particular database system, such as mysql
An entity-relationship model includes three kinds of objects: - answer -- entity
- relationship
- attribute
An entity is - answer -is a person, place, product, concept, or activity.
A relationship is - answer -a statement about two entities
An attribute is - answer -a descriptive property of an entity
What is a reflexive relationship? - answer -a relationship that relates an entity to itself.
Entities, relationships, and attributes are depicted in an - answer -entity-relationship
diagram (er diagram)
How do er diagrams depict entities, relationships, and attributes? - answer -- depicts
entities as rectangles with rounded corners
- relationships as lines connecting rectangles
- attributes within entity rectangles
The full name of a relationship includes the related entities and is written as - answer -
"entity-relationship-entity"
A glossary (also known as a data dictionary or repository) does what? - answer -
documents additional detail in text format
What does a glossary include? - answer -names, synonyms, and descriptions of
entities, relationships, and attributes
Entity type - answer -a set of things
,Ex: all employees in a company
Relationship type - answer -a set of related things
Ex: employee-manages-department is a set of (employee, department) pairs, where the
employee manages the department
Attribute type - answer -a set of values
Ex: all employee salaries
Entity instance - answer -an individual thing
Ex: the employee sam snead.
Relationship instance - answer -a statement about entity instances
Ex: "maria rodriguez manages sales.
Attribute instance - answer -an individual value
Ex: the salary $35,000
Complex databases are developed in three phases: - answer -1. Analysis
2. Logical design
3. Physical design
What happens in analysis? - answer -develops an entity-relationship model, capturing
data requirements while ignoring implementation details
What happens in logical design? - answer -converts the entity-relationship model into
tables, columns, and keys for a particular database system
What happens in physical design? - answer -adds indexes and specifies how tables are
organized on storage media
When is analysis particularly important? - answer -analysis is particularly important for
complex databases with many users when documenting requirements is challenging
Analysis considers implementation issues related to a specific database system
True/false - answer -false
Analysis documents database requirements, without regard to implementation details
for any database system.
An entity-relationship model is developed for all database design projects.
,True/false - answer -false
An entity-relationship model is developed in the analysis phase. Analysis is sometimes
omitted for simple databases with just a few users and tables.
Entities, relationships, and attributes always map directly to tables, foreign keys, and
columns, respectively.
True/false - answer -false
In the logical design phase, entities, relationships, and attributes usually become tables,
foreign keys, and columns. Sometimes, however, an entity splits into several tables,
several entities merge into one table, and relationships and attributes become tables.
What are the 4 analysis steps? - answer -1. Discover entities, relationships, and
attributes
2. Determine cardinality
3. Distinguish strong and weak entities
4. Create supertype and subtype entities
What are the 4 logical design steps? - answer -5. Implement entities
6. Implement relationships
7. Implement attributes
8. Apply normal form
Physical design is dependent on - answer -specific index and table structures, which
vary greatly across relational databases
What parts of speech are entities, relationships, and attributes? - answer -entities are
usually nouns (singular)
Relationships are usually verbs
Attributes are usually nouns that denote specific data, such as names, dates, quantities,
and monetary values.
The first step of the analysis phase - answer -discovery of entities, relationships, and
attributes in interviews and document review
As discovery proceeds, the designer draws an er diagram, determines standard
attribute types, and documents names, synonyms, and descriptions in the glossary.
Cardinality refers to - answer -maxima and minima of relationships and attributes
Relationship maximum - answer -the greatest number of instances of one entity that
can relate to a single instance of another entity
, A relationship has two maxima, one for each of the related entities. Maxima are usually
specified as one or many.
When is a related entity singular or plural? - answer -singular when the maximum is
one
Plural when the maximum is many.
On er diagrams, maximum of one is shown as - answer -a short bar across the
relationship line
Maximum of many is shown as - answer -three short lines that converge at a point
The three lines look like a bird's foot, so this convention is called crow's foot notation.
Relationship minimum - answer -the least number of instances of one entity that can
relate to a single instance of another entity
A relationship has two minima, one for each of the related entities. Minima are usually
specified as zero or one.
When is a related entity optional or required? - answer -a related entity is optional when
the minimum is zero and required when the minimum is one.
On er diagrams, minimum of one is shown as - answer -a short bar across the
relationship line
Minimum of zero is shown as - answer -a circle
Where do maxima and minima symbols appear in relation to the entity? - answer -
maxima symbols always appear next to the entity and minima symbols appear farther
from the entity
Attribute maximum - answer -the greatest number of attribute values that can describe
each entity instance
Attribute maximum is specified as one (singular) or many (plural).
Attribute minimum - answer -the least number of attribute values that can describe
each entity instance. Attribute minimum is specified as zero (optional) or one (required)
In er diagrams, attributes are presumed - answer -singular, optional, not unique
Each value of a unique attribute describes - answer -at most one entity instance
A unique attribute has at most - answer -one entity instance for each attribute value
What do database designs begin with? - answer -verbal or written requirements for the
database
Requirements are formalized as an __________________________ model and then
implemented in _________. - answer -entity-relationship
Sql
An entity-relationship model is - answer -a high-level representation of data
requirements, ignoring implementation details. An entity-relationship model guides
implementation in a particular database system, such as mysql
An entity-relationship model includes three kinds of objects: - answer -- entity
- relationship
- attribute
An entity is - answer -is a person, place, product, concept, or activity.
A relationship is - answer -a statement about two entities
An attribute is - answer -a descriptive property of an entity
What is a reflexive relationship? - answer -a relationship that relates an entity to itself.
Entities, relationships, and attributes are depicted in an - answer -entity-relationship
diagram (er diagram)
How do er diagrams depict entities, relationships, and attributes? - answer -- depicts
entities as rectangles with rounded corners
- relationships as lines connecting rectangles
- attributes within entity rectangles
The full name of a relationship includes the related entities and is written as - answer -
"entity-relationship-entity"
A glossary (also known as a data dictionary or repository) does what? - answer -
documents additional detail in text format
What does a glossary include? - answer -names, synonyms, and descriptions of
entities, relationships, and attributes
Entity type - answer -a set of things
,Ex: all employees in a company
Relationship type - answer -a set of related things
Ex: employee-manages-department is a set of (employee, department) pairs, where the
employee manages the department
Attribute type - answer -a set of values
Ex: all employee salaries
Entity instance - answer -an individual thing
Ex: the employee sam snead.
Relationship instance - answer -a statement about entity instances
Ex: "maria rodriguez manages sales.
Attribute instance - answer -an individual value
Ex: the salary $35,000
Complex databases are developed in three phases: - answer -1. Analysis
2. Logical design
3. Physical design
What happens in analysis? - answer -develops an entity-relationship model, capturing
data requirements while ignoring implementation details
What happens in logical design? - answer -converts the entity-relationship model into
tables, columns, and keys for a particular database system
What happens in physical design? - answer -adds indexes and specifies how tables are
organized on storage media
When is analysis particularly important? - answer -analysis is particularly important for
complex databases with many users when documenting requirements is challenging
Analysis considers implementation issues related to a specific database system
True/false - answer -false
Analysis documents database requirements, without regard to implementation details
for any database system.
An entity-relationship model is developed for all database design projects.
,True/false - answer -false
An entity-relationship model is developed in the analysis phase. Analysis is sometimes
omitted for simple databases with just a few users and tables.
Entities, relationships, and attributes always map directly to tables, foreign keys, and
columns, respectively.
True/false - answer -false
In the logical design phase, entities, relationships, and attributes usually become tables,
foreign keys, and columns. Sometimes, however, an entity splits into several tables,
several entities merge into one table, and relationships and attributes become tables.
What are the 4 analysis steps? - answer -1. Discover entities, relationships, and
attributes
2. Determine cardinality
3. Distinguish strong and weak entities
4. Create supertype and subtype entities
What are the 4 logical design steps? - answer -5. Implement entities
6. Implement relationships
7. Implement attributes
8. Apply normal form
Physical design is dependent on - answer -specific index and table structures, which
vary greatly across relational databases
What parts of speech are entities, relationships, and attributes? - answer -entities are
usually nouns (singular)
Relationships are usually verbs
Attributes are usually nouns that denote specific data, such as names, dates, quantities,
and monetary values.
The first step of the analysis phase - answer -discovery of entities, relationships, and
attributes in interviews and document review
As discovery proceeds, the designer draws an er diagram, determines standard
attribute types, and documents names, synonyms, and descriptions in the glossary.
Cardinality refers to - answer -maxima and minima of relationships and attributes
Relationship maximum - answer -the greatest number of instances of one entity that
can relate to a single instance of another entity
, A relationship has two maxima, one for each of the related entities. Maxima are usually
specified as one or many.
When is a related entity singular or plural? - answer -singular when the maximum is
one
Plural when the maximum is many.
On er diagrams, maximum of one is shown as - answer -a short bar across the
relationship line
Maximum of many is shown as - answer -three short lines that converge at a point
The three lines look like a bird's foot, so this convention is called crow's foot notation.
Relationship minimum - answer -the least number of instances of one entity that can
relate to a single instance of another entity
A relationship has two minima, one for each of the related entities. Minima are usually
specified as zero or one.
When is a related entity optional or required? - answer -a related entity is optional when
the minimum is zero and required when the minimum is one.
On er diagrams, minimum of one is shown as - answer -a short bar across the
relationship line
Minimum of zero is shown as - answer -a circle
Where do maxima and minima symbols appear in relation to the entity? - answer -
maxima symbols always appear next to the entity and minima symbols appear farther
from the entity
Attribute maximum - answer -the greatest number of attribute values that can describe
each entity instance
Attribute maximum is specified as one (singular) or many (plural).
Attribute minimum - answer -the least number of attribute values that can describe
each entity instance. Attribute minimum is specified as zero (optional) or one (required)
In er diagrams, attributes are presumed - answer -singular, optional, not unique
Each value of a unique attribute describes - answer -at most one entity instance
A unique attribute has at most - answer -one entity instance for each attribute value
