MIS 431 ER Modeling Exam #1 Questions with Correct Answers
Entity Relationship Modeling - ✔✔conceptual database modeling technique
(graphical representation)
Main components of ER modeling - ✔✔Entities
Attributes
Relationships
Entities - ✔✔-corresponds to entire table, not row
-represented by rectangle
-every entity has to be related to at least one other entity
Attributes - ✔✔-describes characteristics of entities
-domain is a set of positive values
-primary keys underlined
Relationships - ✔✔how entities relates to each other (foreign keys)
-indicates number of associated entities participating in the relationship
Relational Database - ✔✔designer focuses on logical representation rather than
physical
benefits of relational database - ✔✔-STRUCTURAL AND DATE INDEPENDENCE
-related record stored in independent tables
, -logical simplicity
-allows for more effective design strategies
Tables - ✔✔-holds related entities or entity set
-also called relations
-comprised of rows and columns
Common Notations for ER Modeling - ✔✔-Chen's
-Crow's Feet
-Modeling Language (UML)
Types of Attributes - ✔✔-Simple
-Composite
-Single-valued
-Multi-valued
-Stored
-Derived
Simple attribute - ✔✔cant be further subdivided
ex: first name, last name
Composite attribute - ✔✔can be further subdivided
ex: state, name, city
Entity Relationship Modeling - ✔✔conceptual database modeling technique
(graphical representation)
Main components of ER modeling - ✔✔Entities
Attributes
Relationships
Entities - ✔✔-corresponds to entire table, not row
-represented by rectangle
-every entity has to be related to at least one other entity
Attributes - ✔✔-describes characteristics of entities
-domain is a set of positive values
-primary keys underlined
Relationships - ✔✔how entities relates to each other (foreign keys)
-indicates number of associated entities participating in the relationship
Relational Database - ✔✔designer focuses on logical representation rather than
physical
benefits of relational database - ✔✔-STRUCTURAL AND DATE INDEPENDENCE
-related record stored in independent tables
, -logical simplicity
-allows for more effective design strategies
Tables - ✔✔-holds related entities or entity set
-also called relations
-comprised of rows and columns
Common Notations for ER Modeling - ✔✔-Chen's
-Crow's Feet
-Modeling Language (UML)
Types of Attributes - ✔✔-Simple
-Composite
-Single-valued
-Multi-valued
-Stored
-Derived
Simple attribute - ✔✔cant be further subdivided
ex: first name, last name
Composite attribute - ✔✔can be further subdivided
ex: state, name, city
