MIS 3140 FINAL EXAM REVIEW
Superkey - Answers - an attrivute or combination of attributes that uniqely identify each
row in a table
Candidite key - Answers - a minimal superkey, a superkey that does not contain a
subset of attributes that is itself a superkey
Primary key - Answers - a candidate key selected to uniqely identify all other attribute
values in any given row, cannot contain nulls
foreign - Answers - primary key of a foreign table in a relationship with another table
Union - Answers - combines all rows from two tables exluding duplicates. tables must
have same attributes
Intersection - Answers - yeilds only the rows that appear in both tables. must be union
combatble
Product - Answers - product yields all possible pairs of rows from two tables. 6x3 = 18
Divide - Answers - divides table by another table. Dividing LOC by A and B, 5 is only
value associated with A and B
Select - Answers - provides where agent codes are equal, eliminates rest of tables
Project - Answers - eliminates duplicates from select
Data redudancies - Answers - foriegn keys control data redudancy.
Index - Answers - orederly arrangment used to logically access rows in tables. basically
a table of context for a database
Data Dictionairy - Answers -
Entities and Attributes - Answers - Entities are objects/nouns. Attributes are
characteristics of the entity
Relationships, Connectivity, Cardinility - Answers - relationships show association
between entitites
cardianlities are (1,4) connectities are symbols
Existance-dependant - Answers - entity that can exist in the database only when
another entity occurs. employee claims dependant
, relational strength - Answers - a weak relationship occurs exists if the primary key of the
related entity doesnt contain a component of the parent entity.
a strong relationship the entities primary contains the foreign key
Weak entities - Answers - 1. the entity is existance dependent, it cannot exist without
the entity which it has a relationship with
2. the entity has a primary key that is patrially or totally derived from the parent entity of
the relationship
Relationship participation - optional/mandotory - Answers - optional - some courses do
not generate a class
mandotory - one entity requires a corresponding entity in a particular relationship
Relationship degree - Answers - Unary - relationship with its own entity, employee dates
another employee
binary - 2 entities
ternary - association between 3 entities
Recursive relationship - Answers - employee manages employee
composite entities - Answers - associative entity, they solve 1:m relationships. Enroll
table with course and class relationship.
Database design conflicting goals - Answers - processing speed, information
requirements, design standards
Entity supertypes and subtypes - Answers - supertypes is a generic entity type that is
related to one or more entity subtypes
Specilization Hierarchy - Answers - how supertypes and subtypes are arranged.
Parents on top, children on bottom
Inheritance - Answers - enables a subtype to inherit the attributes and relationships of a
supertype
Subtype discriminator - Answers - is the attribute in the supertype entity that determines
to which a subtype the supertype occurence is related
Disjoint/ Overlapping Contraints - Answers - Disjoint - Grad, undergrad
Superkey - Answers - an attrivute or combination of attributes that uniqely identify each
row in a table
Candidite key - Answers - a minimal superkey, a superkey that does not contain a
subset of attributes that is itself a superkey
Primary key - Answers - a candidate key selected to uniqely identify all other attribute
values in any given row, cannot contain nulls
foreign - Answers - primary key of a foreign table in a relationship with another table
Union - Answers - combines all rows from two tables exluding duplicates. tables must
have same attributes
Intersection - Answers - yeilds only the rows that appear in both tables. must be union
combatble
Product - Answers - product yields all possible pairs of rows from two tables. 6x3 = 18
Divide - Answers - divides table by another table. Dividing LOC by A and B, 5 is only
value associated with A and B
Select - Answers - provides where agent codes are equal, eliminates rest of tables
Project - Answers - eliminates duplicates from select
Data redudancies - Answers - foriegn keys control data redudancy.
Index - Answers - orederly arrangment used to logically access rows in tables. basically
a table of context for a database
Data Dictionairy - Answers -
Entities and Attributes - Answers - Entities are objects/nouns. Attributes are
characteristics of the entity
Relationships, Connectivity, Cardinility - Answers - relationships show association
between entitites
cardianlities are (1,4) connectities are symbols
Existance-dependant - Answers - entity that can exist in the database only when
another entity occurs. employee claims dependant
, relational strength - Answers - a weak relationship occurs exists if the primary key of the
related entity doesnt contain a component of the parent entity.
a strong relationship the entities primary contains the foreign key
Weak entities - Answers - 1. the entity is existance dependent, it cannot exist without
the entity which it has a relationship with
2. the entity has a primary key that is patrially or totally derived from the parent entity of
the relationship
Relationship participation - optional/mandotory - Answers - optional - some courses do
not generate a class
mandotory - one entity requires a corresponding entity in a particular relationship
Relationship degree - Answers - Unary - relationship with its own entity, employee dates
another employee
binary - 2 entities
ternary - association between 3 entities
Recursive relationship - Answers - employee manages employee
composite entities - Answers - associative entity, they solve 1:m relationships. Enroll
table with course and class relationship.
Database design conflicting goals - Answers - processing speed, information
requirements, design standards
Entity supertypes and subtypes - Answers - supertypes is a generic entity type that is
related to one or more entity subtypes
Specilization Hierarchy - Answers - how supertypes and subtypes are arranged.
Parents on top, children on bottom
Inheritance - Answers - enables a subtype to inherit the attributes and relationships of a
supertype
Subtype discriminator - Answers - is the attribute in the supertype entity that determines
to which a subtype the supertype occurence is related
Disjoint/ Overlapping Contraints - Answers - Disjoint - Grad, undergrad
