ACG 4401 EXAM 2 VERIFIED STUDY GUIDE
Conceptual model - Answers - depicts important objects and relationships between
objects that must be captured in a database.
REA Communication methods - Answers - 1. Narrative Description
2. Diagrams with various notations
3. Structured Grammar
4. Predicate logic notation
5. Tags: XML XBRL
6. Programming Language notation
Unified Modeling Language (UML) - Answers - A standard format for communicating
and documenting software design.
Uses diagrams for different analysis levels.
Logical Model - Answers - Shows what a system must do, regardless of how it will be
implemented physically.
independent software, convert conceptual model.
Physical database - Answers - created based on specific database software packages,
database is implemented and dependent on software.
Entity - Answers - real world object with separate existence
Class - Answers - entities with shared characteristics
Association - Answers - Relationship between classes
Association Class - Answers - represents a relationship in which there can be only one
link between the related entities
Reified association - Answers - a relationship in which there can be multiple links
between the related entities
Attribute - Answers - characteristic possessed by a class or association
Primary Key Attribute - Answers - used to uniquely and universally describe each
instance of a class or association class
Concatenated primary key - Answers - a unique and universal identifier for a class or
association class that is made up of multiple attributes
Simple attribute - Answers - An attribute that cannot be subdivided into meaningful
components.
, composite Attributes - Answers - can be divided into smaller subparts, which represent
more basic attributes that have their own meanings
Derivable attribute - Answers - a characteristic of a class or an association class that
can be calculated based on the values of other stored characteristics
Static derivable attribute - Answers - a derivable attribute for which the derived value will
not change if additional transaction data is entered into the database
volatile derivable attribute - Answers - a derivable attribute for which the derived value
will change if additional transaction data is entered into the database
minimum multiplicity - Answers - represents the minimum number of times an instance
of a class must participate in an association with instances of a related class; legal
values are 0 and 1
Optional participation - Answers - one entity occurrence does not require a
corresponding entity occurrence in a particular relationship
0 minimum multiplicity
Relational Model - Answers - Codd:
set theory and predicate logic
Relation - Answers - 2 dimensional storage structure ex: table
Relation Columns - Answers - intension, schema, field rep attribute
Relation Row - Answers - table extension, tuple records, instance of class
Foreign Key - Answers - A primary key of one table that appears as an attribute in
another table and acts to provide a logical relationship between the two tables
Referential Integrity - Answers - A set of rules that Access uses to ensure that the data
between related tables is valid. Must be Null or match data from attribute.
Entity Integrity - Answers - The property of a relational table that guarantees each entity
has a unique value in a primary key and that the key has no null values.
Fact - Answers - pairing of a candidate key attribute value with another attribute value.
Candidate Key - Answers - An attribute, or combination of attributes, that uniquely
identifies a row in a relation.
Could be used as a primary key for a class.
Redundancy - Answers - Duplication of an element within a system.
Conceptual model - Answers - depicts important objects and relationships between
objects that must be captured in a database.
REA Communication methods - Answers - 1. Narrative Description
2. Diagrams with various notations
3. Structured Grammar
4. Predicate logic notation
5. Tags: XML XBRL
6. Programming Language notation
Unified Modeling Language (UML) - Answers - A standard format for communicating
and documenting software design.
Uses diagrams for different analysis levels.
Logical Model - Answers - Shows what a system must do, regardless of how it will be
implemented physically.
independent software, convert conceptual model.
Physical database - Answers - created based on specific database software packages,
database is implemented and dependent on software.
Entity - Answers - real world object with separate existence
Class - Answers - entities with shared characteristics
Association - Answers - Relationship between classes
Association Class - Answers - represents a relationship in which there can be only one
link between the related entities
Reified association - Answers - a relationship in which there can be multiple links
between the related entities
Attribute - Answers - characteristic possessed by a class or association
Primary Key Attribute - Answers - used to uniquely and universally describe each
instance of a class or association class
Concatenated primary key - Answers - a unique and universal identifier for a class or
association class that is made up of multiple attributes
Simple attribute - Answers - An attribute that cannot be subdivided into meaningful
components.
, composite Attributes - Answers - can be divided into smaller subparts, which represent
more basic attributes that have their own meanings
Derivable attribute - Answers - a characteristic of a class or an association class that
can be calculated based on the values of other stored characteristics
Static derivable attribute - Answers - a derivable attribute for which the derived value will
not change if additional transaction data is entered into the database
volatile derivable attribute - Answers - a derivable attribute for which the derived value
will change if additional transaction data is entered into the database
minimum multiplicity - Answers - represents the minimum number of times an instance
of a class must participate in an association with instances of a related class; legal
values are 0 and 1
Optional participation - Answers - one entity occurrence does not require a
corresponding entity occurrence in a particular relationship
0 minimum multiplicity
Relational Model - Answers - Codd:
set theory and predicate logic
Relation - Answers - 2 dimensional storage structure ex: table
Relation Columns - Answers - intension, schema, field rep attribute
Relation Row - Answers - table extension, tuple records, instance of class
Foreign Key - Answers - A primary key of one table that appears as an attribute in
another table and acts to provide a logical relationship between the two tables
Referential Integrity - Answers - A set of rules that Access uses to ensure that the data
between related tables is valid. Must be Null or match data from attribute.
Entity Integrity - Answers - The property of a relational table that guarantees each entity
has a unique value in a primary key and that the key has no null values.
Fact - Answers - pairing of a candidate key attribute value with another attribute value.
Candidate Key - Answers - An attribute, or combination of attributes, that uniquely
identifies a row in a relation.
Could be used as a primary key for a class.
Redundancy - Answers - Duplication of an element within a system.
