Modern Database Management Chapter 4 (12th edition) – Flashcards
Unlock all answers in this set
Unlock answersquestion
Alias
answer
An alternative name used for an attribute
question
Anomaly
answer
An error or inconsistency that may result when a user attempts to update a table that contains redundant data. The three types of anomalies are insertion, deletion and modification anomalies
question
Candidate Key
answer
An attribute, or combination of attributes, that uniquely identifies a row in a relation
question
Composite Key
answer
A primary key that consists of more than one attribute
question
Determinant
answer
The attribute on the left side of the arrow in a functional dependency
question
Enterprise Key
answer
A primary key whose value is unique across all relations
question
Entity integrity rule
answer
A rule that states that no primary key attribute (or component of a primary key attribute) may be null
question
First normal form (1NF)
answer
A relation that has a primary key and in which there are no repeating groups.
question
Foreign Key
answer
An attribute in a relation that serves as the primary key of another relation in the same database
question
Functional dependency
answer
A constraint between two attributes in which the value of one attribute is determined by the value of another attribute
question
Homonym
answer
An attribute that may have more than one meaning
question
Normal form
answer
A state of relation that requires that certain rules regarding relationships between attributes (or functional dependencies) are satisfied
question
Normalization
answer
The process of decomposing relations with anomalies to produce smaller, well-structured relations.
question
Null
answer
A value that may be assigned to an attribute when no other value applies or when the applicable value is unknown
question
Partial functional dependency
answer
A functional dependency in which one or more nonkey attributes are functionally dependent on part (but not all) of the primary key.
question
Primary Key
answer
An attribute or combination of attributes that uniquely identifies each row in a relation
question
Recursive foreign key
answer
A foreign key in a relation that references the primary key values of the same relation
question
Referential integrity constraint
answer
A rule that states that either each foreign key value must match a primary key value in another relation or the foreign key value must be null
question
Relation
answer
A named two-dimensional table of data
question
Second normal form (2NF)
answer
A relation in first normal form in which every nonkey attribute is fully functionally dependent on the primary key
question
Surrogate primary key
answer
A serial number or other system-assigned primary key for a relation
question
Synonyms
answer
Two (or more) attributes that have different names but the same meaning
question
Third normal form (3NF)
answer
A relation that is in second normal form and has no transitive dependencies
question
Transitive dependency
answer
A functional dependency between the primary key and one or more nonkey attributes that re dependent on the primary key via another nonkey attribute
question
Well-structured relation
answer
A relation that contains minimal redundancy and allows users to insert, modify, and delete the rows in a table without errors or inconsistencies
