Chapter 6
Normalization is a very important database design ingredient and the highest level is always the most desirable. (T/F)
,False
In the context of partial dependencies data redundancies occur because every row entry requires duplication of data. (T/F)
,True
It is possible for a table in 2NF to exhibit transitive dependency where the primary key may rely on one or more nonprime attributes to functionally determine other nonprime attributes. (T/F)
,True
Since a partial dependency can exist only if a table's primary key is composed of several attributes if a table in 1NF has a single-attribute primary key, then the table is automatically in 2NF. (T/F)
,True
A table that has all key attributes defined has no repeating groups, and all its attributes are dependent on the primary key is said to be in ______.
1NF
From a structural point of view 2NF is better than _______
1NF
Data warehouse routinely uses ______ structures in its complex multilevel, multisource data environment.
2NF
From a structural point of view 3NF is better than ____
2NF
A table that is in 2NF and contains no transitive dependencies is said to be in _____
3NF
For most business transactional databases we should normalize relations into _______
3NF
A table where all attributes are dependent on the primary key but are independent of each other and no row contains two or more multivalued facts about an entity is said to be in ____.
4NF
Some very specialized applications may require normalization beyond the _____
4NF
To generate a surrogate key Microsoft Access uses a(n) _______ data type
AutoNumber
A table where every determinant is a candidate key is said to be in _____
BCNF
Of the following normal forms, ______ is mostly of theoretical interest.
DKNF
_______ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.
Data warehouse
Attribute A ______ attribute B if all of the rows in the table that agree in value for attribute A also agree in value for attribute.
Determines.
A dependency of one nonprime attribute on another nonprime attribute is a partial dependency. (T/F)
False
A determinant is any attribute whose value determines other values within a column. (T/F)
False
A good relational DBMS excels at managing denormalized relations. (T/F)
False
A table is in BCNF if every determinant in the table is a foreign key (T/F)
False
Atomic attributes are attributes that can be further subdivided. (T/F)
False
Attributes should clearly define participation connectivity, and document cardinality. (T/F)
False
Data stored at their highest level of granularity are said to be atomic data. (T/F)
False
Dependencies that are based on only a part of a composite primary key are called transitive dependencies. (T/F)
False
Normalization is a process that is used for changing attributes to entities. (T/F)
False
Normalization purity is often easy to sustain in the modern database environment. (T/F)
False
Reporting anomalies in a table can cause a multitude of problems for managers and can be fixed through application programming. (T/F)
False
A table is in 4NF if it is in 3NF and ____ .
It has no multivalued dependencies
Normalization works through a series of stages called normal forms. For most purposes in business database design, _____ stages are as high as you need to go in the normalization process.
Three
A table is in fourth normal form if it is in third normal form and has no independent multivalued dependencies. (T/F)
True
All relational tables satisfy the 1NF requirements. (T/F)
True
Data redundancy produces data anomalies. (T/F)
True
Denormalization produces a lower normal form. (T/F)
True
Dependency diagrams are very helpful in getting a bird'seye view of all the relationships among a table's attributes. (T/F)
True
In order to meet performance requirements portions of the database design may need to be occasionally denormalized. (T/F)
True
Normalization represents a micro view of the entities within the ERD. (T/F)
True
Normalization works through a series of stages called normal forms. (T/F)
True
Relational models view data as part of a table or collection of tables in which all key values must be identified. (T/F)
True
Repeating groups must be eliminated by ensuring that each row defines a single entity. (T/F)
True
The advantage of higher processing speed must be carefully weighed against the disadvantage of data anomalies. (T/F)
True
The combination of normalization and ER modeling yields a useful ERD whose entities can be translated into appropriate relationship structures (T/F)
True
The objective of normalization is to ensure that each table conforms to the concept of well-formed relations. (T/F)
True
Unnormalized database tables often lead to various data redundancy disasters in production databases (T/F)
True
A table that displays data redundancies yields ____.
anomalies
Improving _____ leads to more flexible queries.
atomicity
BCNF can be violated only if the table contains more than one ________ key.
b. candidate
An atomic attribute _____ .
cannot be further subdivided
The conflicts between design efficiency information requirements, and performance are often resolved through_____.,
compromises that include denormalization
Data redundancy produces ____.
data integrity problems
In a(n) ________ diagram the arrows above the attributes indicate all desirable dependencies.
dependency
From a system functionality point of view, _________ attribute values can be calculated when they are needed to write reports or invoices
derived
In a real-world environment we must strike a balance between design integrity and ______
flexibility
In a _____ situation one key determines multiple values of two other attributes and those attributes are independent of each other
multivalued dependency
The most likely data type for a surrogate key is _____.
numeric
Dependencies based on only a part of a composite primary key are known as ________ dependencies.
partial
If a table has multiple candidate keys and one of those candidate keys is a composite key the table can __________ have based on this composite candidate key even when the primary key chosen is a single attribute.
partial dependencies
An attribute that is part of a key is known as a(n) ______ attribute.
prime
A _________ derives its name from the fact that a collection of multiple entries of the same type can exist for any single key attribute occurrence.
repeating group
A relational table must not contain a(n) _____.
repeating group
An example of denormalization is using a _______ denormalized table to hold report data. This is required when creating a tabular report in which the columns represent data that are stored in the table as rows.
temporary
When a table contains only one candidate key, _________ are considered to be equivalent.
the 3NF and the BCNF
Granularity refers to ______
the level of detail represented by the values in a table's row
A(n) _____ exists when there are functional dependencies such that Y is functionally dependent on X, Z is functionally dependent on Y, and X is the primary key.
transitive dependency
