Chapter 6 Flashcards
Normalization works through a series of stages called normal forms.
True
Normalization produces a lower normal form.
False
In order to meet performance requirements, you may have to denormalize portions of the database design.
True
Denormalization produces a lower normal form.
True
Normalization is a very important database design ingredient and the highest level is always the most desirable.
False
A table is in BCNF if every determinant in the table is a foreign key.
False
A table is in fourth normal form if it is in third normal form and has no independent multivalued dependencies.
True
Relational models view the data as part of a table or collection of tables in which all key values must be identified.
True
Dependency diagrams are very helpful in getting a bird’s-eye view of all the relationships among a table’s attributes.
True
Dependencies that are based on only a part of a composite primary key are called transitive dependencies.
False
All relational tables satisfy the 1NF requirements.
True
Converting a database format from 1NF to 2NF is a complex process.
False
Because 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.
True
A table is in 2NF if it is in 1NF and it includes no partial dependencies.
True
A determinant is any attribute whose value determines other values within a column.
False
A dependency of one nonprime attribute on another nonprime attribute is a partial dependency.
False
Atomic attributes are attributes that can be further subdivided.
False
Normalization represents a micro view of the entities within the ERD.
True
The combination of normalization and ER modeling yields a useful ERD, whose entities may now be translated into appropriate relationship structures.
False
A good relational DBMS excels at managing denormalized relations.
False
Normalization purity is easy to sustain in the modern database environment.
False
Unnormalized database tables often lead to various data redundancy disasters in production databases.
True
Attributes should clearly define participation, connectivity, and document cardinality.
False
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
1NF, 2NF, and 3NF are ____.
normalization stages
____ yields better performance.
denormalization
An attribute that is part of a key is known as a(n) ____ attribute.
prime
A table that displays data redundancies yields ____.
anomalies
Some very specialized applications may require normalization beyond the ____.
4NF
Of the following normal forms, ____ is mostly of theoretical interest.
DKNF
A(n) ____ exists when there are functional dependencies such that Y is functionally dependent on X and Z is functionally dependent on Y, and X is the primary key.
transitive dependency
A ____ derives its name from the fact that a group 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
Dependencies based on only a part of a composite primary key are called ____ dependencies.
partial
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
A table that is in 1NF and includes no partial dependencies is said to be in ____.
2NF
If you have three different transitive dependencies, ____ different determinant(s) exist.
three
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
A table that is in 2NF and contains no transitive dependencies is said to be in ____.
3NF
According to naming conventions described in Chapter 2, ____ would be the best name for a column representing the charges per hour in a table named JOB.
JOB_CHG_HOUR
An atomic attribute ____.
cannot be further subdivided
The most likely data type for a surrogate key is ____.
numeric
Granularity refers to ____.
the level of detail represented by the values stored in a table’s row
In a real-world environment, we must strike a balance between design integrity and ____.
flexibility
For most business transactional databases, we should normalize relations into ____.
3NF
To generate a surrogate key, Microsoft Access uses a(n) ____ data type.
AutoNumber
BCNF can be violated only if the table contains more than one ____ key.
candidate
Most designers consider the BCNF as a special case of the ____.
3NF
A table where all attributes are dependent on the primary key and are independent of each other, and no row contains two or more multivalued facts about an entity, is said to be in ____.
4NF
When designing a database, you should ____.
-make sure entities are in normal form before table structures are created
create table structures then normalize the database
only normalize the database when performance problems occur
consider more important issues such as performance before normalizing
Normalization represents a micro view of the ____ within the ERD.
entities
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 is stored in the table as rows.
temporary
____ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.
data warehouse
Normalization works through a series of stages called normal forms.
true
Normalization is a process that is used for changing attributes to entities.
false
Denormalization produces a lower normal form.
true
A table is in BCNF if every determinant in the table is a candidate key.
true
A table is in fourth normal form if it is in third normal form and has no independent multivalued dependencies.
true
Repeating groups must be eliminated by making sure that each row defines a single entity.
true
Dependencies that are based on only a part of a composite primary key are called transitive dependencies.
false
With partial dependencies, data redundancies occur because every row entry requires duplication of data.
true
Because 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.
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.
true
A dependency of one nonprime attribute on another nonprime attribute is a partial dependency.
false
Normalization should be part of the design process.
true
The combination of normalization and ER modeling yields a useful ERD, whose entities may now be translated into appropriate relationship structures.
false
The advantage of higher processing speed must be carefully weighed against the disadvantage of data anomalies.
true
Unnormalized database tables often lead to various data redundancy disasters in production databases.
true
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
From a structural point of view, 2NF is better than ____.
1NF
An attribute that is part of a key is known as a(n) ____ attribute.
prime
Data redundancy produces ____.
data integrity problems
Of the following normal forms, ____ is mostly of theoretical interest.
DKNF
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 B.
determines
A relational table must not contain a(n) ____.
repeating group
In a(n) ____ diagram, the arrows above the attributes indicate all desirable dependencies.
dependency
A table that is in 1NF and includes no partial dependencies is said to be in ____.
2NF
Before converting a table into 3NF, it is imperative the table already be in ____.
2NF
A table that is in 2NF and contains no transitive dependencies is said to be in ____.
3NF
