Modern Database Management - Chapter 4
A co-dependency is a constraint between two attributes or two sets of attributes.
Answer: FALSE
A composite key consists of only one attribute.
Answer: FALSE
________ is a component of the relational data model included to specify business rules to maintain the integrity of data when they are manipulated.
Data integrity
The relational data model consists of which components?
Data structure, Data integrity, Data manipulation
An alternative name for an attribute is called a(n):
alias.
An understanding of how to merge relations is important because:
all of the above.
A primary key that consists of more than one attribute is called a:
composite key.
An attribute (or attributes) that uniquely identifies each row in a relation is called a:
primary key.
A nonkey attribute is also called a(n):
descriptor.
In the SQL language, the ________ statement is used to make table definitions.
create table
When all multivalued attributes have been removed from a relation, it is said to be in:
first normal form.
The entity integrity rule states that:
no primary key attribute can be null.
A two-dimensional table of data is called a:
relation.
A relation that contains minimal redundancy and allows easy use is considered to be:
well-structured.
A foreign key is a primary key of a relation that also is a primary key in another relation.
Answer: FALSE
In the relational data model, associations between tables are defined through the use of primary keys.
Answer: FALSE
The entity integrity rule states that a primary key attribute can be null.
Answer: FALSE
The primary key of the many side migrates to the one side when transforming a one-to-many relationship.
Answer: FALSE
The relational data model does, at this time, directly support subtype/supertype relationships.
Answer: FALSE
The truncate table statement in SQL creates a new table.
Answer: FALSE
There can be multivalued attributes in a relation.
Answer: FALSE
A candidate key is an attribute, or combination of attributes, that uniquely identifies a row in a relation.
Answer: TRUE
A cascading delete removes all records in other tables associated with the record to be deleted.
Answer: TRUE
A partial functional dependency is a functional dependency in which one or more nonkey attributes are functionally dependent on part (but not all) of the primary key.
Answer: TRUE
A primary key is an attribute that uniquely identifies each row in a relation.
Answer: TRUE
A referential integrity constraint is a rule that maintains consistency among the rows of two relations.
Answer: TRUE
A relation in fifth normal form may not contain any anomalies.
Answer: TRUE
A well-structured relation contains minimal redundancy and allows users to manipulate the relation without errors or inconsistencies.
Answer: TRUE
All values that appear in a column of a relation must be taken from the same domain.
Answer: TRUE
Data structures include data organized in the form of tables with rows and columns.
Answer: TRUE
If an identifier is not assigned, the default primary key for an associative relation consists of the two primary key attributes from the other two relations.
Answer: TRUE
One property of a relation is that each attribute within a relation has a unique name.
Answer: TRUE
Sample data are useful for developing prototype applications and for testing queries.
Answer: TRUE
The allowable range of values for a given attribute is part of the domain constraint.
Answer: TRUE
The columns of a relation can be interchanged without changing the meaning or use of the relation.
Answer: TRUE
View integration is the process of merging relations together.
Answer: TRUE
When a regular entity type contains a multivalued attribute, two relations are created.
Answer: TRUE
When normalizing, the goal is to decompose relations with anomalies to produce smaller, well-structured relations.
Answer: TRUE
When two or more attributes describe the same characteristic of an entity, they are synonyms.
Answer: TRUE
The normal form which removes any remaining functional dependencies because there was more than one primary key for the same nonkeys is called:
Boyce-Codd normal form.
2) Physical database design decisions must be made carefully because of impacts on:
D) all of the above.
9) Which of the following are properties of relations?
Each attribute has a unique name, No two rows in a relation are identical, There are no multivalued attributes in a relation
When a regular entity type contains a multivalued attribute, one must:
create two new relations, one containing the multivalued attribute.
The attribute on the left-hand side of the arrow in a functional dependency is the:
determinant.
A primary key whose value is unique across all relations is called a(n):
enterprise key.
The ________ states that no primary key attribute may be null.
entity integrity rule
An attribute in a relation of a database that serves as the primary key of another relation in the same database is called a:
foreign key.
The normal form which deals with multivalued dependencies is called:
fourth normal form.
A constraint between two attributes is called a(n):
functional dependency.
An attribute that may have more than one meaning is called a(n):
homonym.
A domain definition consists of the following components EXCEPT:
integrity constraints.
All of the following are the main goals of normalization EXCEPT:
maximize storage space.
A functional dependency in which one or more nonkey attributes are functionally dependent on part, but not all, of the primary key is called a ________ dependency.
partial functional
A form of database specification that indicates all the parameters for data storage that are then input to database implementation is:
physical.
A rule that states that each foreign key value must match a primary key value in the other relation is called the:
referential integrity constraint.
Two or more attributes having different names but the same meaning are called:
synonyms.
A candidate key must satisfy all of the following conditions EXCEPT:
the key must indicate the row's position in the table.
A functional dependency between two or more nonkey attributes is called a:
transitive dependency.
Understanding the steps involved in transforming EER diagrams into relations is important because:
you must be able to check the output of a CASE tool.
A relation is in first normal form if it has no more than one multivalued attribute.
Answer: FALSE
A synonym is an attribute that may have more than one meaning.
Answer: FALSE
A transversal dependency is a functional dependency between two or more nonkey attributes.
Answer: FALSE
An anomaly is a type of flaw in the database server.
Answer: FALSE
An enterprise key is a foreign key whose value is unique across all relations.
Answer: FALSE
An identifier assigned to an associative entity is also called a cross-relation key.
Answer: FALSE
Anomalies do not generally arise out of transitive dependencies.
Answer: FALSE
CASE tools can model more complex data relationships, such as ternary relationships.
Answer: FALSE
Data integrity consists of powerful operations to manipulate data stored in relations.
Answer: FALSE
Unlike columns, the rows of a relation may not be interchanged and must be stored in one sequence.
Answer: FALSE
When transforming a one-to-one relationship, a new relation is always created.
Answer: FALSE
When transforming a unary many-to-many relationship to relations, a recursive foreign key is used.
Answer: FALSE
When transforming a weak entity, one should create one relation with both the attributes of the strong entity and the attributes of the weak entity.
Answer: FALSE
17) Which of the following are anomalies that can be caused by redundancies in tables?
Insertion, Deletion, Modification
38) Which of the following anomalies result from a transitive dependency?
Insertion, Deletion, Modification
Which of the following is NOT a reason to create an instance of a relational schema with sample data?
Sample data can reverse database implementation errors.
A relation that contains no multivalued attributes and has nonkey attributes solely dependent on the primary key but contains transitive dependencies is in which normal form?
Second