database
Which of the following is true? Mapping an M:N relationship that has no attributes will result in:
-A new relation -Two foreign keys -A composite primary key
How many columns will the relation PRODUCT have in the relational schema mapped from the ABC Retailer ER diagram?
3
How many columns will the relation PROMOTION have in the relational schema mapped from the ABC Retailer ER diagram?
3
How many foreign keys in the relational schema mapped from the Central School Library ER diagram serve as a component of a primary key?
3
How many foreign keys will the relational schema mapped from the ABC Retailer ER diagram have?
3
How many foreign keys will the relational schema mapped from the Central School Library ER diagram have?
3
If a 1:M relationship is mandatory on both sides, and if the table resulting from the 1 side has 3 records, then the table resulting from the M side CANNOT have less than ________ records.
3
If a 1:M relationship is mandatory on the M side and optional on the 1 side, and if the table resulting from the 1 side has 3 records, then the table resulting from the M side cannot have less than ________ records.
3
If an M:N relationship is mandatory on both sides, and if both relations resulting from the entities involved in the relationship each have 3 records, then the resulting bridge relation cannot have less than ________ records.
3
If an M:N relationship is mandatory on one side and optional on the other side, and if both relations resulting from the entities involved in the relationship each have 3 records, then the resulting bridge relation cannot have less than ________ records.
3
How many columns will the relation DRIVER have in the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram?
3 or 4
How many columns will the relation TRUCK have in the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram?
3 or 4
An ER diagram that contains two entities involved in two separate M:N relationships will be mapped as how many relations?
4
How many foreign keys will the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram have?
4
How many tables will the relational schema mapped from the ABC Retailer ER diagram have?
4
How many tables will the relational schema mapped from the Central School Library ER diagram have?
4
How many tables will the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram have?
4
What is the minimal number of records that can be entered in the database whose relational schema is mapped from the Eaglerun Trucking Dispatcher ER diagram?
4
What is the minimal number of records that can be entered in the database whose relational schema is mapped from the Central School Library ER diagram?
5
Which of the following (regarding the relation ENROLLMENT. represents the deletion anomaly?
Deleting a student may delete all information about a class
Which of the following functional dependencies does not exist in the table FLIGHT?
FlightID --> NoOfPassengers
Which of the following functional dependencies in the table FLIGHT is an augmented functional dependency?
FlightID, Date --> Origin
Which of the following actions in the table ENROLLMENT will be affected by a modification anomaly?
Changing the name of English1 to English101
Normalizing table FLIGHT and ENROLLMENT to 3NF will result in:
Two separate tables
As a result of mapping the ZYX Company ERD, the resulting relational schema will have a total of two relations.
f
DCL commands are used to manage database transactions.
f
ER modeling is a widely used logical database modeling method.
f
Each weak entity has one owner entity.
f
Entity instances are depicted in ER diagrams.
f
Every ER notation uses the same rule for placement of cardinality constraints in the relationships of the ER diagram.
f
Every normalized database is eventually denormalized.
f
Every relation without transitive functional dependencies is in 3NF. Every relation without partial functional dependencies is in 3NF.
f
For each employee middle initial is optional is an example of an implicit database constraint.
f
If A, B, C, and D are columns of the table whose composite primary key is A, B while C and D are nonkey columns then B --> D is a transitive functional dependency.
f
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0<, then the number of columns in the relational schema resulting from mapping the GENERIC ERD is 5.
f
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0<, then the number of relations in the relational schema resulting from mapping the GENERIC ERD is 2.
f
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0|, then the number of optional columns in the relational schema resulting from mapping the GENERIC ERD is 0.
f
If one of two identical relational tables has the first row moved to the last place, those two relational tables are no longer identical.
f
Maximum cardinality can be optional.
f
Minimum cardinality can be many.
f
Partial functional dependency exists in the table VEHICLE.
f
TCL commands facilitate the process of data access control.
f
Two columns of a relational table can have the same names.
f
Update operations are also referred to as read operations.
f
When an entity has multiple unique attributes, each one of them is mapped as a primary key of the resulting relation.
f
Table VEHICLE is in 3NF
f (it is in 1NF and 2NF)
A multivalued composite attribute can be used to depict which of the following weak entity concepts?
identifying relationship
Table DOCTOR is:
in 3NF (so no changes to make it 3NF)
Relationship attributes may be necessary in a relationship of what type?
many-to-many
Max Cardinality
one or many
Which of the following is a possible type of relationship (maximum cardinality-wise.?
one-to-one
min cardinality
optional or mandatory
What type of functional dependency does NOT exist in the table ENROLLMENT?
partial
Tuple aka
row
Which of the following is a part of a DML statement?
select
A bridge relation is a result of mapping an M:N relationship.
t
A nonkey column is a column in a relation that is not a primary or a candidate key column.
t
A relational schema is a visual depiction of the relational database model.
t
A relationship attribute of a M:N relationship cannot be assigned to either of the entities involved in that relationship.
t
A unary relationship can have one or many maximum cardinalities on either side.
t
A weak entity that has a 1:M identifying relationship with its owner must have a partial key.
t
According to the Eaglerun Trucking Dispatcher ER diagram, we will keep track of the same number of trucks and drivers.
t
Adding a unique attribute to a weak entity converts the weak entity to a regular entity.
t
An entity and its 1:1 unary relationship are mapped as one relation.
t
An entity and its 1:M unary relationship are mapped as one relation.
t
As a result of mapping the ZYX Company ERD into a relational schema, primary key of the relation CUSTOMER will be referred to by a foreign key in the relation CUSTOMER.
t
As a result of mapping the ZYX Company ERD into a relational schema, primary key of the relation EMPLOYEE will be referred to by a foreign key in the relation CUSTOMER.
t
As a result of mapping the ZYX Company ERD, the resulting relational schema will have a total of four foreign keys.
t
As a result of mapping the ZYX Company ERD, the resulting relational schema will have zero bridge tables.
t
Deleting the following record in the table VEHICLE: 222, Car, Ford, O2, Pat while leaving the remaining three records in the table, will cause an occurrence of a deletion anomaly.
t
Each instance of a weak entity must participate in one instance of the identifying relationship.
t
Every attribute appears only once in an ER diagram
t
Every relation is in 1NF.
t
Every relation without partial functional dependencies is in 2NF.
t
If A, B, C, and D are columns of the table whose composite primary key is A, B while C and D are nonkey columns then C --> D is a transitive functional dependency.
t
If A, B, C, and D are columns of the table whose composite primary key is A, B while C and D are nonkey columns then B --> C is a partial functional dependency.
t
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0<, then the number of optional columns in the relational schema resulting from mapping the GENERIC ERD is 0.
t
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is ||, then the number of columns in the relational schema resulting from mapping the GENERIC ERD is 5. If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0|, then the number of columns in the relational schema resulting from mapping the GENERIC ERD is 5.
t
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is ||, then the number of optional columns in the relational schema resulting from mapping the GENERIC ERD is 0.
t
If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is ||, then the number of relations in the relational schema resulting from mapping the GENERIC ERD is 2. If in the GENERIC ERD the Symbol 1 is >| and the Symbol2 is 0<, then the number of relations in the relational schema resulting from mapping the GENERIC ERD is 2.
t
It is possible to join two tables without joining a foreign key column in one table with a primary key column in another table.
t
The relation resulting from mapping a weak entity (with a 1:M identifying relationship. has a composite primary key that is composed of the partial identifier and a foreign key corresponding to the primary key of the owner entity.
t
Two columns of a relational table can have the same values.
t
Two entities can be related via multiple different binary relationships.
t
relation aka
table
What type of functional dependency does NOT exist in the table FLIGHT?
transitive
What type of functional dependency exists in the table DOCTOR?
trivial
An M:N relationship that can have multiple occurrences between the same instances of involved entities can be depicted as a:
weak entity w/ two owners
Which of the following is a part of a DDL statement?
create
Which of the following is true according to the ZYX Company ER diagram?
-An employee can serve one customer or he or she does not have to serve any customers -Each customer is served by exactly one employee -An employee can sign up many customers but he or she does not have to sign up any customers -Each customer is signed up by exactly one employee -We cannot keep track of employees that serve multiple customers -We can keep track of customers that are not referred by any customers
Which of the following is NOT true according to the Central School Library ER diagram?
-Each author has a different AuthorName value
Which of the following is NOT true according to the ZYX Company ER diagram?
-We can keep track of employees that have multiple office phone numbers -Each employee is serving a unique customer
If a 1:M relationship is optional on both sides, and if the table resulting from the 1 side has 3 records, then the table resulting from the M side CANNOT have less than ________ records.
0
If a 1:M relationship is optional on the M side and mandatory on the 1 side, and if the table resulting from the 1 side has 3 records, then the table resulting from the M side CANNOT have less than ________ records.
0
If an M:N relationship is optional on both sides, and if both relations resulting from the entities involved in the relationship each have 3 records, then the resulting bridge relation cannot have less than ________ records.
0
How many bridge tables will the relational schema mapped from the Central School Library ER diagram have?
1
How many bridge tables will the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram have?
1
How many tables in the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram will have composite primary keys?
1
If an entity has three unique attributes, how many primary keys will its mapped relation have?
1
A relation resulting from a weak entity has a non-composite primary key when the identifying relationship is:
1:1
How many columns will the relation AUTHOR have in the relational schema mapped from the Central School Library ER diagram?
2
How many columns will the relation BRAND have in the relational schema mapped from the ABC Retailer ER diagram?
2
How many columns will the relation LIBRARY BOOK have in the relational schema mapped from the Central School Library ER diagram?
2
How many columns will the relation REGION have in the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram?
2
How many foreign keys in the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram serve as a component of a primary key?
2
How many tables in the relational schema mapped from the Central School Library ER diagram will have composite primary keys?
2
How many unique non-primary key columns will the relational schema mapped from the Eaglerun Trucking Dispatcher ER diagram have?
2
What will be the result of the following query on table STUDENT? SELECT COUNT( *) FROM student GROUP BY class HAVING COUNT(*. <3)
2
What will be the result of the following query on table STUDENT? SELECT COUNT( *) FROM student GROUP BY class;
2 and 3
An entity with two multivalued attributes will be mapped as how many relations?
3
How many columns will the relation COPY have in the relational schema mapped from the Central School Library ER diagram?
3
Which of the following is NOT true? Mapping an M:N relationship that has no attributes will result in:
A foreign key in both of the relations mapped from the involved entities
If A --> B is an existing functional dependency, which of the following is an augmented functional dependency?
A, C --> B
Which of the following is in danger of being affected by the deletion anomaly in the table ENROLLMENT?
Class H1, History1
Which of the following actions in the table ENROLLMENT will be prevented by an insertion anomaly?
Entering a new class M1, Math1
Which of the following (regarding the relation ENROLLMENT. represents the modification anomaly?
If a class name changes, it may have to be changed in more than one record
Table FLIGHT is:
In 1NF but not in 2NF
Table ENROLLMENT is:
In 2NF but not in 3NF
Which of the following (regarding the relation ENROLLMENT. represents the insertion anomaly?
Inability to insert a class without adding a student
Which of the following (regarding the relation FLIGHT. represents the insertion anomaly?
Inability to insert a flight without its occurrence
An associative entity is used as an alternative way of depicting:
M:N relationships
An optional attribute occurs only in an entity that is involved in a relationship with optional participation.
f
An optional attribute of an entity is not mapped as a column of a relation.
f
Which of the following is a read operation?
Retrieving data from the relation
If a 1:M relationship is optional on both sides, which of the following is true?
The resulting foreign key can have null (empty. values
If a 1:M relationship is optional on the 1 side and mandatory on the M side, which of the following is true?
The resulting foreign key can have null (empty. values
If a 1:M relationship is mandatory on the 1 side and optional on the M side, which of the following is true?
The resulting foreign key cannot have null (empty. values
Every relation contains:
Trivial functional dependency & Full key functional dependency
If A --> B and B --> A are existing functional dependencies, which of the following are NOT equivalent functional dependencies?
X --> A and A --> B
Which of the following statements would be used to drop a column from the table?
alter table
A foreign key column must have the same name as the primary key column it refers to.
f
A relationship attribute of a 1:N relationship cannot be assigned to either of the entities involved in that relationship.
f
A relationship of degree 3 (also known as a ternary relationship. depicts 3 or more entities involved in one relationship.
f
A row of a relation can have in its column two values from the column's domain.
f
A ternary relationship can always be depicted as three binary relationships.
f
A unary relationship cannot have mandatory participation on both sides.
f
A weak entity that has a 1:1 identifying relationship with its owner, must have a partial key.
f
According to the Eaglerun Trucking Dispatcher ER diagram, a driver can drive two trucks.
f
According to the Eaglerun Trucking Dispatcher ER diagram, a truck can be owned by multiple drivers.
f
According to the Eaglerun Trucking Dispatcher ER diagram, each driver owns a truck.
f
According to the Eaglerun Trucking Dispatcher ER diagram, every region must be served by multiple trucks.
f
An entity and its M:N unary relationship are mapped as one relation.
f
An insertion anomaly occurs when a user who wants to insert data about one real world entity is forced to enter a unique value about it.
f
