FINAL EXAM

A relationship attribute of a 1:N relationship can be assigned to the entity on the 1 side of that relationship, and the ER diagram would still have the same meaning.

FALSE

Every ER notation uses the same rule for placement of cardinality constraints in the relationships of the ER diagram.

False

A weak entity that has a 1:M identifying relationship with its owner must have a partial key.

True

The following attribute represents a collection of attributes:

Composite attribute

A unary relationship cannot have mandatory participation on both sides.

False

Maximum cardinality can be optional.

False

A relationship attribute of a 1:N relationship can be assigned to the entity on the N side of that relationship, and the ER diagram would still have the same meaning.

TRUE

An M:N relationship that can have multiple occurrences between the same instances of involved entities can be depicted as a:

Weak entity

Exact maximum cardinality is calculated by adding the exact minimum cardinalities.

False

An associative entity is used as an alternative way of depicting:

M:N relationships

ER modeling is a widely used logical database modeling method.

False

Which of the following is a legitimate exact minimum and maximum cardinality?

(5, 10)

Components of a unique composite attribute are not unique.

True

A unary relationship can have one or many maximum cardinalities on either side.

True

What type of ternary relationship CANNOT be depicted as two binary relationships?

Many-to-many-to-many

A regular entity must have at least one of the following attributes:

Unique attribute

Which of the following is NOT a possible cardinality constraint?

Optional zero

Two entities can be related via multiple different binary relationships.

True

How many entities are involved in a binary relationship?

2

A relationship attribute of a M:N relationship can be assigned to either of the entities involved in that relationship, and the ER diagram would still have the same meaning.

FALSE

What is depicted by ER Diagrams?

Metadata only

How many entities are depicted by the following requirements? \n School XYZ keeps track of its 100 students, 10 teachers, and 5 classrooms.

3

How many entities are involved in a unary relationship?

1

A weak entity that has a 1:1 identifying relationship with its owner, must have a partial key.

False

Adding a unique attribute to a weak entity converts the weak entity to a regular entity.

True

An optional attribute occurs only in an entity that is involved in a relationship with optional participation.

False

Relationship instances occur when an instance of one entity is related to an instance of another entity via a relationship.

True

A ternary relationship can always be depicted as three binary relationships.

False

Entity instances are depicted in ER diagrams.

False

Each instance of a weak entity must participate in exactly one instance of the identifying relationship.

True

In an ER diagram, each entity is always connected to all of the other entities, either via a direct relationship or indirectly via other entities and relationships.

True

The values of the following attribute are NOT permanently stored in a database.

Derived attribute

Minimum cardinality can be many.

False

Which of the following is a possible type of relationship (maximum cardinality-wise)?

One-to-one

The following attribute can contain more than one value for each entity instance.

Multivalued attribute

A relationship of degree 3 (also known as a ternary relationship) depicts 3 entities involved in one relationship.

TRUE

Relationship attributes may be necessary in a relationship of what type?

Many-to-many

Maximum cardinality can be:

One or many

Within one entity, each attribute name must be different.

True

Within an ER diagram that contains multiple entities, each entity must be related to at least one other entity via a relationship.

True

Minimum cardinality can be:

Optional or mandatory

A unique attribute is an attribute whose value is different for each entity instance.

TRUE

A multivalued composite attribute can be used to depict which of the following weak entity concepts?

Identifying relationship

An attribute can be a part of several composite attributes.

True

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 \n

3

Two columns of a relational table can have the same values. \n

TRUE

Which of the following is NOT true? In a relational database: \n

Two tables, in the same database, can have the same name

Every attribute appears only once in an ER diagram \n

True

An ER diagram that contains two entities involved in two separate M:N relationships will be mapped as how many relations?

4

\n A relation resulting from a weak entity has a non-composite primary key when the identifying relationship is:

1:1

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

3

Within one relation, two rows can be identical.

False

Two columns of two different tables in the same relational database can have the same names.

True

Two columns of a relational table can have the same names.

False

When an entity has multiple unique attributes, each one of them is mapped as a primary key of the resulting relation.

False

A foreign key column must have the same name as the primary key column it refers to.

False

\n Autonumber data type option:

Enables automatic generation of consecutive numeric data values in a column

An entity and its 1:1 unary relationship are mapped as one relation.

True

A relational schema is a visual depiction of the relational database model.

True

\n 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 an entity has three unique attributes, how many primary keys will its mapped relation have?

1

If in one of two identical relational tables the first row is moved to the last place, those two relational tables are no longer identical.

False

Tuple is a synonym for

Row

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.

True

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

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. \n

0 (no records required)

A restriction specifying that no salary entered in the salary column can be higher than $300,000 is an example of a business rule.

True

If a 1:M relationship is mandatory on both sides, which of the following is true? \n

The resulting foreign key cannot have null (empty) values

An entity and its M:N unary relationship are mapped as one relation.

False

Relation is a synonym for the following construct in a relational database

\n Table

If in one of two identical relational tables the last column moved to the first place, those two relational tables are no longer identical. \n

False

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. \n

3 \n

Within one column, one row of a relation can contain two values from that column's domain.

False

For each employee, middle initial is optional is an example of an implicit database constraint.

False

What is depicted by relational schemas?

Metadata only \n

If a 1:M relationship is optional on the 1 side and mandatory on the M side, which of the following is true? \n

The resulting foreign key can have null (empty) values

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 (no records required)

An entity in an ERD that contains two multivalued attributes will result in how many relations when mapped into a relational schema?

3

Which of the following is true? In a relational table: \n

Two columns can have identical values (i.e. same values in each row of those two columns)

An optional attribute of an entity is not mapped as a column of a relation.

False

A bridge relation is a result of mapping an M:N relationship.

True

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. \n

\n 0 (no records required)

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. \n

3

Which of the following is NOT true? Mapping a binary M:N relationship will result in:

A foreign key in both of the relations mapped from the involved entities

An entity and its 1:M unary relationship are mapped as one relation. \n

true

Which of the following statements regarding the table below is true? \n ColumnAColumnBColumnC

Every combination of values in Column A and Column B within the same row is unique

Each weak entity has exactly one owner entity.

False

If P --\> Q and Q --\> P are existing functional dependencies, which of the following are equivalent functional dependencies?

none of the above

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 would be a transitive functional dependency.

False

Normalizing table FLIGHT to 3NF will result in:

Two separate tables

Which of the following is in danger of being affected by the deletion anomaly in the table ENROLLMENT (with its current 3 records)?

Major H, History (WRONG)

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.

False

Which of the following actions in the table ENROLLMENT will be prevented by an insertion anomaly?

Entering a new major M, Math

Every 3NF database can be further streamlined by including designer-added tables and keys.

False

Every relation contains:

Full key functional dependency

Which of the following (regarding the relation ENROLLMENT) represents the modification anomaly?

If a major name changes, it may have to be changed in more than one record

What type of functional dependency does NOT exist in the table ENROLLMENT?

Partial

Table FLIGHT is:

In 1NF but not in 2NF

A nonkey column is a column in a relation that is not a primary or a candidate key column.

True

Update operations are also referred to as read \n operations.

False