Quiz 2 - The Relational Data Model and Relational Database Constraints

Quiz on The Relational Data Model and Relational Database Constraints

By the Open Book Team

Disclaimer

This quiz is not from previouses, and may contain some errors.

What are rows called in the Relational data model?
A. Tuples
B. Entities
C. Columns
D. Attributes

A. Tuples

What is the column header called in the Relational data model?
A. Rows
B. Entities
C. Attributes
D. Tuples

C. Attributes

What is the order of importance in rows in the Relational data model?
A. Important
B. Does not matter
C. Irrelevant
D. Significant

B. Does not matter

What is the order of importance in columns in the Relational data model?
A. Does not matter
B. Important
C. Irrelevant
D. Significant

B. Important

What type of attributes are all attributes (column headers) in the relational model?
A. Composite and multivalued
B. Single-valued and atomic
C. Multivalued and atomic
D. Composite and single-valued

B. Single-valued and atomic

What is a row in the relational model considered?
A. Tuple
B. Entity
C. Attribute
D. Table

B. Entity

What is a Database Schema?
A. A set of rows
B. A set of columns
C. A design for a database that defines its tables, fields, relationships, and other elements
D. A specific table

C. A design for a database that defines its tables, fields, relationships, and other elements

What is the Degree of a relation in the relational model?
A. The number of rows
B. The number of columns
C. The set of valid values
D. The design of a database

B. The number of columns

What is the count of rows known as in the relational model?
A. Domain
B. Degree
C. Cardinality
D. Schema

C. Cardinality

What is the term for the current data stored in a database, encompassing the entirety of information at a specific moment?
A. Database State
B. Database Schema
C. Database Design
D. Database Entity

A. Database State

What changes when adding a new row to a table?
A. Schema and state change
B. Only schema changes
C. Only state changes
D. Neither schema nor state changes

C. Only state changes

What changes when adding a new column to a table?
A. Only state changes
B. Only schema changes
C. Both schema and state change
D. Neither schema nor state changes

C. Both schema and state change

What happens to the schema when any edit is made to a table?
A. It remains the same
B. It changes
C. It becomes irrelevant
D. It becomes inconsistent

B. It changes

What is a Super Key?
A. An attribute that identifies a tuple
B. A unique attribute that identifies a tuple
C. A combination of two or more attributes in a database table
D. A unique combination of two or more attributes in a database table

B. A unique attribute that identifies a tuple

What may a Super Key contain?
A. Only required attributes
B. All attributes except the unique one
C. Additional attributes that are not required for unique identification
D. A single column

C. Additional attributes that are not required for unique identification

What is a Composite Key?
A. A unique attribute that identifies a tuple
B. A combination of two or more attributes in a database table
C. A combination of all attributes in a database table
D. A single column

B. A combination of two or more attributes in a database table

What is a Candidate Key?
A. A Super Key that is minimal
B. A Composite Key that is minimal
C. A unique combination of two or more attributes in a database table
D. A combination of two or more irrelevant attributes

A. A Super Key that is minimal

What is a Primary Key?
A. A Candidate Key with a null value
B. A unique combination of two or more attributes
C. A special type of Candidate Key chosen to uniquely identify tuples
D. An attribute that establishes a link between two tables

C. A special type of Candidate Key chosen to uniquely identify tuples

What is a characteristic of a Primary Key?
A. Can have a null value
B. Must be unique for each tuple
C. Is not underlined in a database schema
D. Cannot be used as a reference to identify tuples

B. Must be unique for each tuple

How are the attributes of the Primary Key represented in a database schema?
A. Italicized
B. Bold
C. Underlined
D. Strikethrough

C. Underlined

What is the purpose of a Primary Key in relation to Foreign Keys?
A. It serves as a reference to identify tuples from another tuple
B. It allows null values in the table
C. It establishes a link between two tables
D. It uniquely identifies Candidate Keys

A. It serves as a reference to identify tuples from another tuple

What is a Secondary/Alternate Key?
A. A unique combination of two or more attributes
B. A Candidate Key with a null value
C. Candidate Keys other than the Primary Key
D. An attribute that establishes a link between two tables

C. Candidate Keys other than the Primary Key

What is a Unique Key?
A. A Primary Key
B. A Candidate Key with a null value allowed
C. A Secondary/Alternate Key
D. A combination of irrelevant attributes

B. A Candidate Key with a null value allowed

What is a Foreign/Reference Key?
A. An attribute that establishes a link between two tables
B. A Primary Key
C. A unique combination of two or more attributes
D. A Candidate Key with a null value allowed

A. An attribute that establishes a link between two tables

What is the nature of Inherent or Implicit Constraints?
A. Imposed by application developers
B. Imposed by the nature of the data model itself
C. Imposed by external applications
D. Imposed by users

B. Imposed by the nature of the data model itself

Where do Inherent or Implicit Constraints originate from?
A. External sources
B. Application developers
C. The data model itself
D. End users

C. The data model itself

What is an example of an Inherent Constraint in the relational model?
A. A list can be a value for any attribute
B. Each attribute should contain a single value
C. Attributes can have null values
D. Foreign Keys are not allowed

B. Each attribute should contain a single value

What type of constraints are expressed within the schema using the features provided by the data model?
A. Inherent or Implicit Constraints
B. Schema-based or Explicit Constraints
C. Application-based or Semantic Constraints
D. Foreign Key Constraints

B. Schema-based or Explicit Constraints

What is an example of a Schema-based or Explicit Constraint?
A. A rule stating that a department cannot have more than 10 employees
B. Each attribute should contain a single value
C. Values in a particular column or combination of columns must be unique
D. A list cannot be a value for any attribute

C. Values in a particular column or combination of columns must be unique

What type of constraints ensure that a certain attribute or combination of attributes uniquely identifies each record in a table?
A. Unique constraints
B. Primary key constraints
C. Foreign key constraints
D. Check constraints

B. Primary key constraints

What type of constraints establish relationships between tables, linking the primary key of one table to a foreign key in another?
A. Unique constraints
B. Primary key constraints
C. Foreign key constraints
D. Check constraints

C. Foreign key constraints

What type of constraints ensure that values in a particular column or combination of columns are unique across all records in a table?
A. Unique constraints
B. Primary key constraints
C. Foreign key constraints
D. Check constraints

A. Unique constraints

What type of constraints allow the definition of rules that values in a column must adhere to?
A. Unique constraints
B. Primary key constraints
C. Foreign key constraints
D. Check constraints

D. Check constraints

What type of constraints go beyond the expressive power of the data model and must be specified and enforced by application programs?
A. Inherent or Implicit Constraints
B. Schema-based or Explicit Constraints
C. Application-based or Semantic Constraints
D. Foreign Key Constraints

C. Application-based or Semantic Constraints

What is an example of an Application-based or Semantic Constraint?
A. Each attribute should contain a single value
B. A department cannot have more than 10 employees
C. Values in a particular column or combination of columns must be unique
D. A list cannot be a value for any attribute

B. A department cannot have more than 10 employees

What are the three main types of explicit schema-based constraints in the relational model?
A. Primary key constraints, foreign key constraints, unique constraints
B. Domain integrity constraints, entity integrity constraints, referential integrity constraints
C. Check constraints, unique constraints, foreign key constraints
D. Entity integrity constraints, referential integrity constraints, primary key constraints

B. Domain integrity constraints, entity integrity constraints, referential integrity constraints

What do explicit schema-based constraints ensure in the relational model?
A. Conditions that must be present in valid relation states
B. Conditions that may or may not be present in valid relation states
C. Conditions that are optional in valid relation states
D. Conditions that are not relevant to valid relation states

A. Conditions that must be present in valid relation states

Which of the following is an example of explicit schema-based constraints?
A. A rule stating that a department cannot have more than 10 employees
B. A primary key constraint
C. A business-specific constraint enforced by an application program
D. A constraint based on the nature of the data model itself

B. A primary key constraint

What is the primary requirement of Domain Integrity constraints?
A. Every value in a tuple must be null.
B. Every value in a tuple must be from the domain of its attribute (or it could be null, if allowed for that attribute).
C. Every value in a tuple must be unique.
D. Every value in a tuple must be from a different domain.

B. Every value in a tuple must be from the domain of its attribute (or it could be null, if allowed for that attribute).

What does the "Not Null" constraint enforce?
A. Every value must be null.
B. Every value must be unique.
C. Every entry must include a value for a specified attribute.
D. Every entry must remain within a permissible range.

C. Every entry must include a value for a specified attribute.

What does the "Check" constraint ensure?
A. Every salary entered remains within the specified permissible range.
B. Every value must be null.
C. Every value must be unique.
D. Every entry must include a value for a specified attribute.

A. Every salary entered remains within the specified permissible range.

What does the "Unique" constraint guarantee?
A. Every value must be null.
B. No two employees share the same Emirate ID number.
C. Every entry must remain within a permissible range.
D. Every value must be from a different domain.

B. No two employees share the same Emirate ID number.

What does the Entity Integrity constraint dictate regarding primary key attributes?
A. Primary key attributes must contain null values in any tuple.
B. Primary key attributes must contain unique values in any tuple.
C. Primary key attributes must contain values from a different domain.
D. Primary key attributes cannot contain null values in any tuple.

D. Primary key attributes cannot contain null values in any tuple.

Why is the absence of null values in primary key attributes essential according to the Entity Integrity constraint?
A. To allow for variability in the primary key attributes.
B. To maintain the uniqueness and identification of each record.
C. To enable the use of composite primary keys.
D. To permit null values in other attributes.

B. To maintain the uniqueness and identification of each record.

How does the Entity Integrity constraint apply to composite primary keys?
A. Null values are allowed in any of the composite key attributes.
B. Null values are allowed in all composite key attributes.
C. Null values are disallowed in any of the composite key attributes.
D. Null values are required in all composite key attributes.

C. Null values are disallowed in any of the composite key attributes.

What is the impact of the Entity Integrity constraint on attributes other than the primary key?
A. Null values are not allowed in any attributes.
B. Null values are allowed in all attributes.
C. Null values are disallowed in all attributes.
D. Null values are allowed in attributes not part of the primary key.

D. Null values are allowed in attributes not part of the primary key.

What does the Referential Integrity constraint govern in a relational database?
A. The uniqueness of primary keys
B. The relationships between tables
C. The presence of null values in foreign keys
D. The absence of null values in foreign keys

B. The relationships between tables

In a referencing relation 𝑅1, what can the value in the foreign key column (FK) be?
A. A value that matches an existing foreign key value in the corresponding primary key PK of the referenced relation 𝑅2.
B. A value that matches an existing primary or unique key value in the corresponding primary key PK of the referenced relation 𝑅2.
C. A value that matches an existing primary key value in the corresponding primary key PK of the referenced relation 𝑅2.
D. A value that matches an existing primary key value in the corresponding unique key of the referenced relation 𝑅2.

B. A value that matches an existing primary or unique key value in the corresponding primary key PK of the referenced relation 𝑅2.

When does a foreign key (FK) value signify the existence of a relationship in the Referential Integrity constraint?
A. When the foreign key (FK) is NULL
B. When the foreign key (FK) is not NULL
C. When the foreign key (FK) matches an existing primary key value in the referenced relation
D. When the foreign key (FK) does not match an existing primary key value in the referenced relation

B. When the foreign key (FK) is not NULL

What does a NULL value in the foreign key (FK) indicate in the Referential Integrity constraint?
A. There is no relationship with the referenced relation.
B. There is a relationship with the referenced relation.
C. The foreign key value matches an existing primary or unique key value.
D. The foreign key value does not match an existing primary or unique key value.

A. There is no relationship with the referenced relation.

Can a foreign key reference a non-primary attribute in the referenced relation in the Referential Integrity constraint?
A. Yes, but only if the referenced attribute has a NULL constraint.
B. No, a foreign key can only reference primary attributes.
C. Yes, as long as the referenced attribute has a UNIQUE constraint.
D. No, foreign keys can only reference primary keys.

C. Yes, as long as the referenced attribute has a UNIQUE constraint.

What are possible violations during INSERT operations in a database?
A. Violations of Domain Integrity, Referential Integrity, and Entity Integrity
B. Violations of Entity Integrity only
C. Violations of Referential Integrity only
D. Violations of Domain Integrity only

A. Violations of Domain Integrity, Referential Integrity, and Entity Integrity

What is a possible violation during DELETE operations in a database?
A. Violation of Domain Integrity
B. Violation of Referential Integrity
C. Violation of Entity Integrity
D. Violation of Unique Constraints

B. Violation of Referential Integrity

What are the possible remedies for violations during DELETE operations?
A. Reject the deletion, Delete tuples referencing the deleted tuple, Set foreign keys of referencing tuples to NULL
B. Reject the deletion only
C. Delete tuples referencing the deleted tuple only
D. Set foreign keys of referencing tuples to NULL only

A. Reject the deletion, Delete tuples referencing the deleted tuple, Set foreign keys of referencing tuples to NULL

What are possible violations during UPDATE operations in a database?
A. Violations of Domain Integrity, Referential Integrity, and Entity Integrity
B. Violations of Entity Integrity only
C. Violations of Referential Integrity only
D. Violations of Domain Integrity only

A. Violations of Domain Integrity, Referential Integrity, and Entity Integrity

What can updating the primary key (PK) during an UPDATE operation potentially violate?
A. Domain Integrity
B. Referential Integrity
C. Entity Integrity
D. Unique Constraints

C. Entity Integrity

What can updating a foreign key (FK) during an UPDATE operation potentially violate?
A. Domain Integrity
B. Referential Integrity
C. Entity Integrity
D. Unique Constraints

B. Referential Integrity

What can updating an ordinary attribute (neither PK nor FK) during an UPDATE operation potentially violate?
A. Domain Integrity only
B. Referential Integrity only
C. Entity Integrity only
D. Unique Constraints only

A. Domain Integrity only