Question 1

A data field in a traditional file is similar to a relational:
A)table
B)attribute
C)tuple
D)row

Accepted Answer

A data field in a traditional file refers to a single piece of information stored in a record. Similarly, in a relational database, an attribute forms a column in a table and represents a characteristic or property of an entity. Therefore, choice B is the best fit. A table (choice A) consists of multiple rows and columns, and a tuple (choice C) refers to a single row in a table. A row (choice D) represents a complete record or instance of an entity in a table.

Question 2

An entity can be classified as all of the following except
A)resource
B)event
C)tuple
D)agent

Accepted Answer

All of the other options (resource, event, and agent) are examples of entities, but tuple is a term used to describe a collection of related values or attributes. It is not typically considered an entity in and of itself.

Question 3

SQL is a powerful database language that can be used to define database systems, query the database for information, generate reports from the database, and access databases from within programs using embedded commands.

Accepted Answer

SQL stands for Structured Query Language and is a widely used database language that can perform various operations on databases. It is known for its ability to define database structures, retrieve data from databases, generate reports, and interact with databases through embedded commands in programs.

Question 4

Queries of a database are driven by SELECT commands.

Accepted Answer

SELECT commands are used to retrieve data from a database through queries.

Question 5

A relation in an ER model is the same as an entity in the REA model.

Accepted Answer

In the ER model, a relation represents a connection or association between entities, while in the REA model, entities represent resources, events, and agents. Therefore, a relation in ER model is not the same as an entity in REA model.

Question 6

A(n) ____ of an entity is on specific thing of the type defined by the entity.
A)agent
B)composite attribute
C)attribute
D)instance

Accepted Answer

An instance of an entity is a specific occurrence or occurrence of the defined entity. It refers to a unique object or individual that belongs to a certain class. For example, "John Smith" can be an instance of the "Customer" entity in a database system.

Question 7

Which of the following is an attribute but least likely to be the key attribute?
A)client
B)client number
C)client name
D)client street address

Accepted Answer

Client street address is an attribute that describes a client but is not unique to each client, meaning it is least likely to be the key attribute. Client number and client name are more likely to be key attributes because they are generally unique to each client.

Question 8

Which of the following is a composite attribute?
A)client
B)client number
C)client name
D)client street address

Accepted Answer

A composite attribute is an attribute that can be divided into smaller sub-parts. Client street address can be divided into sub-parts such as street name, city, state, and zip code, making it a composite attribute. Client, client number, and client name are not composite attributes as they cannot be divided into smaller sub-parts.

Question 9

The INSERT command is used to add a single tuple to an existing relation.

Accepted Answer

The INSERT command is used to add a single tuple to an existing relation.

Question 10

Which of the following is the entity or agent?
A)client
B)client number
C)client name
D)client street address

Accepted Answer

An entity or agent is typically a person, organization, or system that can perform actions or have actions performed on it. In this context, "client" represents the entity, while the other options are attributes or properties of the client.

Question 11

Relational integrity specifies that for every attribute in one relation that has been specified to allow reference to another relation, the tuple being referenced must remain intact.

Accepted Answer

The answer of Relational integrity specifies that for every attribute...

Question 12

A key attribute is the attribute whose value is:
A)undeterminable
B)unique
C)large
D)the same for all attributes

Accepted Answer

A key attribute is a unique identifier for each instance of an entity. No two instances of an entity can have the same value for a key attribute.

Question 13

A(n) ____ is an item of data that characterizes an entity or relationship
A)agent
B)composite attribute
C)attribute
D)instance

Accepted Answer

Attributes are characteristics or properties of entities or relationships such as name, age, address, etc. They describe the entity's various properties.

Question 14

The DELETE command is used when we want to change one or more attribute values.

Accepted Answer

The DELETE command is used to remove an entire row or record from a database table. To change attribute values, the UPDATE command is used.

Question 15

Most DBMS available today that include SQL also include mechanisms within the DBMS itself for establishing and enforcing referential integrity.

Accepted Answer

Most modern DBMS include mechanisms for establishing and enforcing referential integrity within the DBMS itself. SQL itself also includes features for defining and enforcing referential integrity constraints.

Question 16

A missing value is called a non-null.

Accepted Answer

A missing value is called a null value. A non-null value means that there is a value present in the data.

Question 17

Which of the following is the key attribute?
A)client
B)client number
C)client name
D)client street address

Accepted Answer

The key attribute is a unique identifier for each client. While all of the options provided could potentially be useful pieces of information for a client, only the client number is guaranteed to be unique and able to accurately identify a specific client within a database.

Question 18

The secondary key is specified to uniquely identity each tuple in the relation.

Accepted Answer

The primary key is specified to uniquely identify each tuple in the relation. A secondary key is any key that is not the primary key but still allows for unique identification of each tuple.

Question 19

For the following entity and attribute model, what would be the key attribute of the Students entity? 
A)social security number
B)name
C)address
D)street

Accepted Answer

The social security number is a unique identifier for each individual student and therefore the best choice for the key attribute of the Students entity. Name, address, and street are not guaranteed to be unique identifiers and could potentially lead to data duplication or errors.

Question 20

The UPDATE command demonstrates one of the weaknesses in most forms of SQL.

Accepted Answer

The UPDATE command is a standard SQL operation used to modify existing data in a database. It does not inherently demonstrate a weakness in SQL; rather, it is a fundamental feature for data manipulation. SQL weaknesses typically relate to security, efficiency, or complexity in handling certain types of data or operations, not to basic commands like UPDATE.

Quiz 6: Relational Databases and Sql

A data field in a traditional file is similar to a relational:

An entity can be classified as all of the following except

SQL is a powerful database language that can be used to define database systems, query the database for information, generate reports from the database, and access databases from within programs using embedded commands.

Queries of a database are driven by SELECT commands.

A relation in an ER model is the same as an entity in the REA model.

A(n) ____ of an entity is on specific thing of the type defined by the entity.

Which of the following is an attribute but least likely to be the key attribute?

Which of the following is a composite attribute?

The INSERT command is used to add a single tuple to an existing relation.

Which of the following is the entity or agent?

Relational integrity specifies that for every attribute in one relation that has been specified to allow reference to another relation, the tuple being referenced must remain intact.

A key attribute is the attribute whose value is:

A(n) ____ is an item of data that characterizes an entity or relationship

The DELETE command is used when we want to change one or more attribute values.

Most DBMS available today that include SQL also include mechanisms within the DBMS itself for establishing and enforcing referential integrity.

A missing value is called a non-null.

Which of the following is the key attribute?

The secondary key is specified to uniquely identity each tuple in the relation.

For the following entity and attribute model, what would be the key attribute of the Students entity?

The UPDATE command demonstrates one of the weaknesses in most forms of SQL.