Question 1

Which command creates a table containing all rows that are in either or both of two tables?

Accepted Answer

The command that creates a table containing all rows that are in either or both of two tables is UNION. UNION combines the results of two SELECT statements into a single table that includes all the rows that are in either or both of the tables.

Question 2

Which operation is performed by the SUBTRACT command in relational algebra?

Accepted Answer

The SUBTRACT command in relational algebra is equivalent to the set difference operation, which retrieves all tuples from one relation that are not in another relation. Therefore, the correct choice is B, difference.

Question 3

The relationships between tables are implemented through common ____________________.

Accepted Answer

The answer of The relationships between tables are implemented through...

Question 4

Which command contains all rows that are common in two tables?

Accepted Answer

The INTERSECT command contains all rows that are common in two tables.

Question 5

The compound criteria (conditions) are created by using which of the following two keywords?

Accepted Answer

The keywords used to create compound criteria (conditions) are AND and OR. Option A includes the correct keywords, while the other options include incorrect keywords or incorrect combinations of keywords.

Question 6

A(n) ____________________ database is a collection of tables.

Accepted Answer

The answer of A(n) ____________________ database is a collection of...

Question 7

Based on the table below, which command creates a new table named CustState containing the fields CustomerNum and State??Customer (CustomerNum, CustomerName, Street, City, State, PostalCode)

Accepted Answer

The correct command to create a new table named CustState containing only the fields CustomerNum and State from the Customer table is to use the PROJECT operation. This operation selects specific columns from an existing table to create a new table.

Question 8

Which operation will allow you to extract data from more than one table?

Accepted Answer

The join operation allows you to extract data from more than one table by combining them based on a common attribute or column. This is useful when you need to retrieve data that is related across multiple tables in a database. The other options (select, project, and merge) only allow you to work with data from a single table at a time.

Question 9

Based on the tables below, which command creates a new table named CustSales that combines the Customer and SalesPerson tables based on SalesPersonNum??Customer (CustomerNum, CustomerName, Street, City, State, PostalCode, SalesPersonNum)?SalesPerson (SalesPersonNum, LastName, FirstName)

Accepted Answer

The correct command to create a new table named CustSales that combines the Customer and SalesPerson tables based on SalesPersonNum is the JOIN command. The WHERE clause should specify the condition for the join, which is Customer.SalesPersonNum=SalesPerson.SalesPersonNum. The resulting table should be named CustSales using the GIVING keyword. Therefore, the correct command is JOIN Customer SalesPerson WHERE Customer.SalesPersonNum=SalesPerson.SalesPersonNum GIVING CustSales.

Question 10

Multiple entries in tables are often called ____________________.

Accepted Answer

The answer of Multiple entries in tables are often called...

Question 11

When some of the entries in a structure contain repeating groups and thus are not single-valued, the structure is called a(n) ____________________.

Accepted Answer

The answer of When some of the entries in a...

Question 12

Which of the following is true if two tables have the same number of columns and their corresponding columns represent the same type of data?

Accepted Answer

If two tables have the same number of columns and their corresponding columns represent the same type of data, they are union compatible. This means that the tables can be combined using a UNION operation to create a new table with all the rows from both tables.

Question 13

In relational algebra, what command causes only certain columns to be included in the new table?

Accepted Answer

The PROJECT command in relational algebra is used to project or select specific columns from a table and create a new table consisting of only those selected columns. Therefore, option D is the correct choice. SELECT is used to select specific rows based on certain conditions, DELETE is used to remove rows from a table and PROGRAM is not a valid command in relational algebra.

Question 14

Which operator is used to concatenate every row in the first table with every row in the second table?

Accepted Answer

The operator used to concatenate every row in the first table with every row in the second table is called the Cartesian product or cross join. Therefore, the best choice is C - product.

Question 15

What type of query changes data?

Accepted Answer

An update query changes data in a table.

Question 16

A ______________ primary key is composed of more than one column so that the row is unique.

Accepted Answer

The answer of A ______________ primary key is composed of...

Question 17

Based on the table below, which command lists all information from the table concerning the customer with CustomerNum 260? Customer (CustomerNum, CustomerName, Street, City, State, PostalCode)

Accepted Answer

The correct SQL syntax to retrieve all information for a specific row based on a condition (in this case, where CustomerNum equals 260) is represented by option B. The correct format is "SELECT * FROM table_name WHERE condition", but since the question's options don't follow standard SQL exactly, option B is the closest to the correct syntax, indicating a selection from the Customer table where CustomerNum equals 260.

Question 18

If you are sorting records by more than one field, which field is the more important field?

Accepted Answer

The primary sort key is the most important field for sorting records because it is the first field used to sort the records. The secondary sort key is used when records in the primary sort key have the same value, but it is not more important than the primary sort key. The maximum and minor sort keys are not commonly used terms in sorting records.

Question 19

What type of query creates a new table using the query results?

Accepted Answer

The make-table query creates a new table using the query results. A new table is created by specifying the name of the new table and the fields you want to include in the new table. This is useful for creating temporary tables or for creating tables from the results of a complex query.

Question 20

What type of functions are Count, Sum, Avg, Max, and Min?

Accepted Answer

Count, Sum, Avg, Max, and Min are all aggregate functions, which means they perform calculations on a set of values (usually a column in a database) and return a single value as the result. These functions are commonly used in SQL queries and data analysis.

Quiz 2: The Relational Model 1: Introduction, QBE, and Relational Algebra