Question 1

In order to embed SQL inside of another language, the ________ statement must be placed before the SQL in the host language.

Accepted Answer

The EXEC SQL statement is used to embed SQL inside of another programming language, and must be used before the actual SQL code.

Question 2

User-defined transactions can improve system performance because:

Accepted Answer

User-defined transactions group multiple SQL statements into a single transaction, which reduces the overhead that comes with processing each individual SQL statement separately. As a result, grouping transactions into sets can improve system performance. The other choices are not relevant or accurate.

Question 3

The following code would include: 
SELECT Customer_T.CustomerID, Order_T.CustomerID,
CustomerName, OrderID
FROM Customer_T, Order_T
WHERE Customer_T.CustomerID = Order_T. CustomerID;

Accepted Answer

The code is using a JOIN statement to only select rows that match in both the Customer_T and Order_T tables based on the CustomerID column. It is not selecting all rows from either table, nor is it excluding any rows.

Question 4

Embedded SQL consists of:

Accepted Answer

Embedded SQL refers to hard-coded SQL statements that are included in programs written in another language, such as COBOL or C++. The SQL statements are typically embedded within the code using special programming constructs provided by the programming language.

Question 5

The following code would include: 
SELECT Customer_T.CustomerID,CustomerName, OrderID
FROM Customer_T LEFT OUTER JOIN Order_T ON
Customer_T.CustomerID = Order_T.CustomerID;

Accepted Answer

The LEFT OUTER JOIN operation returns all rows from the left table (Customer_T in this case) and only the matching rows from the right table (Order_T). However, because of the use of the LEFT OUTER JOIN, if there are no matching rows in the right table for a given row in the left table, the result set will still include that row from the left table, with NULL values in the columns from the right table. Therefore, this query will include all rows from the Customer_T table, regardless of whether there is a matching row in the Order_T table.

Question 6

An interactive command that can be used to dynamically control a user session for appropriate integrity measures is:

Accepted Answer

The correct choice is set autocommit. This command is used to dynamically control a user session to ensure appropriate integrity measures by either committing or rolling back transactions after they are executed. This helps maintain data consistency and prevent unintended changes to the database. Rollback and rollforward are commonly used in database management systems but are not interactive commands that can be used to dynamically control user sessions. Expunge is not a relevant command in this context.

Question 7

A join that is based upon equality between values in two common columns with the same name and where one duplicate column has been removed is called a(n):

Accepted Answer

This is exactly how a natural join is defined - it joins tables based on the equality of values in two common columns with the same name, and automatically removes one of the duplicate columns. Equi-join is a more general term that refers to any join based on equality between values in two columns, and does not necessarily involve duplicate columns or same-column names. Multivariate join is not a commonly used term. Inner join is a general term that refers to any join that includes only rows where there is a match in both tables being joined, and therefore does not specifically refer to the removal of duplicate columns.

Question 8

A join operation:

Accepted Answer

Join operation is used to combine tables with common domain. It allows to merge related data from two or more tables into a single table or view. Option A refers to selecting specific columns, Option C refers to merging unrelated data and Option D is not a valid definition of a join operation.

Question 9

In order for two queries to be UNION-compatible, they must:

Accepted Answer

For two queries to be UNION-compatible, they must have the same number of columns selected in their SQL statements, and the data types of those columns must be compatible, and both queries must return the same number of rows. They do not have to return exactly one row or have a minimum of one row returned.

Question 10

The following code is an example of a(n): SELECT Customer_T.CustomerID, Order_T.CustomerID,
CustomerName, OrderID
FROM Customer_T, Order_T
WHERE Customer_T.CustomerID = Order_T. CustomerID;

Accepted Answer

The code is performing an equi-join by matching the CustomerID column in the Customer_T and Order_T tables.

Question 11

The most commonly used form of join operation is the:

Accepted Answer

The answer of The most commonly used form of join...

Question 12

Establishing IF-THEN-ELSE logical processing within an SQL statement can be accomplished by:

Accepted Answer

The CASE keyword in SQL allows for conditional logic to be applied within a statement, similar to the if-then-else construct. It provides a way to evaluate a series of conditions and return a result based on the first condition that is true. Therefore, using the CASE keyword is the best choice to establish IF-THEN-ELSE logical processing within an SQL statement.

Question 13

All of the following are guidelines for better query design EXCEPT:

Accepted Answer

Using a lot of self-joins can often slow down the query processing time and may not be necessary for achieving the desired result. The other three options are all important guidelines for better query design. Understanding how indexes are used can help optimize the query, writing simple queries can improve readability and maintainability, and retrieving only the needed data can reduce the amount of data that needs to be processed and transferred.

Question 14

A ________ is a temporary table used in the FROM clause of an SQL query.

Accepted Answer

A derived table is a temporary table that is created and used in the FROM clause of an SQL query. It is derived from a query expression and is used as a subquery within the main query. The other options (correlated subquery, view table, and trigger) are not temporary tables used in the FROM clause of an SQL query.

Question 15

Explicit commands to manage transactions are needed when:

Accepted Answer

Explicit commands to manage transactions are needed when multiple SQL commands must be run as part of a transaction. This ensures that all the commands are treated as a single transaction and either all of them will be committed or rolled back if there are any errors.

Option A is incorrect because if a transaction consists of just one SQL command, there is no need to manage the transaction explicitly.

Option C is partially correct as autocommit being set to off may need explicit transaction management, but it is not the only condition where explicit commands are required.

Option D is not correct because the prohibition of DDL statements does not necessarily mean that explicit commands are needed for transaction management.

Question 16

The UNION clause is used to:

Accepted Answer

The UNION clause is used to combine the output from multiple queries into a single result table. It does not join tables or find unmatched rows.

Question 17

The ________ operator is used to combine the output from multiple queries into a single result table.

Accepted Answer

The UNION operator is used to combine the output from multiple queries into a single result table by appending the rows from one query to another. It only includes distinct rows, so duplicates are removed. The INTERSECT operator returns only the common rows between multiple queries. The DIVIDE operator is not a standard SQL operator, and the COLLATE operator is used to specify a collation sequence for a column or expression.

Question 18

A join in which the joining condition is based on equality between values in the common columns is called a(n):

Accepted Answer

An equi-join is a join condition based on equality between values in the common columns, whereas a natural join is a join based on all common columns between the two tables. Since an equi-join is a type of natural join, the correct answer is both A and C.

Question 19

Dynamic SQL:

Accepted Answer

Dynamic SQL allows for flexibility in generating SQL code based on changing conditions or requirements during application processing. It enables applications to create queries that are tailored to specific data and user requirements, making them more customized and efficient. It is commonly used in web applications and business intelligence systems. While it can be more volatile than static SQL, when used properly, it can enhance application performance and scalability.

Question 20

The following code would include: 
SELECT Customer_T.CustomerID,CustomerName, OrderID
FROM Customer_T RIGHT OUTER JOIN Order_T ON
Customer_T.CustomerID = Order_T.CustomerID;

Accepted Answer

The answer of The following code would include: 
SELECT Customer_T.CustomerID,CustomerName,...

Quiz 7: Advanced SQL