Oracle Updated 1z0-071 Exam Questions and Answers by maisy

A. A customer can exist in many countries. This is true as customers can have multiple addresses or operations in different countries, and a database design can reflect this by allowing multiple country entries for a single customer1.

C. The statement will fail because subquery may not be I contained in a values clause. In Oracle Database 12c, a subquery cannot be used within the VALUES clause of an INSERT statement. The correct approach would be to use the subquery in conjunction with the INSERT INTO … SELECT syntax if multiple rows are derived from a subquery2.

F. A product can have a different unit price at different times. It is common for products to have different unit prices at different times due to various factors such as promotions, discounts, or changes in cost price. This can be represented in a database by having a price history table or a similar mechanism to track the changes in price over time1.

Note: The other options are incorrect because:

B. The statement about the SALES table failing if a row already exists for product 23 is not necessarily true. Oracle allows for multiple rows with the same product ID if the table is designed to handle such cases, like having a composite primary key or no constraints preventing duplicates.

D. Without specific information about the SALES table’s design, we cannot verify the number of foreign keys it has.

E. The statement about the successful execution and insertion of a new row into the SALES table is too vague without the context of the actual SQL statement being referred to.

The ORDER BY clause is used in a SELECT statement to sort the returned rows by one or more columns.

A. This clause would attempt to order by ename as if it were a numeric column, which is not correct since ename is not numeric.

B. This is the correct answer. The NVL function replaces nulls with the specified value, in this case, 0. This clause sorts by comm, with nulls considered as 0 and appearing first, followed by the actual values, and then sorts by ename.

C. This clause is incorrect because it would place null values at the end, but in the output, rows with null comm appear at the beginning.

D. This clause would sort the comm in descending order with the nulls at the end, which is not consistent with the output shown.

References:

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "ORDER BY Clause"

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "NVL Function"

Please note that the correct formatting of SQL statements and clauses is crucial for the successful execution of queries.

To retrieve the names of the three employees with the lowest salaries, the correct SQL syntax and logic are crucial:

Option B:

SELECT last_name, salary FROM employees ORDER BY salary FETCH FIRST 3 ROWS ONLY;

This query correctly sorts employees by their salary in ascending order and fetches the first three rows only. The FETCH FIRST n ROWS ONLY syntax is a standard way to limit the result set in SQL.

Options A, C, D, and E do not correctly implement the logic for fetching the lowest three salaries due to misuse of ROWNUM or incorrect placement of ORDER BY and FETCH clauses.

The || operator is used in Oracle SQL to concatenate strings, and the q quote operator allows you to use alternative quoting mechanisms to avoid conflicts with single quotes within a string.

In options A, B, C, D, E, and F, the q-quote operator is used in different ways to define string literals.

The correct use of the q quote operator requires the format q'[...]', where [...] is the quote delimiter of your choice and can be any single character such as {, [, (, <, or others.

Option D is the correct answer because it follows the correct syntax for the q quote operator and concatenates the literal string correctly with the value of PROD_ID.

Here is the corrected syntax from option D:

SELECT PROD_ID || q'[('s not available)]' "CURRENT AVAILABILITY" FROM product_status WHERE status = 'OUT OF STOCK';

This query will execute successfully and is the only one that correctly uses the q quote operator.