Pearson 1z0-071 New Attempt

When performing DML operations on a view without INSTEAD OF triggers:

Option C: Views cannot be used to add rows to an underlying table if the table has columns with NOT NULL constraints lacking default values which are not referenced in the defining query of the view.

This is true because the view would not provide values for NOT NULL columns without defaults, leading to an error.

Option D: Views cannot be used to add or modify rows in an underlying table if the defining query of the view contains the DISTINCT keyword.

Using DISTINCT in the view’s defining query can make the view non-updatable, as it may aggregate multiple rows into one.

Option E: Delete statements can always be done on a table through a view.

Deletes through a view are typically unrestricted as long as the view does not involve aggregates, DISTINCT, or similar constructs that would logically preclude determining which underlying rows should be deleted.

When using the TRUNCATE TABLE command in Oracle, several aspects of the table's structure and associated database objects are impacted. Here's an explanation of each option:

A: Incorrect. TRUNCATE TABLE does not drop triggers associated with the table; they remain defined.

B: Correct. Indexes on the table are retained and not dropped when you truncate a table. However, if the index is a domain index, it may be dropped depending on its type.

C: Correct. Integrity constraints such as primary keys, foreign keys, etc., are retained unless they are on a disabled state where truncation can lead to constraint being dropped.

D: Incorrect. A TRUNCATE TABLE operation cannot be rolled back. It is a DDL (Data Definition Language) operation and commits automatically.

E: Incorrect. The TRUNCATE TABLE operation deallocates the space used by the data unless the REUSE STORAGE clause is specified.

F: Incorrect. TRUNCATE TABLE operation removes all the rows in a table and does not log individual row deletions, thus FLASHBACK TABLE cannot be used to retrieve the data.

For the provided UNION ALL query:

Option C: It will return rows from both SELECT statements including duplicate rows.

UNION ALL is used to combine the results of two SELECT statements and does not eliminate duplicates.

Options A, B, and D are incorrect because:

Option A: UNION ALL does not eliminate duplicate rows, unlike UNION.

Option B: This would be true for INTERSECT, not UNION ALL.

Option D: This would be true for EXCEPT or MINUS, not UNION ALL.

To calculate the length of employment, you would compare the current date to the HIRE_DATE and calculate the difference in years.

A. This is the correct answer. The expression calculates the number of days between the current date (SYSDATE) and the HIRE_DATE, then divides by 365 to convert it to years, and checks if it is greater than 5.

B. SYSTIMESTAMP includes a time component including fractional seconds and time zone information, making this comparison incorrect.

C. There are typos in this option (CUARENT_DATE should be CURRENT_DATE and hire_data should be hire_date). Even with the correct function and column names, CURRENT_DATE returns the current date in the session time zone, not in years.

D. There are typos in this option (SYSNAYW should be SYSDATE). Additionally, dividing by 12 incorrectly assumes that a month is equivalent to a year.

E. This is a repetition of option D with the same issues.

F. There are typos in this option (CUNACV_DATE should be CURRENT_DATE and hire_data should be hire_date). Additionally, dividing by 12 incorrectly assumes that a month is equivalent to a year.

References:

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "Date Functions"