Oracle PL 1z0-071 Release Date

• A: This statement is false. You cannot add a foreign key to a global temporary table because the data in a global temporary table is session-specific, while a foreign key constraint implies a permanent relationship.
• B: This statement is false. The ON COMMIT PRESERVE ROWS clause specifies that the data in the table should be preserved until the end of the session, not deleted at the end of the transaction.
• C: This statement is false. You can drop a global temporary table without truncating it first.
• D: This statement is true. You can alter a global temporary table to add columns within a session.
• E: This statement is false. Data in a global temporary table with the ON COMMIT PRESERVE ROWS clause is private to the session that inserted the data, and cannot be seen by other sessions.

In Oracle Database 12c, the INTERSECT operator is used in compound queries to return only the rows that are common to both SELECT statements involved in the query. Here's a breakdown of why the correct answer is C:

• A: Incorrect. The order of the tables in an INTERSECT operation does not affect the output because INTERSECT returns only the common elements between the two queries. The operation is symmetric.
• B: Incorrect. While the column names themselves can differ between the two SELECT statements, the data types and the number of columns must match for INTERSECT to function correctly.
• C: Correct. INTERSECT returns the intersection of the results of the two queries, which includes only rows that are found in both result sets.
• D: Incorrect. The number of columns and their data types in each SELECT statement of the INTERSECT must be the same to avoid errors and to correctly perform the comparison.
• E: Incorrect. INTERSECT does not ignore NULLs; rows with NULL values in corresponding columns must exactly match (both sides having NULLs in the same column) to be included in the output.