Oracle 1z0-071 Exam With Confidence Using Practice Dumps

For the SELECT statement from two tables without a JOIN clause:

Option B: You can add a WHERE clause with filtering criteria.

A WHERE clause can be added to a query to filter the results based on specified conditions.

Option E: It returns the same rows as SELECT * FROM bricks CROSS JOIN colors.

A comma-separated list of tables in a FROM clause is equivalent to a CROSS JOIN, resulting in a Cartesian product of the tables.

Options A, C, and D are incorrect because:

Option A: You cannot add an ON clause without changing the comma-separated FROM clause to a proper JOIN.

Option C: It returns the Cartesian product, not the sum, of the rows from BRICKS and COLORS.

Option D: A USING clause is not applicable without changing the syntax to a proper JOIN.

A. Correct. Foreign key constraints can be nullable. This allows the possibility of a row not having a link to another table. B. Incorrect. Unique key constraints do not allow multiple rows to have null values unless the constraint is defined on multiple columns. C. Incorrect. Primary key columns must be NOT NULL and unique across the table. D. Incorrect. Primary or unique key values do not refer to foreign keys; it's the foreign keys that refer to primary or unique keys. E. Correct. Foreign key constraints enforce referential integrity by requiring that each foreign key value matches a primary or unique key value in the related table.

These are standard rules in relational databases, which can be confirmed in the Oracle Database Concepts Guide.

A: 'CREATE SEQUENCE emp_seq START WITH 1 INCREMENT BY 1 NOCACHE;' is correct for ensuring unique values without gaps as much as possible by not caching sequence numbers, which might otherwise be lost in a system crash.

B: CYCLE allows the sequence to restart when its max/min value is reached, which does not help with requirement 3 (duplicates are never permitted). Therefore, B is incorrect.

C: This lacks the necessary attributes like START WITH and INCREMENT BY which are crucial to defining a sequence. Thus, statement C is incorrect.

D: 'CREATE SEQUENCE emp_seq START WITH 1 CACHE;' might introduce gaps due to the caching of sequence numbers. This statement is somewhat contrary to requirement 5.

E: 'CREATE SEQUENCE emp_seq START WITH 1 INCREMENT BY 1 CACHE;' will provide continuous unique values, but may include gaps when the cache is lost due to a restart, yet it is more efficient and still generally aligns with the requirements. Hence, statement E is considered correct.

F: This lacks detail and is too ambiguous, lacking the necessary parameters. Therefore, F is incorrect.