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

In Oracle, *_TABLES views provide information about tables.

B. USER_TABLES displays all tables owned by the current user, making this statement true. No additional privileges are required to see your own tables.

D. ALL_TABLES displays all tables that the current user has access to, either through direct ownership or through privileges, making this statement true.

A, C, E, and F are incorrect. Specifically:

A and E are incorrect because you do not need ANY TABLE system privileges to view tables in DBA_TABLES or ALL_TABLES; you need the SELECT_CATALOG_ROLE or equivalent privileges.

C is incorrect because as a user, you do not need additional privileges to see your own tables in USER_TABLES.

F is incorrect because not all users can query DBA_TABLES; this requires specific privileges or roles.

References:

Oracle Database Reference, 12c Release 1 (12.1): "Static Data Dictionary Views"

Regarding creating tables in an Oracle database:

B. The same table name can be used for tables in different schemas: In Oracle, a schema is essentially a namespace within the database; thus, the same table name can exist in different schemas without conflict, as each schema is distinct.

C. A system privilege is required: To create tables, a user must have the necessary system privileges, typically granted explicitly or through roles such as CREATE TABLE or administrative privileges depending on the environment setup.

Incorrect options for all three repeated questions:

A: Oracle SQL does not allow specifying the maximum number of rows directly in a CREATE TABLE statement; this is controlled by storage allocation and database design rather than table creation syntax.

D: Creating an external table does not create the physical file. It merely creates a table structure that allows access to data stored in an external file specified in the directory; the file itself must already exist or be managed outside of Oracle.

E: A primary key constraint is not mandatory for creating tables. While it is a common practice to define a primary key to enforce entity integrity, it is not required by the Oracle SQL syntax for table creation.

These answers and explanations are aligned with Oracle Database 12c SQL documentation and standard practices.

Given the statements, the failure to execute would be due to improper SQL syntax or logical structuring of the JOIN clause:

A. SELECT * FROM employees e JOIN department d WHERE e.department_id=d.department_id AND d.department_id=90: This statement will fail because it incorrectly uses the JOIN syntax without an ON clause, which is necessary to specify the condition on which the tables are joined. This statement mistakenly places the join condition in the WHERE clause without using ON.

Correct options (executes successfully):

B: Correctly formulated JOIN with ON and an additional condition in the WHERE clause.

C: Incorporates the filtering directly in the ON clause, which is a valid method to restrict the rows returned by the JOIN based on conditions related to both tables.

D: Although it appears awkward due to the order of conditions in the ON clause, it is syntactically correct.

These answers reflect typical use and constraints in SQL queries and are aligned with Oracle Database 12c standards for SQL syntax and operations.

The queries that will return all the rows from the COLORS table are those that ensure every record from COLORS is selected, regardless of whether there's a matching record in the BRICKS table:

Option A:

SELECT * FROM bricks b RIGHT JOIN colors c ON b.color_rgb_hex_value = c.rgb_hex_value;

A right join will return all the rows from the right table (COLORS), with the matching rows from the left table (BRICKS). If there is no match, NULL will be returned for columns from BRICKS.

Option B:

SELECT * FROM colors c LEFT JOIN bricks b USING (rgb_hex_value);

A left join will return all the rows from the left table (COLORS), with the matching rows from the right table (BRICKS). If there is no match, NULL will be returned for columns from BRICKS. The USING clause indicates a join condition where columns with the same names are compared for equality.

Options C, D, and E will not return all the rows from the COLORS table:

Option C: The full join will return all rows from both tables, but it is not restricted to only the rows from COLORS.

Option D: An inner join will return only the matching rows between both tables, not all rows from COLORS.

Option E: This is a left join, which would typically return all rows from COLORS, but the WHERE clause restricts the result set to only those rows from COLORS that have a matching BRICK_ID in BRICKS which is greater than 0, potentially excluding rows from COLORS.