Pass the Oracle Oracle PL 1z0-071 Questions and answers with CertsForce

A. PRODUCT_ID can be assigned the PRIMARY KEY constraint.

In Oracle Database 12c, a PRIMARY KEY constraint is a combination of a NOT NULL constraint and a unique constraint. It ensures that the data contained in a column, or a group of columns, is unique among all the rows in the table and not null. Given the PRODUCT_ID is marked as NOT NULL, it is a candidate for being a primary key because we can assume that it is intended to uniquely identify each product in the table.

Queries that will execute successfully given the PRODUCT_STATUS table:

C. SELECT prod_id || q'('s not available)' "CURRENT AVAILABILITY" FROM product_status WHERE status = 'OUT OF STOCK';This query will execute successfully because it uses the q quote operator correctly to handle the inclusion of single quotes in the string.

D. SELECT prod_id || q'('s not available)' FROM product_status WHERE status = 'OUT OF STOCK';Similar to the previous query, it uses the q quote operator correctly and will execute without syntax errors.

Options A, B, E, and F are incorrect because of the incorrect or incomplete use of the quote operator:

A is incorrect because it has an additional single quote before the FROM clause.

B is incorrect because of a missing ending single quote after the q quote operator.

E and F are incorrect because they both use the q quote operator incorrectly; q’(’s not available)' is not a valid use of the quote operator, and q"'s not available" incorrectly uses double quotes instead of single quotes.

In Oracle SQL, when using the set operators like MINUS, the number of columns and their data types in the SELECT statements must match in sequence.

A. This query will not execute successfully because the SELECT * FROM bricks_stage will return all columns from the BRICKS_STAGE table, which are WEIGHT, SHAPE, and COLOR, but the first SELECT statement specifies only SHAPE and COLOR. The order and number of columns must match.

B. This query will not execute successfully. The SELECT statements have a different number of columns, and the data types of the columns in the same positions do not match between the two queries. The first column in the first SELECT is SHAPE (VARCHAR2), and in the second SELECT, it is WEIGHT (NUMBER).

C. This query will execute successfully. The SELECT * from both tables will ensure that the number of columns and their data types are the same, as SELECT * selects all columns from the table. As long as the two tables have the same column order and data types for those columns, the query will execute.

D. This query will not execute successfully. Even though the columns are of the same data types, their order in the SELECT statements must match for the set operator to work. The order of SHAPE and COLOR is switched between the two queries.

E. This query will not execute successfully. The number of columns in the SELECT statements is the same, but their data types do not match between the two queries. BRICK_ID (NUMBER) in the first query does not match WEIGHT (NUMBER) in the second, and SHAPE (VARCHAR2) does not match COLOR (VARCHAR2).

References:

Oracle Database SQL Language Reference, 12c Release 1 (12.1): "Combining Queries with Set Operators"

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

When the TRUNCATE TABLE command is used:

C. It retains the indexes defined on the table. This is true. The TRUNCATE TABLE operation does not drop the indexes on the table; it only removes all rows from the table.

D. It retains the integrity constraints defined on the table. This is correct. The TRUNCATE TABLE operation does not affect the integrity constraints; it retains them.

Options A, B, E, and F are incorrect:

A is incorrect because the TRUNCATE TABLE operation cannot be rolled back as it is a DDL operation and not a DML operation like DELETE.

B is incorrect because TRUNCATE TABLE does not drop any triggers; they remain in place.

E is incorrect as TRUNCATE TABLE may or may not release the space depending on whether the REUSE STORAGE clause is used.

F is incorrect because FLASHBACK TABLE cannot be used to retrieve data after a TRUNCATE TABLE operation since it does not generate redo logs that FLASHBACK relies upon.

A. This statement is incorrect because TO_NUMBER expects a character string as an argument, not a date. Directly converting a date to a number without an intermediate conversion to a character string would result in an error. B. This statement is incorrect. Multiplying a date by a number does not make sense in SQL, and attempting to convert such an expression to a date will also result in an error. C. This statement is correct. Subtracting two dates in Oracle SQL results in the number of days between those dates, hence the result is a number. D. This statement is correct. Subtracting a number from a date in Oracle SQL will subtract that number of days from the date, returning another date. E. This statement is incorrect. As stated in C, subtracting a date from SYSDATE correctly returns the number of days between those two dates, not an error.

These concepts are explained in the Oracle Database SQL Language Reference, which details date arithmetic in SQL.

For question 134, the correct options are B and F based on the capabilities and design of SQL:

B. It best supports relational databases: SQL is fundamentally designed to manage and query data in relational databases. It is the standard language used for managing relational database management systems (RDBMS) and for performing all types of data operations within them.

F. It provides independence for logical data structures being manipulated from the underlying physical data storage: SQL allows users to interact with the data at a logical level without needing to know how the data is physically stored. This is known as logical data independence, which is a key feature of SQL in managing databases.

Other options are incorrect because:

A: SQL itself doesn't guarantee ACID properties; these are provided by the database management system's transaction control mechanisms.

C, D, E: These statements are incorrect as SQL does not inherently support object-oriented concepts like encapsulation and polymorphism, is not limited to hierarchical data storage, and is not the only language used for both relational and object-oriented databases.

Scalar subquery expressions are used in Oracle SQL to return a single value from a subquery.

Option C: They can be nested.

Scalar subqueries can indeed be nested within another scalar subquery, provided each subquery returns a single value.

Option D: A scalar subquery expression that returns zero rows evaluates to null.

According to Oracle documentation, if a scalar subquery returns no rows, the result is a NULL value, not zero or any other default.

Option F: They can be used as default values for columns in a create table statement.

Scalar subqueries can be specified in the DEFAULT clause of a column in a CREATE TABLE statement to dynamically assign default values based on the result of the subquery.

Options A, B, and E are incorrect based on Oracle SQL standards and functionalities.