Oracle 1z0-071 Exam Made Easy: Step-by-Step Preparation Guide

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.

Oracle synonyms are used to simplify the referencing of complex schema objects:

Option A: Incorrect. A synonym cannot have another synonym; it directly references the base object.

Option B: Incorrect. A synonym does not have an object number as it is merely an alias for another object.

Option C: Correct. Any user with sufficient privileges can create a public synonym, which is accessible to all users in the database.

Option D: Incorrect. All private synonym names must be unique within a schema but not across the entire database.

Option E: Correct. Synonyms can be created for objects within packages, such as procedures or functions, simplifying the referencing of these objects without needing to specify the full package name.

A: True. The WITH GRANT OPTION allows the grantee to grant the object privileges they received to another user or role. This can be used for both system and object privileges, thereby extending the privilege chain.

D: True. When an object privilege granted with the WITH GRANT OPTION is revoked, it also revokes the privileges that the grantee had re-granted to others. This is referred to as a cascading effect, which can impact multiple users and roles depending on the extent of re-granting.

F: True. To add a foreign key constraint that references a table in another schema, the user must have the REFERENCES object privilege on the target table in the other schema. This privilege is specific and necessary for the integrity constraints involving foreign keys.

In Oracle SQL, the q quote operator can be used to define string literals that contain single quotes or other special characters without needing to escape them. The queries using the q quote mechanism, like in options A and C, will successfully return the string as it is, including single quotes within the string.

A: Correct, it uses the q quote operator with the exclamation mark ! as the delimiter, which allows the string to contain single quotes.

B: Incorrect, double quotes " in Oracle SQL are used for identifiers such as column names, not string literals.

C: Correct, this also uses the q quote operator, with the square brackets [] as the delimiters.

D: Incorrect, the backslash \ is not used as an escape character in Oracle SQL string literals, and the ESCAPE keyword is used incorrectly here.

E: Incorrect, this does not account for the single quote within the string, which would terminate the string literal prematurely, and it lacks the q quote operator or proper escape mechanism.

An index is created automatically on columns that are defined with a UNIQUE constraint and a PRIMARY KEY constraint.

A. True. Since the serial_no column is defined with a UNIQUE constraint, Oracle will automatically create an index for this column.

E. True. The order_id column is defined with a PRIMARY KEY constraint, and Oracle automatically creates a unique index on the primary key column.

A: This statement will not execute successfully because you cannot subtract a DAY interval from a DATE directly. SYSDATE needs to be cast to a TIMESTAMP first.

B: This statement is correct. It adds an interval of '1' DAY to the current TIMESTAMP.

C: This statement is correct. It subtracts an interval of '1' MINUTE from '1' DAY.

D: This statement will not execute successfully. In Oracle, you cannot add intervals of different date fields (DAY and MONTH) directly.

E: This statement has a syntax error with the quotes around INTERVAL and a misspelling, it should be 'INTERVAL'.

Oracle Database 12c SQL supports interval arithmetic as described in the SQL Language Reference documentation.

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.

B. SELECT product_id, (unit_price * 0.15 / (4.75 + 552.25)) FROM products; C. SELECT product_id, (expiry_date - delivery_date) * 2 FROM products; E. SELECT product_id, unit_price, unit_price + surcharge FROM products;

Comprehensive and Detailed Explanation WITH all References:

A. This is invalid because "Discount" is a string literal and cannot be used without quotes in an arithmetic operation. Also, there is a typo in unit_pricer, and 'discount' is not a defined column in the table. B. This is valid. It shows a mathematical calculation with unit_price, which is of NUMBER type. Division and multiplication are valid operations on numbers. C. This is valid. The difference between two DATE values results in the number of days between them, and multiplying this value by a number is a valid operation. D. This is invalid because expiry_date is of DATE type and cannot be multiplied by a number. Also, there's a typo: "SPLECT" should be "SELECT". E. This is valid. Both unit_price and surcharge are NUMBER types, and adding them together is a valid operation. F. This is invalid because concatenation operator || is used between a number (unit_price) and a string literal "Discount", which is not enclosed in single quotes, and 'discount' is not a defined column in the table.

In SQL, arithmetic operations on numbers and date arithmetic are valid expressions. Concatenation is also a valid expression when used correctly between string values or literals. Operations that involve date types should not include multiplication or division by numbers directly without a proper interval type in Oracle SQL.

These rules are detailed in the Oracle Database SQL Language Reference, where expressions, datatype precedence, and operations are defined.

When using the GROUP BY clause, every column in the SELECT clause that is not an aggregate function must be included in the GROUP BY clause:

A. SELECT dept_id, join_date, SUM(salary) FROM employees GROUP BY dept_id, join_date: This is a valid query because all non-aggregate columns in the SELECT list (dept_id and join_date) are included in the GROUP BY clause.

Queries B and C are invalid because they attempt to nest aggregate functions, which is not allowed. Query D is invalid because join_date is not included in the GROUP BY clause.

References:

Oracle Database SQL Language Reference 12c, specifically the section on GROUP BY clause constraints.

The LIKE operator is used in SQL to search for a specified pattern in a column. To find all customers residing in cities starting with 'D' followed by at least two characters, you need to use the LIKE operator with the appropriate wildcard pattern:

A. SELECT * FROM customers WHERE city LIKE 'D_%'; The underscore () wildcard character in SQL represents a single character. The percent (%) wildcard character represents zero or more characters. So 'D%' will match any city starting with 'D' followed by at least one character (as there is one underscore).

References:

Oracle Database SQL Language Reference 12c, specifically the section on pattern matching with the LIKE condition.