Oracle Database MCQ Quiz Model Test

Explanation
The given SQL statement SELECT id, last_name, first_name, commission*1.5 FROM employee WHERE commission 0; provides two of the desired results. It displays the commission multiplied by 1.5, as requested in the first desired result. It also excludes employees with zero commission by using the WHERE clause with the condition commission 0, as stated in the second desired result. However, it does not display a zero for employees with a null commission value, which is the third desired result.

Explanation
The best way to modify the view to contain only those patients born in 1997 is by replacing the view and adding a WHERE clause. This allows us to filter the data and include only the patients who were born in 1997.

Explanation
The table name "Catch_#22" is valid because it follows the rules for naming tables in a database. Table names can contain letters, numbers, and underscores, but cannot start with a number or contain special characters like "#" or "-". Therefore, "Catch_#22" is the only option that meets these criteria.

Explanation
The user cannot go into SQL* PLUS and query the USER_TRIGGERS data dictionary view to see the compilation error that occurs during the compilation of a trigger. The USER_TRIGGERS view provides information about triggers in the user's schema, but it does not include details about compilation errors. To see compilation errors, the user can check the error logs or error messages generated during the compilation process.

Explanation
The 'Where' clause is used to compare two values by specifying a condition that needs to be met for the rows to be included in the result set. It is also used to restrict the rows displayed by specifying certain criteria that the rows must satisfy. Additionally, it can be used to only display data greater than a specified value by using comparison operators such as '>', '=', or '

Explanation
The three SQL arithmetic expressions that return a date are '08-jul-96' + 7, '01-jul-96' - 12, and '03-jul-96' + (12/24). These expressions perform addition and subtraction operations on the given dates, resulting in a new date value. The first expression adds 7 days to the date '08-jul-96', the second expression subtracts 12 days from the date '01-jul-96', and the third expression adds 12 hours (12/24) to the date '03-jul-96'.

Explanation
TIMESTAMP, INTERVAL DAY TO SECOND, and INTERVAL YEAR TO MONTH are the three DATETIME data types that can be used when specifying column definitions. The TIMESTAMP data type is used to store date and time values, while INTERVAL DAY TO SECOND is used to store intervals of time in days, hours, minutes, and seconds. INTERVAL YEAR TO MONTH is used to store intervals of time in years and months. These data types provide flexibility in storing and manipulating date and time data in a database.

Explanation
The correct answer is SELECT TO CNAR(2000, '$0,000.00') FROM dual;, SELECT TO CNAR(2000, '$9,999.00') FROM dual;, SELECT TO CNAR(2000, '$9,999.99') FROM dual; These three SELECT statements will display 2000 in the format "$2,000.00" because the TO_CHAR function is used to convert the number 2000 into a character string with the specified format. The format '$0,000.00' specifies that the number should be displayed with a dollar sign, comma as a thousands separator, and two decimal places.

Explanation
The statement "Contents of the packages can be shared by many applications" is true. In software development, packages are used to organize and group related classes, interfaces, and other components. These packages can be accessed and used by multiple applications, allowing for code reusability and modularity. This promotes efficient development and maintenance of software systems by enabling the sharing and collaboration of resources among different applications.

Explanation
Information hiding is a principle in software engineering that aims to restrict access to certain parts of a program, allowing only necessary information to be exposed. By making package constructs private, we can control the visibility of these constructs within the package, preventing external access and achieving information hiding. This ensures that the implementation details of the package are hidden from other parts of the program, promoting encapsulation and reducing dependencies. Therefore, the statement "YOU can achieve information hiding by making package constructs private" is true.

Explanation
A CALL statement inside the trigger body allows you to invoke a stored procedure. This means that when the trigger is triggered, it can execute a specific stored procedure, which can perform a series of predefined actions or operations. This enables you to have more control and flexibility in managing and manipulating data within the database. By calling a stored procedure from a trigger, you can automate complex tasks and ensure consistency in data manipulation.

Explanation
The statement is true because constants, which are fixed values that do not change during program execution, can be organized and grouped within packages. Packages provide a way to organize related classes and interfaces, and constants can be declared within these classes or interfaces. By grouping constants within packages, it becomes easier to manage and access them within the program. Therefore, the correct answer is true.

Explanation
In SQL, when sorting data in ascending order, Null values are displayed last. This means that if there are Null values in a column being sorted, they will appear at the bottom of the result set. This behavior is consistent across most SQL database systems and can be useful for identifying missing or incomplete data.

Explanation
If the ORDER BY clause is not provided in an SQL query, the results are not necessarily sorted by the first column in the SELECT list. The order in which the results are returned is not guaranteed and can vary depending on the database system or other factors.

Explanation
False. It is possible to sort query results by a column that is not included in the SELECT list. The SELECT list determines the columns that will be returned in the result set, but it does not restrict the ability to sort by other columns in the table.

Explanation
The privilege that concerns with system level security is the DROP privilege. This privilege allows a user to delete or drop any table in the database. It is a powerful privilege that should only be granted to trusted users, as it can potentially cause data loss or disruption to the system. The other options, DELETE, ALTER, INDEX, and UPDATE, are privileges that are related to manipulating data or modifying database objects, but they do not have the same level of impact on system security as the DROP privilege.

Explanation
In a cursor for loop, the user does not need to explicitly open, fetch, or close a cursor. The cursor for loop automatically performs these actions internally. This loop is designed to simplify the process of iterating through the result set of a query by handling the cursor operations behind the scenes. Therefore, the statement "The user do not explicitly open, fetch or close a cursor within a cursor for loop" is true.