Database and SQL

Forced view is used for the table, which are not created. This concept is required for bigger programs, where many people are working on the same project.

This is the correct syntax of the function used to print on screen.

%rowtype is used to select entire row of a table. It does not consider the datatype of the individuals cells.

This will give all data of emp table only where Job is Manager.

This is the correct SQL statement to find the specified fields with the virtual column.

Incorrect option

Rest will be assigned with NULL.

It is not a cursor attribute.

When a PL/SQL procedure has compilation errors, SQL*Plus displays a warning message but does not automatically show the errors. The DBA or developer must explicitly execute the 'SHOW ERRORS' command to view the compilation error details, including line numbers and error messages. Option A is incorrect because SQL*Plus renumbers lines starting from 1, not matching your editor. Option B is false because errors aren't shown automatically. Option D is incorrect - successful compilation produces no warning message.

In SQL*Plus, a semicolon followed by the Enter key signals that the SQL statement is complete and ready for execution. The semicolon acts as a statement terminator in SQL*Plus. Option A is incorrect - a forward slash (/) executes statements in the buffer but doesn't terminate statement entry. Option B's colon is used for bind variables, not statement termination. Option D's period has no special meaning in SQL*Plus statement termination.

ALTER TABLE is the standard SQL command for modifying the structure of an existing table. This includes adding, dropping, or modifying columns, constraints, and other table properties. UPDATE TABLE is used for modifying data within a table, not its structure. MODIFY TABLE and CHANGE TABLE are not valid SQL commands in any major database system.

SQL*Plus and Oracle database identifiers are case-insensitive by default. This means 'SELECT', 'select', and 'Select' are treated identically, and table/column names like 'Employee' and 'employee' refer to the same object. This case-insensitivity applies unless quoted identifiers are used, in which case they become case-sensitive. The default behavior makes SQL*Plus more user-friendly and less prone to typing errors.

The semicolon is the standard SQL statement terminator in SQL*Plus. When you type a semicolon and press Enter, SQL*Plus recognizes the statement as complete and executes it. The forward slash (/) is used to execute the contents of the SQL buffer, not terminate a new statement. The colon (:) is used for bind variables in SQL*Plus. The period (.) is used in some SQL implementations but not in Oracle SQL*Plus for statement termination.

The query will return an error because DISTINCT cannot be used for individual columns in a SELECT statement - it must apply to all selected columns or the entire row. The syntax 'select enpno, DISTINCT ename, Salary' is invalid because DISTINCT must come before the column list and apply to the combination of all columns, not just one column.

The 'Update Only If NULL' property ensures that a field can only be updated when it has no value (is NULL). Once a value is entered, it cannot be modified. This is perfect for the shipping date scenario - clerks can enter the date initially, but once saved, it becomes read-only. 'Enabled' controls whether the item can receive focus, 'Database Item' indicates if it's stored in the database, and 'Update Allowed' is a binary on/off setting.