In Oracle PL/SQL, define the four standard cursor attributes %FOUND, %NOTFOUND, %ROWCOUNT, and %ISOPEN, and explain what each one indicates about cursor state.

Introduction / Context:When working with explicit cursors or cursor variables in PL/SQL, you need to know whether a cursor is open, whether the last fetch returned a row, and how many rows have been processed. Oracle provides cursor attributes for this purpose. This question focuses on the four standard attributes and what they mean in PL/SQL code.

Given Data / Assumptions:

• We are using explicit cursors or relying on implicit cursors created for SQL statements in PL/SQL.• We want to control loops and logic based on success or failure of fetch operations or DML statements.• Oracle defines standard attributes that can be appended to cursor names or to SQL for the implicit cursor.• These attributes are %FOUND, %NOTFOUND, %ROWCOUNT, and %ISOPEN.

Concept / Approach:%FOUND and %NOTFOUND are Boolean attributes that indicate whether the last fetch or DML statement affected any rows. %FOUND becomes true when a fetch successfully returns a row or when a DML statement affects at least one row, and false otherwise. %NOTFOUND is the logical opposite of %FOUND. %ROWCOUNT is a numeric attribute that reports how many rows have been processed so far by the cursor or DML statement. %ISOPEN tells you whether an explicit cursor is currently open, which helps avoid opening a cursor twice or fetching from a closed cursor.

Step-by-Step Solution:Step 1: For the implicit cursor SQL, SQL%FOUND indicates whether the last INSERT, UPDATE, DELETE, or SELECT INTO affected or returned any rows.Step 2: SQL%NOTFOUND is true when the last DML or SELECT INTO did not affect or return any rows, which is useful for detecting missing data.Step 3: SQL%ROWCOUNT gives the number of rows affected by the last DML statement, which is commonly used for logging and validation.Step 4: For an explicit cursor cur_emp, cur_emp%ISOPEN is true if the cursor has been opened and not yet closed, and false otherwise.Step 5: These behaviours match the description in option A and allow PL/SQL code to manage cursor based loops safely.

Verification / Alternative check:If you write a loop that fetches rows from an explicit cursor, you can use EXIT WHEN cur_emp%NOTFOUND; to terminate when no more rows are available. Observing that %ROWCOUNT increments with each fetch confirms that it tracks progress. Testing SQL%FOUND after an UPDATE shows whether any rows satisfied the WHERE clause, which verifies the semantics of the implicit cursor attributes.

Why Other Options Are Wrong:Option B assigns completely unrelated meanings to the attributes and is incorrect. Option C states that cursor attributes are only for SQL Plus, which is false because they are part of PL/SQL. Option D misuses %ISOPEN and claims it returns error text, which is handled by exceptions instead.

Common Pitfalls:One pitfall is checking %FOUND without performing a fetch first, which leads to unpredictable results. Another is misunderstanding the difference between implicit SQL attributes and explicit cursor attributes. Careful coding patterns, such as always fetching before checking %NOTFOUND in a loop, help avoid off by one errors and missed rows.

Final Answer:%FOUND is true after a successful fetch or DML affecting at least one row, %NOTFOUND is the opposite, %ROWCOUNT shows how many rows have been processed so far, and %ISOPEN indicates whether the cursor is currently open.