PL/SQL Interview Questions and Answers Part 4
21. What is the purpose of WHEN clause in trigger?
Answer:
A WHEN clause specifies the condition that must be true for the trigger to be triggered.
22. What are the different schema objects that can be created using PL/SQL?
Answer:
- Packages
- Triggers
- Cursors
- Stored procedures
- Functions
23. Explain the purpose of cursor attribute SQL%ROWCOUNT, SQL%FOUND and SQL%NOTFOUND?
Answer:
SQL%ROWCOUNT: It returns the number of rows that are processed by a SQL statement.
SQL%NOTFOUND: It returns the Boolean value TRUE if at least one row was processed.
SQL%NOTFOUND: It returns the Boolean value TRUE if no rows were processed.
24. Write a command to delete a package.
Answer:
DROP PACKAGE
25. What are the three basic sections of a PL/SQL block?
Answer:
- Declaration section
- Execution section
- Exception section
26. What is a MERGE statement?
Answer:
The MERGE statement inserts or updates rows in one table, using data from another table. It is useful in data warehousing applications.
