Name error-trapping functions. How are they useful?

What will be an ideal response?

When an exception occurs in your program, you don’t know the error code for the error
and its associated message unless you take specific action to identify the error code. Then,
once you know the error code and the message, you can modify your program to take
action based on the error. The two functions to identify the error code and error message
are
? SQLCODE. The SQLCODE function returns negative error code number. The number
can be assigned to a variable of NUMBER type.
? SQLERRM. The SQLERRM function returns the error message associated with the error
code. The maximum length of error message is 512 bytes. It can be assigned to a
VARCHAR2 type variable.