Oracle has a large set of predefined exceptions.
A few of the most common predefined exceptions are named such as ZERO_DIVIDE.
All named exceptions have codes.
In the exception-handling block, you will usually refer to them by using their more user-friendly names.
A few of the most important ones are mentioned here:
|Name|| Number|| Description|
|INVALID_NUMBER|| ORA-01722|| Conversion of string to number failed.|
|VALUE_ERROR|| ORA-06502|| Generic error indicating that there is an inconsistency between the variable and its value.|
|DUP_VAL_ON_INDEX|| ORA-00001|| attempting to store duplicate values in a database column that is constrained by a unique index.|
If the exception is unnamed, to handle the exception use the SQLCODE function.