Oracle Error PLS-01913: : instance must of be of type ‘string’ or one of its subtypes

Oracle Error Message

PLS-01913: : instance must of be of type ‘string’ or one of its subtypes

Reason for the Error

The run-time type of the instance is the not declared type or one of its subtypes. e.g. TREAT(supertype AS subtype) fails.

Solution

Catch the exception.