Declares an exception handler. An exception handler may be
declared to respond to a specific exception condition or one or
more of the exception class groups SQLEXCEPTION, SQLWARNING or
NOT FOUND. An exception handler that responds to one or more
exception class groups is called a general exception handler. A
specific exception condition may be specified by using an
SQLSTATE value or a condition name, see DECLARE CONDITION. An
exception handler that responds to one or more specific
exception conditions is called a specific exception handler. The
keywords CONTINUE, EXIT and UNDO affect the flow of control
behavior subsequent to the execution of the exception handler.
If CONTINUE is specified, the flow of control continues by
executing the SQL statement immediately following the statement
that raised the error, after the handler has executed. If EXIT
is specified, the flow of control exits the compound statement
within which the exception handler is declared after the handler
has executed. If UNDO is specified,