except Exception, e:

            msg = strings.ustr(e.args[0])

            msg = re.sub(r'^(?:PL/Python: )?ValueError: ', r'', msg)

            match = re.match(r'^invalid byte sequence for encoding "(.+?)":',

                msg)

            if match:

                encoding, = match.groups()

                raise EncodingException(encoding, e)

            match = re.match(r'^duplicate key value violates unique constraint '

                r'"(.+?)"', msg)

            if match:

                constraint, = match.groups()

                cols = []

                cond = None

                if recover: # need auto-rollback to run index_cols()

                    try:

                        cols = index_cols(db, constraint)

                        cond = index_cond(db, constraint)

                    except NotImplementedError: pass

                raise DuplicateKeyException(constraint, cond, cols, e)

            match = re.match(r'^null value in column "(.+?)" violates not-null'

                r' constraint', msg)

            if match:

                col, = match.groups()

                raise NullValueException('NOT NULL', None, [col], e)

            match = re.match(r'^new row for relation "(.+?)" violates check '

                r'constraint "(.+?)"', msg)

            if match:

                table, constraint = match.groups()

                constraint = sql_gen.Col(constraint, table)

                cond = None

                if recover: # need auto-rollback to run constraint_cond()

                    try: cond = constraint_cond(db, constraint)

                    except NotImplementedError: pass

                raise CheckException(constraint.to_str(db), cond, [], e)

            match = re.match(r'^(?:invalid input (?:syntax|value)\b.*?'

                r'|.+? out of range): "(.+?)"', msg)

            if match:

                value, = match.groups()

                raise InvalidValueException(strings.to_unicode(value), e)

            match = re.match(r'^column "(.+?)" is of type (.+?) but expression '

                r'is of type', msg)

            if match:

                col, type_ = match.groups()

                raise MissingCastException(type_, col, e)

            match = re.match(r'^could not determine polymorphic type because '

                r'input has type "unknown"', msg)

            if match: raise MissingCastException('text', None, e)

            match = re.match(r'^.+? types .+? and .+? cannot be matched', msg)

            if match: raise MissingCastException('text', None, e)

            typed_name_re = r'^(\S+) "(.+?)"(?: of relation ".+?")?'

            match = re.match(typed_name_re+r'.*? already exists', msg)

            if match:

                type_, name = match.groups()

                raise DuplicateException(type_, name, e)

            match = re.match(r'more than one (\S+) named ""(.+?)""', msg)

            if match:

                type_, name = match.groups()

                raise DuplicateException(type_, name, e)

            match = re.match(typed_name_re+r' does not exist', msg)

            if match:

                type_, name = match.groups()

                raise DoesNotExistException(type_, name, e)

            raise # no specific exception raised