@Override
    public JdbcDeserializationConverter createInternalConverter(LogicalType type) {
        switch (type.getTypeRoot()) {
            case NULL:
                return val -> null;
            case BOOLEAN:
                return val -> val instanceof NUMBER ? ((NUMBER) val).booleanValue() : val;
            case FLOAT:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).floatValue()
                        : val instanceof BINARY_FLOAT
                                ? ((BINARY_FLOAT) val).floatValue()
                                : val instanceof BigDecimal
                                        ? ((BigDecimal) val).floatValue()
                                        : val;
            case DOUBLE:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).doubleValue()
                        : val instanceof BINARY_DOUBLE
                                ? ((BINARY_DOUBLE) val).doubleValue()
                                : val instanceof BigDecimal
                                        ? ((BigDecimal) val).doubleValue()
                                        : val;
            case TINYINT:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).byteValue()
                        : val instanceof BigDecimal ? ((BigDecimal) val).byteValue() : val;
            case SMALLINT:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).shortValue()
                        : val instanceof BigDecimal ? ((BigDecimal) val).shortValue() : val;
            case INTEGER:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).intValue()
                        : val instanceof BigDecimal ? ((BigDecimal) val).intValue() : val;
            case BIGINT:
                return val -> val instanceof NUMBER
                        ? ((NUMBER) val).longValue()
                        : val instanceof BigDecimal ? ((BigDecimal) val).longValue() : val;
            case DECIMAL:
                final int precision = ((DecimalType) type).getPrecision();
                final int scale = ((DecimalType) type).getScale();
                return val -> val instanceof BigInteger
                        ? DecimalData.fromBigDecimal(
                                new BigDecimal((BigInteger) val, 0), precision, scale)
                        : DecimalData.fromBigDecimal((BigDecimal) val, precision, scale);
            case CHAR:
            case VARCHAR:
                return val -> (val instanceof CHAR)
                        ? StringData.fromString(((CHAR) val).getString())
                        : (val instanceof OracleClob)
                                ? StringData.fromString(((OracleClob) val).stringValue())
                                : StringData.fromString((String) val);
            case BINARY:
            case VARBINARY:
            case RAW:
                return val -> val instanceof RAW
                        ? ((RAW) val).getBytes()
                        : val instanceof OracleBlob
                                ? ((OracleBlob) val)
                                        .getBytes(1, (int) ((OracleBlob) val).length())
                                : val.toString().getBytes();

            case INTERVAL_YEAR_MONTH:
            case INTERVAL_DAY_TIME:
                return val -> val instanceof NUMBER ? ((NUMBER) val).intValue() : val;
            case DATE:
                return val -> val instanceof DATE
                        ? (int) (((DATE) val).dateValue().toLocalDate().toEpochDay())
                        : val instanceof Timestamp
                                ? (int) (((Timestamp) val)
                                        .toLocalDateTime()
                                        .toLocalDate()
                                        .toEpochDay())
                                : (int) (((Date) val).toLocalDate().toEpochDay());
            case TIME_WITHOUT_TIME_ZONE:
                return val -> val instanceof DATE
                        ? (int) (((DATE) val).timeValue().toLocalTime().toNanoOfDay()
                                / 1_000_000L)
                        : (int) (((Time) val).toLocalTime().toNanoOfDay() / 1_000_000L);
            case TIMESTAMP_WITHOUT_TIME_ZONE:
                return val -> val instanceof TIMESTAMP
                        ? TimestampData.fromTimestamp(((TIMESTAMP) val).timestampValue())
                        : TimestampData.fromTimestamp((Timestamp) val);
            case TIMESTAMP_WITH_TIME_ZONE:
                return val -> {
                    if (val instanceof TIMESTAMPTZ) {
                        final TIMESTAMPTZ ts = (TIMESTAMPTZ) val;
                        final ZonedDateTime zdt =
                                ZonedDateTime.ofInstant(
                                        ts.timestampValue().toInstant(),
                                        ts.getTimeZone().toZoneId());
                        return TimestampData.fromLocalDateTime(zdt.toLocalDateTime());
                    } else {
                        return TimestampData.fromTimestamp((Timestamp) val);
                    }
                };
            case ARRAY:
            case ROW:
            case MAP:
            case MULTISET:
            default:
                return super.createInternalConverter(type);
        }
    }
Runtime converter that responsible to convert between JDBC object and Flink internal object for Oracle.
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/jdbc/src/main/java/org/apache/inlong/sort/jdbc/converter/oracle/OracleRowConverter.java