TajoDataTypes.Type dataType = schema.getColumn(fieldId - 1).getDataType().getType();
switch(dataType) {
case BOOLEAN: return d.asBool();
case INT1:
case INT2: return d.asInt2();
case INT4: return d.asInt4();
case INT8: return d.asInt8();
case TEXT:
case CHAR:
case DATE: