Hi Fellows:

Last week I had posted a message about ODBC's reliability, security, complexity etc,.... Now the vendor that I am dealing with is suggesting that because ODBC is not very reliable, secure etc., we can have an XML interface on the SCADA machine and talk ODBC to it within the same physical box and then talk to the other machines using XML. He thinks that XML is a lot more secure and that is what should be used.

I am not sure if "XML" itself is a communication protocol. My understanding is that XML is nothing more than a method of putting structured data in text files. XML itself may be using some other
underlying communication protocol.

I think by comparing XML with ODBC he is comparing Apples with Oranges. Plus what is the guaranty that XML link will work better than ODBC.

Any help on this issue will be appreciated:

Thanks.

 

Ditch this vendor and find someone else. He either has no understanding of what is going on, or he is trying to milk you for everything he can. Either way, this is not the type of person to
EVER ALLOW INTO YOUR PLANT AGAIN!!!!

 

> Last week I had posted a message about ODBC's reliability,
> security, complexity etc,.... Now the vendor that I am dealing with
> is suggesting that because ODBC is not very reliable, secure etc., we
> can have an XML interface on the SCADA machine and talk ODBC to it
> within the same physical box and then talk to the other machines using
> XML. He thinks that XML is a lot more secure and that is what should
> be used.

Your vendor is a little confused.

XML is not "secure". XML ignores security. It is a method of representing data. XML is no more a replacement for ODBC than Modbus is for OPC. ODBC is essentially an API (there are more elements than just an API but please allow me to generalize a little) that allows Windows applications to interact with RDBMS without having to know the brand of RDBMS.

> I am not sure if "XML" itself is a communication protocol. My
> understanding is that XML is nothing more than a method of putting
> structured data in text files.

XML is a data representation language. XML could be used to express a protocol but it is not a protocol in and of itself.

> XML itself may be using some other underlying communication
> protocol.

XML **REQUIRES** using some other underlying communications protocol.

> I think by comparing XML with ODBC he is comparing Apples with
> Oranges.

More like apples and tree ladders.

> Plus what is the guaranty that XML link will work better than
> ODBC.

This assumes that the claim that ODBC doesn't work is true. ODBC does work.

If you want to know more about XML, here is a pretty good overview article that describes XML concepts succinctly (albeit from an IT
perspective):

http://www.sunworld.com/swol-06-1999/swol-06-itarchitect.html

Regards,
Ralph Mackiewicz
SISCO, Inc.

 

This guy is probably talking about the feature that allows you to receive database query results back in XML format. This is an extension of OLE-DB, which does provide several advantages over
ODBC. Before totally writing the guy off, I would investigate for yourself the advantages of OLE-DB with XML versus ODBC. Personally, I would choose this route over ODBC. Your vendor may be referring to "XML" as a generic term for the XML/OLE-DB combination. It may not necessarily indicate that he is a complete moron. Of course, I still wouldn't rule that out. I would just investigate things a bit more.