Re: [xml-dev] What is the difference between XSD and DTD

["Michael Fisher" <fish@elephantdrive.com>]

Depending on what platform you develop on, XSD can easily be used to validate XML from an unknown (or simply un-trustworthy in terms of well-formed XML) source, if you have a copy of the schema to validate it against.  For example, in .NET you can use XmlValidatingReader object to compare incoming XML against a schema in the form of XSD or DTD.  You can even extract an XSD that is sent to you and validate based on that.

-----Original Message-----
From: Michael Kay [mailto:mike@saxonica.com]
Sent: Wednesday, April 27, 2005 04:27 PM
To: ''Saha Rabindra N'', xml-dev@lists.xml.org
Subject: RE: [xml-dev] What is the difference between XSD and DTD

In terms of validation functionality, XSD can define all the constraints that a DTD can define, and many more. To take a simple example, XSD can say that a particular attribute must be a valid date, or a number, or a list of URIs, or a string that is exactly 8 characters long. To take another example, XSD can define much richer constraints on uniqueness of values within a document.

 

I've no idea what you mean by "cross validate". I believe the only things you can do with a DTD that you can't do with an XML Schema are things that have nothing to do with validation: notably, defining entities.

 

Michael Kay

http://www.saxonica.com/

---

From: Saha Rabindra N [mailto:saha.rn@mellon.com]
Sent: 27 April 2005 22:10
To: xml-dev@lists.xml.org
Subject: [xml-dev] What is the difference between XSD and DTD
Importance: High

Hello,

  Can anybody please explain me the real difference between XSD and DTD. Because both are used to define the schema of an XML document.

Whereas DTD is more powerful in the sense that XML parser can cross validate an XML document based on its DTD, and this is really useful in business world as XML is mostly used to exchange the data between parties.

On the other hand XSD defines the schema in XML syntax only which is more readable, but XML parser CAN NOT cross validate one XML document based on a given XSD.

 

Then I am not understanding why people go for XSD ?

 

Can some body correct me please !

Thanks in advance,

 

Regards,

Rabindra Nath Saha

 

 

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