Menu
I wasn't aware of a difference, but a coworker says there is, although he can't back it up. What's the difference if any?
288
The difference between well-formed and valid XML is simple: Valid XML has a DTD associated with it and has been verified against all the rules contained in the DTD in addition to being well-formed. Merely well-formed XML, on the other hand, is not necessarily valid, although it may be.
An XML document with correct syntax is called "Well Formed". An XML document validated against a DTD is both "Well Formed" and "Valid".
If an XML document is not well-formed, an XML processor signals an error and stops normal processing. It is crucial that you understand the well-formedness constraints in XML 1.0, to ensure that the XML documents that you create will be processed correctly and without errors.
XML validation is the process of checking a document written in XML (eXtensible Markup Language) to confirm that it is both well-formed and also "valid" in that it follows a defined structure. A well-formed document follows the basic syntactic rules of XML, which are the same for all XML documents.
There is a difference, yes.
XML that adheres to the XML standard is considered well formed, while xml that adheres to a DTD is considered valid.
79
Well-formed means that a textual object meets the W3C requirements for being XML.
Valid means that well-formed XML meets additional requirements given by a specified schema.
Per the W3C Recommendation for XML:
[Definition: A data object is an XML document if it is well-formed, as defined in this specification. In addition, the XML document is valid if it meets certain further constraints.]
Not well-formed:
<a><b></a></b> < or & are used in content rather than < or &.Invalid
Technically, colon characters are permitted in component names in XML. However, colons should only be used in names for namespace purposes:
Note:
The Namespaces in XML Recommendation [XML Names] assigns a meaning to names containing colon characters. Therefore, authors should not use the colon in XML names except for namespace purposes, but XML processors must accept the colon as a name character.
Therefore, another term, namespace-well-formed, is defined in the Namespaces in XML 1.0 W3C Recommendation that implies all of the XML rules for well-formedness plus those governing namespaces and namespace prefixes.
Colloquially, the term well-formed is often used where namespace-well-formed would be more precise. However, this is a minor technical manner of less practical consequence than the distinction between well-formed vs valid XML described in this answer.
28
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
