Thread: xml_valid function
Not sure what the correct forum for pgxml/xml2 questions is. I was wondering what is the definition of "valid" that the xml_valid(text) function that is part of that module uses? It seems different from the W3C definition of "valid" XML (is there an implicit DTD?) Maybe it is more akin to "well-formed"? George
On Wed, 25 Jan 2006 17:11:04 -0800, George Pavlov wrote: > Not sure what the correct forum for pgxml/xml2 questions is. I was > wondering what is the definition of "valid" that the xml_valid(text) > function that is part of that module uses? It seems different from the > W3C definition of "valid" XML (is there an implicit DTD?) Maybe it is > more akin to "well-formed"? > It is indeed well-formed. That just seemed a long name for the function! Regards John
John Gray wrote on
Friday, January 27, 2006 12:24 PM
> On Wed, 25 Jan 2006 17:11:04 -0800, George Pavlov wrote:
>
>> Not sure what the correct forum for pgxml/xml2 questions is. I was
>> wondering what is the definition of "valid" that the xml_valid(text)
>> function that is part of that module uses? It seems different from the
>> W3C definition of "valid" XML (is there an implicit DTD?) Maybe it is
>> more akin to "well-formed"?
>>
>
> It is indeed well-formed. That just seemed a long name for the function!
>
> John
Valid means it's been checked against, and conforms to, a DTD. If it hasn't been then it can't
be said to be valid.
-Roger
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On Fri, 2006-01-27 at 12:32 -0800, Roger Hand wrote: > John Gray wrote on > Friday, January 27, 2006 12:24 PM > > On Wed, 25 Jan 2006 17:11:04 -0800, George Pavlov wrote: > > > >> Not sure what the correct forum for pgxml/xml2 questions is. I was > >> wondering what is the definition of "valid" that the xml_valid(text) > >> function that is part of that module uses? It seems different from the > >> W3C definition of "valid" XML (is there an implicit DTD?) Maybe it is > >> more akin to "well-formed"? > >> > > > > It is indeed well-formed. That just seemed a long name for the function! > > > > John > > Valid means it's been checked against, and conforms to, a DTD. If it hasn't been then it can't > be said to be valid. > I know that - my point was just that when I was naming the functions, I (perhaps foolishly, in hindsight) decided that xml_wellformed seemed a longish name for a basic function. The README does in fact state that it checks well-formedness and not validity. It's easily changed in the SQL file if you'd rather have a different name for your installation. As for changing it in the distribution, I can see some backward-compatibility issues (I suspect it may be in production use under that name) - but if there were to be a version which validated a document against a DTD it would be a two parameter version which would therefore have a different signature for PG. Regards John
On Fri, 2006-01-27 at 15:21, John Gray wrote: > I know that - my point was just that when I was naming the functions, I > (perhaps foolishly, in hindsight) decided that xml_wellformed seemed a > longish name for a basic function. The README does in fact state that it > checks well-formedness and not validity. It's easily changed in the SQL > file if you'd rather have a different name for your installation. > > As for changing it in the distribution, I can see some > backward-compatibility issues (I suspect it may be in production use > under that name) - but if there were to be a version which validated a > document against a DTD it would be a two parameter version which would > therefore have a different signature for PG. A lot of validators make it clear that you can validate xml with or without a DTD. So, it makes sense to have an overloaded xml_valid() function that accepts a single argument (plain xml) and a two parter that takes xml and a dtd as the two arguments.