Re: What does "optional" mean?
On 26/02/2012 16:16, Costello, Roger L. wrote: > That is, what is it about some information that it is declared > mandatory whereas another information is declared optional? making the element optional in the schema has nothing (much) to do with whether the information is required. If the information is a boolean value it is purely syntactic choice whether true and false are: <foo val="yes"/> <foo val="no"/> <foo val="anything" <foo/> so you can mark truth by the _presence_ of the attribute, which means marking it optional in the schema. think <input selected=""/> in xhtml. The lack of the attribute in such a case is not lack of information, it is asserting the effective value is false. Or it may just be that the same element has multiple roles <a id="gf"/> or <a href=khgf">...</a> in xhtml, mean that (in some schema languages href and id have to be marked as optional) really it's like asking when would you begin an element name with "a" and when with "b". It's a choice that has to be made and recorded in the schema but it typically has no particular meaning or reason behind the choice. David
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format