Schema question regarding some mandatory/some optional values

[Piers Chivers]

Hi,
I have XML like

<SomeElement>
<Value>5</Value>
<Value>3</Value>
<Value>7</Value>
</SomeElement>

I want to define the schema to say that the <Value>s must contain at least
one of a number of known values, and may contain some other <Value>s. For
example, if the known <Value>s were 3 and 5 then the above is valid. Also,

<SomeElement>
<Value>5</Value>
<Value>1</Value>
</SomeElement>

AND

<SomeElement>
<Value>3<Value>
</SomeElement>

are valid because they contain one of (3 and 5). But

<SomeElement>
<Value>8</Value>
</SomeElement>

is not valid. I've tried defining this using xs:all and enumerations but
with no luck. All suggestions gratefully received.

Thanks,
Piers

 

[Martin SChukrazy]

One suggestion is to change the
<Value>5</Value>
to a
<Value5>...</Value5>
That way you can have multiple values i.e. each value is equal to an element
and hence write a DTD/Schema that makes it conform to your rules defined
below...

 

[Piers Chivers]

I don't think this can work. It doesn't feel instinctively right (not that
my XML instincts are particularly good!). The mian problem though is that I
don't know what all of the possible values are. I might have a Value1002 or
Value27649 etc. How do I represent this in a schema?

I'm surprised this is so difficult. I would have thought that a schema that
said "Many values allowed but at least one of them must be blahblah" isn't
such an unusual request??

Piers