XSD Validation Question

[John Viele]

To you XML validation experts:

I have a schema that validates an XML file, but there are a couple of other
types of validation I'd like to do on it. They are basically string fields
that must be validated against a set of possible codes, but there could be
tens of thousands of possible codes. Naturally, these codes are in a table
in SQL (actually there are a few code types, but the problem is the same for
each).

In the past I have always done this as an additional code step AFTER schema
validation, but I am being asked whether it could be "plugged into" the
schema validation step.

I've taken a look at the XmlDataDocument class which seems to indicate that
I could read a SQL table into a Dataset and use this class to allow XSD
schema validation to reference the range of possible values for the field
type.

Do you have any thoughts on this approach? Could it be made to work and do
you think it would be a "performance pig" ?

[John Viele]

Maybe this is obvious, but to clarify: the type of validation I am talking
about is like an XSD enumeration, but compared against a set of values in a
SQL database table.

-jv

[Oleg Tkachenko]

John Viele wrote:

I have a schema that validates an XML file, but there are a couple of other
types of validation I'd like to do on it. They are basically string fields
that must be validated against a set of possible codes, but there could be
tens of thousands of possible codes. Naturally, these codes are in a table
in SQL (actually there are a few code types, but the problem is the same for
each).

In the past I have always done this as an additional code step AFTER schema
validation, but I am being asked whether it could be "plugged into" the
schema validation step.

I've taken a look at the XmlDataDocument class which seems to indicate that
I could read a SQL table into a Dataset and use this class to allow XSD
schema validation to reference the range of possible values for the field
type.

You can build schema definition for that enumeration on the fly querying
information from database, then including this subschema into main one:
<xs:include schemaLocation="http://server.com/foo.aspx"/>
Then you'd better cache compiled scemas using XmlSchema object.
Alternatively you can plug in your custom validation just before schema
validation - using custom filtering XmlReader, which reads XML as is, but
validates internally certain elements.
--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel