Re: [regrep] [XML Schema issue] Replace choice with type substitution

From
Farrukh Najmi <>
Date
2003-03-14T20:12:54+00:00
ID
Thread
Re: [regrep] [XML Schema issue] Replace choice with type substitution
Attached is the changes to rim.xsd if we went ahead with the proposed 
change. The lines starting with '-' are being removed. The line starting 
with '+' are being added. Other lines are shown for visual context.

Notice how much cleaner the schema gets.

Farrukh Najmi wrote:

>
> Team,
>
> In new V3 schema we have consistently used type substitution instead 
> of choice construct when defining XMl schema. Choice in the pinion of 
> many is not very object oriented and implementation experience has 
> shown that it complicates design.
>
> I would like to ask if any one has objections if we replace 
> occurrences of <choice> in the schema with type substitution. Here is 
> an example of how teh proposal effects the schema:
>
> Old Way
> --------
> In query.xsd the definition of AdhocQueryRequest looks like:
>
> <sequence>
>   <element ref = "tns:ResponseOption" minOccurs="1" maxOccurs="1" />
>   <choice minOccurs="1" maxOccurs="1">
>     <element ref = "tns:FilterQuery"/>
>     <element ref = "tns:SQLQuery"/>
>   </choice>
> </sequence>
>
> New Way
> -------
> Above Old Way would look like this under the proposal:
>
> <sequence>
>   <element ref = "tns:ResponseOption" minOccurs="1" maxOccurs="1" />
>   <element name="Query" type="tns:AdhocQueryType" minOccurs="1" 
> </sequence>
>
> Where AdhocQueryType is the base type for both SQLQueryType and 
> FilterQueryType.
>
> Benefits
> ---------
> Now code can be written using Object oriented principals so that there 
> is a AdhocQueryType class that is extended by SQLQueryType and 
> FilterQueryType classes. Either type of query may be abstractly 
> represented as a AdhocQueryType.
>
> Thanks for your input on this issue.
>
>
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-- 
Regards,
Farrukh