Strongly typed dataset for hierarchical data

[Oleg Ogurok]

Hi all,

I'm trying to create a simple XML structure for storing tree-stryle data for
a forum-like software, e.g. each post will have a body field, the ID of the
user who posted the message, and zero or more subposts(replies). Thus it
would allow for unlimited depth of subposts.

I also need a simple table to store UserID, Full Name, etc of the users
posting messages.

I've created a schema in VS.NET 2003 as follows. However, now I need to add
a relation between ID field of User table and UserID field of Post table
(one-to-many). If I try to add such relation, I get "Failed to add data
relation. Exception has been thrown by the target of an invocation."

Any help is greatly appreciated.

----------------------
<?xml version="1.0" encoding="utf-8" ?>

<xs:schema id="DsPost" targetNamespace="http://tempuri.org/DsPost.xsd"
elementFormDefault="qualified"

attributeFormDefault="qualified" xmlns="http://tempuri.org/DsPost.xsd"
xmlns:mstns="http://tempuri.org/DsPost.xsd"

xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">

<xs:element name="DsPost" msdata:IsDataSet="true">

<xs:complexType>

<xs:choice maxOccurs="unbounded">

<xs:element name="Post">

<xs:complexType>

<xs:sequence>

<xs:element name="Body" type="xs:string" minOccurs="0" />

<xs:element name="UserID" type="xs:int" minOccurs="0" />

<xs:element name="Post" type="PostType" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:element>

<xs:element name="User">

<xs:complexType>

<xs:sequence>

<xs:element name="ID" type="xs:int" minOccurs="0" />

<xs:element name="Name" type="xs:string" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:element>

</xs:choice>

</xs:complexType>

<xs:key name="DsPostKey1" msdata:PrimaryKey="true">

<xs:selector xpath=".//mstns:User" />

<xs:field xpath="mstns:ID" />

</xs:key>

</xs:element>

<xs:complexType name="PostType">

<xs:sequence>

<xs:element name="Body" type="xs:string" minOccurs="0" />

<xs:element name="UserID" type="xs:int" minOccurs="0" />

<xs:element name="Post" type="PostType" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:schema>

[Oleg Ogurok]

Nevermind. Once I clicked OK and Submit again, it worked. I guess there is a
bug in VS.NET.

-Oleg.

"Oleg Ogurok" <ol**@ogurok.com.ihatespammers.ireallydo.co> wrote in message
news:10*************@corp.supernews.com...

Hi all,

I'm trying to create a simple XML structure for storing tree-stryle data
for a forum-like software, e.g. each post will have a body field, the ID
of the user who posted the message, and zero or more subposts(replies).
Thus it would allow for unlimited depth of subposts.

I also need a simple table to store UserID, Full Name, etc of the users
posting messages.

I've created a schema in VS.NET 2003 as follows. However, now I need to
add a relation between ID field of User table and UserID field of Post
table (one-to-many). If I try to add such relation, I get "Failed to add
data relation. Exception has been thrown by the target of an invocation."

Any help is greatly appreciated.

----------------------
<?xml version="1.0" encoding="utf-8" ?>

<xs:schema id="DsPost" targetNamespace="http://tempuri.org/DsPost.xsd"
elementFormDefault="qualified"

attributeFormDefault="qualified" xmlns="http://tempuri.org/DsPost.xsd"
xmlns:mstns="http://tempuri.org/DsPost.xsd"

xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">

<xs:element name="DsPost" msdata:IsDataSet="true">

<xs:complexType>

<xs:choice maxOccurs="unbounded">

<xs:element name="Post">

<xs:complexType>

<xs:sequence>

<xs:element name="Body" type="xs:string" minOccurs="0" />

<xs:element name="UserID" type="xs:int" minOccurs="0" />

<xs:element name="Post" type="PostType" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:element>

<xs:element name="User">

<xs:complexType>

<xs:sequence>

<xs:element name="ID" type="xs:int" minOccurs="0" />

<xs:element name="Name" type="xs:string" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:element>

</xs:choice>

</xs:complexType>

<xs:key name="DsPostKey1" msdata:PrimaryKey="true">

<xs:selector xpath=".//mstns:User" />

<xs:field xpath="mstns:ID" />

</xs:key>

</xs:element>

<xs:complexType name="PostType">

<xs:sequence>

<xs:element name="Body" type="xs:string" minOccurs="0" />

<xs:element name="UserID" type="xs:int" minOccurs="0" />

<xs:element name="Post" type="PostType" minOccurs="0" />

</xs:sequence>

</xs:complexType>

</xs:schema>