relation between tables

Question

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SQL-Server-2005

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Hello,

I am having a dataset in which am having 2 tables,i want to build relation between them. my 2 tables are as listed below.

SQL

CREATE TABLE SERVICES
(VOY_SERVICES_SERVICE_ID INT PRIMARY KEY IDENTITY(1,1),
VOY_SERVICES_SERVICE_NAME VARCHAR(50))
 
CREATE TABLE SUB_SERVICES
(VOY_SUB_SERVICES_SERVICE_ID INT PRIMARY KEY IDENTITY(1,1),
VOY_SERVICES_SERVICE_ID INT FOREIGN KEY REFERENCES SERVICES (VOY_SERVICES_SERVICE_ID),
VOY_SUB_SERVICES_SERVICE_NAME VARCHAR(50))

i tried this code,

C#

 SqlConnection con = new SqlConnection( "Data Source=USER-PC\\SQLEXPRESS;Initial Catalog=VOY;Integrated Security=True");
        con.Open();
      
        SqlDataAdapter da = new SqlDataAdapter("select  *  from SERVICES;select  *  from SUB_SERVICES as sub,SERVICES as services where sub.VOY_SERVICES_SERVICE_ID = services.VOY_SERVICES_SERVICE_ID", con);

da.TableMappings.Add("Table";, "SERVICES");
       da.TableMappings.Add("Table1";, "SUB_SERVICES");

 DataSet ds2 = new DataSet();
        da.Fill(ds2);
ds2.Relations.Add(ds2.Tables["SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"],
          ds2.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]);
          ds2.Relations[0].Nested = true;
          ds2.Relations.Add("subservices", ds2.Tables[" SUB_SERVICES"].Columns["VOY_SUB_SERVICES_SERVICE_ID"], ds2.Tables["SUB_SERVICES_CATEGORIES "].Columns["VOY_SUB_SERVICES_SERVICE_ID"]);
          ds2.Relations[1].Nested = true;

C#

services_repeater.DataSource = ds2;
        services_repeater.DataBind();
        con.Close();

am getting the error as "Object reference not set to an instance of an object" at
ds2.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]) please help me. am using the repeaters so that i can get the chechboxes in nested format, and my .aspx page is as shown,

XML

<asp:Repeater id="services_repeater" runat="server" EnableViewState="false">
    <ItemTemplate>
    Services:<%#DataBinder.Eval(Container.DataItem,"VOY_SERVICES_SERVICE_ID") %> &nbsp;&nbsp;
    <%#DataBinder.Eval(Container.DataItem,"VOY_SERVICES_SERVICE_NAME") %>
    <br />
    <asp:Repeater runat="server" EnableViewState="false" DataSource='<%# GetChildRelation(Container.DataItem,"SERVICES") %>'>
    <ItemTemplate>
     &nbsp;&nbsp; &nbsp;&nbsp;
     SubserviceID:<b><%#DataBinder.Eval(Container.DataItem,"VOY_SUB_SERVICES_SERVICE_ID")%>  </b>
     <br />
     <asp:Repeater runat="server" EnableViewState="false" DataSource='<%#GetChildRelation (Container.DataItem,"SUB_SERVICES")%>'>
     <ItemTemplate>
       &nbsp;&nbsp; &nbsp;&nbsp;
         &nbsp;&nbsp; &nbsp;&nbsp;
         <b><%#DataBinder.Eval(Container.DataItem,"VOY_SUB_SERVICES_CATEGORIES_NAME") %></b>
     </ItemTemplate>
     </asp:Repeater>
    </ItemTemplate>
    </asp:Repeater>
    </ItemTemplate>
    </asp:Repeater>

any solution is welcome.

Posted 18-Jun-12 2:01am

shabadiveda

Updated 18-Jun-12 3:52am

Mohamed Mitwalli

v2

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Comments

Nilesh Patil Kolhapur 18-Jun-12 10:00am

user stored procedure instead of inline query

Sandeep Mewara 18-Jun-12 11:13am

Why repost?

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Rahul saraswat · Answer 1 · 2012-06-18T04:16:00

Hi, I think you r doing a mistake. I think your parent table is services. and your child table is Sub_Services. for making a relation on these two tables, u should use a common column od both tables i.e. VOY_SERVICES_SERVICE_ID.
but here u have used VOY_SUB_SERVICES_SERVICE_ID. so, i think you should add this line.....

ds2.Relations.Add("subServices", ds2.Tables["SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"], ds2.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]);

use it. I hope your problem will be resolved efficiently.

Thanks