relation between tables

Question

0.00/5 (No votes)

See more:

SQL-Server-2005

, +

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(strconn);
        con.Open();
        SqlDataAdapter da1 = new SqlDataAdapter("select  *  from SERVICES", con);
        SqlDataAdapter da2 = new SqlDataAdapter("select  *  from SUB_SERVICES as sub,SERVICES as services where sub.VOY_SERVICES_SERVICE_ID = services.VOY_SERVICES_SERVICE_ID", con);
   DataSet ds2 = new DataSet();
        da1.Fill(ds2, "SERVICES");

        da2.Fill(ds2, " SUB_SERVICES");

ds.Relations.Add("servicessel", ds.Tables["SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"], ds.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]);
      ds.Relations[0].Nested = true;
        ds.Relations.Add(subservices, ds.Tables["SUB_SERVICES"].Columns["VOY_SUB_SERVICES_SERVICE_ID"], ds.Tables["SUB_SERVICES_CATEGORIES"].Columns["VOY_SUB_SERVICES_SERVICE_ID"]);
        ds.Relations[1].Nested = true;
 services_repeater.DataSource = ds2;
        services_repeater.DataBind();
con.Close();

in

C#

ds.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]

its showing an error "Object reference not set to an instance of an object", please help me to over come this problem asap.

Posted 18-Jun-12 0:07am

shabadiveda

Updated 18-Jun-12 0:10am

Prasad_Kulkarni

v2

Add a Solution

Comments

shabadiveda 18-Jun-12 7:46am

thanx for the reply..,i changed ds to ds2, but still am getting the same error.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sandeep Mewara · Answer 1 · 2012-06-18T05:01:00

Object reference not set to an instance of an object

This error happens when you try to use a property or call a method of an object that is null. More details: here[^]

A simple use of Visual studio DEBUGGER can tell you the object because of which it is happening. Just look at the stack trace and put a debugger on that line. Check the objects of that line and see if any one is null and you are trying to use that objects property. Handle the same.

Based on what you say:

C#

ds.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"]

This means either ds is null or ds.Tables["SUB_SERVICES"] is null or ds.Tables["SUB_SERVICES"].Columns["VOY_SERVICES_SERVICE_ID"] is null. If you have data, check for table name typo or column name typo.

*Suvabrata Roy* · Answer 2 · 2012-06-18T00:28:00

Solution 1

Hi shabadiveda,

You have added Both of your Datatable at ds2and Build relation On ds.

I think you have done a silly mistake of typing wrong variable name or mix up with other variable name.

Posted 18-Jun-12 0:28am

Suvabrata Roy