primary forgien key error

Question

i have created two database tables.
1.town(town id as pk,town name)
2. phase(phase id,town id, phase name. phase id and town id are composite keys)

then i created a web form consists o textbox named as phase id, dropdown name as townid that takes town id from table 1, and textbox named as phase name. textbx 1 i enter phase id, select town from drop drown and enter the phase name. when i click on submit i give me the follwoing error

Exception Details: System.Data.SqlClient.SqlException: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Phase_Town". The conflict occurred in database "pda_rtc", table "dbo.Town", column 'TownID'.
The statement has been terminated.
how do i solve this problem????

Suthish Nair · Answer

put a breakpoint and check what value you are posting to DB table..

saifullah khan · Answer

yes value exists.

Suthish Nair · Answer

Are you sure the TownName.SelectedValue exists in your Town Table?

Praneeth Kumar · Answer

I have tried the same by creating a POC with database and it worked for me without any problem. Kindly compare your code with the one below and see what you are missing. I feel somewhere the TownId field is getting incremented and that value is being picked while inserting into database. aspx DataValueField=TownId Height=19px Width=121px AutoPostBack=True> --Select--  SelectCommand=SELECT * FROM [Town]> aspx.cs public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender EventArgs e) { } protected void Button1_Click(object sender EventArgs e) { SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings[2].ConnectionString); conn.Open(); SqlCommand cmd = new SqlCommand(insert into Phase values(4'Phase'' + TownName.SelectedValue + ')conn); cmd.ExecuteNonQuery(); conn.Close(); } }

saifullah khan · Answer

1.aspx Town Name DataSourceID=SqlDataSource2 DataTextField=TownID DataValueField=TownID Height=19px Width=121px AutoPostBack=True > --Select-- ConnectionString=  SelectCommand=SELECT * FROM [Town]> 1.aspx.cs con.Open(); cmd = new SqlCommand(insert into Phase values('+PhaseID.Text+'' + PhaseName.Text + '' + TownName.SelectedValue + ') con); cmd.ExecuteNonQuery();

Praneeth Kumar · Answer

Please share the code on how you bind the dropdownlist and how you get the selected value of dropdown list. If possible can you generate the queries of table Town and table Phase?

saifullah khan · Answer

sir now i used townid and stored it in the phase table but it is still giving same error. let me remind you once again that town id is used in phase table as a composite key with phaseid in the phase table

Muralidharan Deenathayalan · Answer

If you want to store the TownName in Phase table then you're not using the foreign key references. So it is better to store town id in the phase instead of storing town name in phase table. From the dropdownlist you can get the SelectedItem value which will have the townid .Pass this townid to the phase table to store.

saifullah khan · Answer

sir in town table there are two cols townid and town name where townid is the primary key. and in the second table that is phase table townid is used as the composite key. but i want to save the town name in phase table through drop down instead of town id

Praneeth Kumar · Answer

Guessing the logic I can guess wrong townid is being passed to insert phase query. The wrong townid is picked from the dropdownlist. This means the dropdownlist town id could be incremented by 1 so it could be like you are selecting the last item of the dropdown and inserting into phase table.

saifullah khan · Answer

yes townId is present in the town table i want to pass the townname to the database from dropdown(but remember the composite key is town id).

Muralidharan Deenathayalan · Answer

Does the TownID is present in the Town table? Are you passing the TownID or the TownName (from Dropdown) to the database ? if possible please post the code.