In what order C# execute sqlstatement? - ado.net

Question

I have two table related by foreign and primary key constraint.The Visit_Number in Patient table must exist in the Visit table.In my code in define create two instance of my connection string such that i can use one instance to insert record:VisitNumber in Visit table first and then the other instance to insert record in the patient table,with the believe that the cord runs from top to bottom.But this was n't the case. i still get foreign key constraint errror:
Error Number:547
Error MessageThe INSERT statement conflicted with the FOREIGN KEY constraint "Patient_Vist_FK".
The conflict occurred in database "TestDB", table "dbo.Visit", column 'Visit_Number'.
The statement has been terminated.On line Number: 1
meaning the code is running as i expected. Please do you have a better approach and why isn't mine working
code:
protected void btn_save_Click(object sender, EventArgs e)
{
string connect = System.Configuration.ConfigurationManager.ConnectionStrings["db_connection"].ToString();
SqlConnection con = new SqlConnection(connect);
SqlConnection con2 = new SqlConnection(connect);
string visitnumber = txtVistNumber.Text.ToString();
string insert_statement = "Insert into Patient(Patient_Number,FirstName,LastName,Gender,Tribe,Date_Of_Birth,Visit_Number)"
+ "Values(#Patient_Number,#FirstName,#LastName,#Gender,#Tribe,#Date_Of_Birth,#Visit_Number)";
string insert_stament2 = "Insert into Visit(Visit_Number)"
+ "Values(#Visit_Number)";
SqlCommand cmd = new SqlCommand(insert_statement, con);
SqlCommand cmd2 = new SqlCommand(insert_stament2, con2);
cmd2.Parameters.AddWithValue("#Visit_Number", txtVistNumber.Text);
cmd.Parameters.AddWithValue("#Patient_Number",txtpatientNum.Text);
cmd.Parameters.AddWithValue("#FirstName",txtfirstName.Text);
cmd.Parameters.AddWithValue("#LastName",txtlastname.Text);
cmd.Parameters.AddWithValue("#Gender", drl_gender.SelectedValue);
cmd.Parameters.AddWithValue("#Tribe",DropDownList1.Text);
cmd.Parameters.AddWithValue("#Date_Of_Birth", val_age.Text);
cmd.Parameters.AddWithValue("#Visit_Number", txtVistNumber.Text);
try
{
using (con)
{
con.Open();
int count = cmd.ExecuteNonQuery();
if (count > 0)
{
Response.Write("<script language=javascript>alert('Record Sucessfully Inserted!');</script>");
//Success_Message.Text = "Record inserted";
txtpatientNum.Text = String.Empty;
txtfirstName.Text = String.Empty;
txtlastname.Text = String.Empty;
txtVistNumber.Text = String.Empty;
DropDownList1.Text = String.Empty;
val_age.Text = String.Empty;
}
}
}
catch (SqlException ex)
{
{
VisitError_Message.Text = "Error Number:" + ex.Number.ToString() + " Error Message" + ex.Message + "On line Number" + ": " + ex.LineNumber;
}
}
catch (NullReferenceException nullexception)
{
VisitError_Message.Text = "Error Occurred, Error Type:" + nullexception.GetType().ToString() + "Error Message:" + nullexception.Message;
}
catch (DllNotFoundException dllexception)
{
VisitError_Message.Text = dllexception.GetType().ToString() + dllexception.Message;
}
finally
{
con.Close();
}
}

Answer 1

you not excuting you cmd2, you must execute the insert Visit_Number in cmd2 then excute your cmd, you can test this code
using (con2)
{
con2.Open();
cmd2.ExecuteNonQuery();
}
then you can excute your cmd
using (con)
{
con.Open();
int count = cmd.ExecuteNonQuery();
}
and you can do the work with the same connexion if you want
string connect = System.Configuration.ConfigurationManager.ConnectionStrings["db_connection"].ToString();
SqlConnection con = new SqlConnection(connect);
string visitnumber = txtVistNumber.Text.ToString();
string insert_statement = "Insert into Patient(Patient_Number,FirstName,LastName,Gender,Tribe,Date_Of_Birth,Visit_Number)"
+ "Values(#Patient_Number,#FirstName,#LastName,#Gender,#Tribe,#Date_Of_Birth,#Visit_Number)";
string insert_stament2 = "Insert into Visit(Visit_Number)"
+ "Values(#Visit_Number)";
using(con)
{
con.open;
SqlCommand cmd2 = new SqlCommand(insert_stament2, con);
cmd2.Parameters.AddWithValue("#Visit_Number", txtVistNumber.Text);
cmd2.ExecuteNonQuery();
SqlCommand cmd = new SqlCommand(insert_statement, con);
cmd.Parameters.AddWithValue("#Visit_Number", txtVistNumber.Text);
cmd.Parameters.AddWithValue("#Patient_Number",txtpatientNum.Text);
cmd.Parameters.AddWithValue("#FirstName",txtfirstName.Text);
cmd.Parameters.AddWithValue("#LastName",txtlastname.Text);
cmd.Parameters.AddWithValue("#Gender", drl_gender.SelectedValue);
cmd.Parameters.AddWithValue("#Tribe",DropDownList1.Text);
cmd.Parameters.AddWithValue("#Date_Of_Birth", val_age.Text);
cmd.Parameters.AddWithValue("#Visit_Number", txtVistNumber.Text);
cmd.ExecuteNonQuery();
}