Sql server if the row exist it update if the row new won't update

Question

I am
working with Asp.net and C# and using SQl Server, I insert a row in one plase and works fine but when I try to update the same row it woudn't do anything, I
try to update an existing row it works with the same code but not if I just
insert new row.
my code as
below:
String companyName = txCompany.Text.ToString();
SqlConnection con =
new
SqlConnection(conString);
SqlCommand cmd =
new
SqlCommand("INSERT
INTO DocUp (CompanyName)VALUES (@CompanyName)", con);
cmd.Parameters.AddWithValue("@CompanyName", companyName);
try
con.Open();
cmd.ExecuteNonQuery();
catch (Exception
er)
Response.Write("<script language='javascript'>alert('Connection Problem On Insert');</script>");
finally
con.Close();
string strQuery =
"UPDATE DocUp SET 
QuoteFileName=@QuoteFileName, ContentType=@ContentType, QuoteFileData=@Data WHERE CompanyName=@Company";
SqlCommand cmd =
new
SqlCommand(strQuery);
cmd.Parameters.Add("@QuoteFileName",
SqlDbType.VarChar).Value = filename;
cmd.Parameters.Add("@ContentType",
SqlDbType.VarChar).Value =
"application/pdf";
cmd.Parameters.Add("@Data",
SqlDbType.Binary).Value = bytes;
cmd.Parameters.Add("@Company",
SqlDbType.VarChar).Value = companyName;
InsertUpdateData(cmd);
private
Boolean InsertUpdateData(SqlCommand
cmd)
String strConnString = System.Configuration.ConfigurationManager
.ConnectionStrings["S7V001_11022014ConnectionString1"].ConnectionString;
  SqlConnection con =
new
SqlConnection(strConnString);
cmd.CommandType = CommandType.Text;
cmd.Connection = con;
try
con.Open();
cmd.ExecuteNonQuery();
return
true;
      catch (Exception
ex)
Response.Write(ex.Message);
return
false;
finally
con.Close();
con.Dispose();

Answer 1

Please use the  "Insert code block" button to insert *readable* code blocks 
try{
con.Open();
cmd.ExecuteNonQuery();
return true;
You have not shared what query/functions that you are using to insert data. Please share. 
Also it looks like more like a .Net related questions, (and if you agree,  ) I would recommend posting the question in .Net forum
http://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=csharpgeneral
Also I would recommend you to read "How to ask questions in Technical Forums" from the below link
Satheesh
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