I have connected my local database created by sql server with my project in visual studio (C#). Now I wish to enter the data given in the text field by the user in to my database. Here is what i have tried to do

```
    private void Button_AddCustomer_Click(object sender, EventArgs e)
    {
         try
         {
             //SqlConnection objsqlconn = new SqlConnection(conn);
             SqlConnection myConnection = new SqlConnection("Data Source=SHIRWANIPC;" + 
"Initial Catalog=TEST DATABASE;" + "Integrated Security=True");
             myConnection.Open();
             SqlCommand objcmd = new SqlCommand("INSERT INTO 
Customer(PhoneNumber,MobileNumber,Address) VALUES (a, b, c)", myConnection);
             objcmd.ExecuteNonQuery();
         }
         catch(SqlException ex)
         {
              MessageBox.Show(ex.ToString());
         }
     }

```

It throws an exception saying that `invalid column name a,invalid column name b,invalid column name c`. Whats the problem and how do I get input from the user into my database using insert query ? I am working on visual studio C# and the local database was created by using ms sql.