C# - Using DataAdapter to Update SQL table from a DataTable - SQL table not updating [closed]

Question

I select * from an Excel spreadsheet into DataTable dt. I want to take those values and update the SQL table. The SQL table exists because of a manual import to SQL from the original Excel spreadsheet, has a primary key set. The user updates the excel sheet and I need to update the SQL values. I am setting the dt.RowState to modified in an effort to invoke the update. I get no error but the SQL table does not update. Previous test show my SQL permissions and connection is good, I can modify the table.

connectionToSQL = new SqlConnection(SQLConnString);
connectionToSQL.Open();
var cmd = new SqlCommand("SELECT * FROM TAGS$",connectionToSQL);                 
var da = new SqlDataAdapter(cmd);
var b = new SqlCommandBuilder(da);
foreach (DataRow r in dt.Rows)
{
    r.SetModified();
}
da.Update(dt);   

Answer 1

Try this:

using System.Data;
using System.Data.SqlClient;
using System;
namespace Q308507 {
    class Class1 
    {
        static void Main(string[] args) 
        {
            SqlConnection cn = new SqlConnection();
            DataSet CustomersDataSet = new DataSet();
            SqlDataAdapter da;
            SqlCommandBuilder cmdBuilder;
            // Set the connection string of the SqlConnection object
            // to connect to the SQL Server database in which you
            // created the sample table.
            cn.ConnectionString =
            "Server=server;Database=northwind;UID=login;PWD=password;";
            cn.Open();      
            // Initialize the SqlDataAdapter object by specifying a
            // Select command that retrieves data from the sample table.
            da = new SqlDataAdapter("select * from CustTest order by CustId", cn);
            // Initialize the SqlCommandBuilder object to automatically
            // generate and initialize the UpdateCommand,
            // InsertCommand, and DeleteCommand properties
            // of the SqlDataAdapter.
            cmdBuilder = new SqlCommandBuilder(da);
            // Populate the DataSet by running the Fill method
            // of the SqlDataAdapter.
            da.Fill(CustomersDataSet, "Customers");
            // Display the Update, Insert, and Delete commands
            // that were automatically generated
            // by the SqlCommandBuilder object.
            Console.WriteLine(
                "Update command Generated by the Command Builder : ");
            Console.WriteLine(
                "==================================================");
            Console.WriteLine(
                cmdBuilder.GetUpdateCommand().CommandText);
            Console.WriteLine("         ");
            Console.WriteLine(
                "Insert command Generated by the Command Builder : ");
            Console.WriteLine(
                "==================================================");
            Console.WriteLine(cmdBuilder.GetInsertCommand().CommandText);
            Console.WriteLine("         ");        
            Console.WriteLine(
                "Delete command Generated by the Command Builder : ");
            Console.WriteLine(
                "==================================================");
            Console.WriteLine(cmdBuilder.GetDeleteCommand().CommandText);
            Console.WriteLine("         ");
            // Write out the value in the CustName field before
            // updating the data using the DataSet.
            Console.WriteLine("Customer Name before Update : " +
                CustomersDataSet.Tables["Customers"].Rows[0]["CustName"]);
    
            // Modify the value of the CustName field.
            CustomersDataSet.Tables["Customers"].Rows[0]["CustName"] = "Jack";
            // Post the data modification to the database.
            da.Update(CustomersDataSet, "Customers");        
            Console.WriteLine("Customer Name updated successfully");
            // Close the database connection.
            cn.Close();
            // Pause
            Console.ReadLine();
        }
    }
}