C# Transfer Data from ODBC Database to Local SQL Database

Question

I have connected to a DB through an ODBC connection. The data is on a server and I have the appropriate permissions and username/password.

I am trying to import some of the data into a local SQL database (.mdf). I suspect my SQL statement is wrong.

The idea is that when a an item is selected from a listBox that the data will be downloaded to the SQL database. This has completely stopped any progress on my project. Please help!!!

    public partial class frmNorth : Form
    {
            // variables for the connections 
            private OdbcConnection epnConnection = new OdbcConnection();
            private SqlConnection tempDbConnection = new SqlConnection();
    public frmNorth()
    {
        InitializeComponent();
        // This is for the ePN DB
        epnConnection.ConnectionString = @"Dsn=ePN; uid=username; pwd=myPa$$Word";
        // This is for the local DB
        tempDbConnection.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\TempDB.mdf;Integrated Security=True";
    }
    private void lbxFSR_SelectedIndexChanged(object sender, EventArgs e)
    {
        try //For ePN
        {
            //This is where I need the help <--------------------
            epnConnection.Open();
            tempDbConnection.Open();
            OdbcCommand epnCommamd = new OdbcCommand();
            epnCommamd.Connection = epnConnection;
            string epnQuery =   "INSERT INTO " + tempDbConnection + ".tblTemp (FNCL_SPLIT_REC_ID, PROJ_ID, SALES_SRC_PRC) " +
                                "SELECT PROJ_FNCL_SPLIT.FNCL_SPLIT_REC_ID,PROJ_FNCL_SPLIT.PROJ_ID,PROJ_FNCL_SPLIT.SALES_SRC_PRC " + 
                                "FROM " + epnConnection + ".PROJ_FNCL_SPLIT " + 
                                "WHERE PROJ_ID=" + lbxFSR.Text + "";
            epnCommamd.CommandText = epnQuery;
            epnCommamd.CommandTimeout = 0;
            epnCommamd.ExecuteNonQuery();

            epnConnection.Close();
            tempDbConnection.Close();
        }
        catch (Exception ex)
        {
            epnConnection.Close();
            tempDbConnection.Close();
            MessageBox.Show("Error " + ex);
        }
    }
    }

This is the error that I get. The error occurs at epnCommamd.ExecuteNonQuery();

Picture of Error Message

Answer 1

I cant comment cause i don't have enough points so i have to put this in answers but do both of your connections actually open? I would also avoid showing passwords in your connection strings on here.

Answer 2

The problem is that you can't in general INSERT into one table using a SELECT from a table on another database in the way that you're attempting. If source and destination tables are on same database server (eg both on Sql Server) you have a shot at INSERT INTO db1.SourceTable ... SELECT ... FROM db2.DestinationTable .

However, since you have source table on ODBC connection and destination on Sql connection, this won't work.

You need to do it in two steps. Download your ODBC table into a C# DataTable , then upload the C# DataTable into your Sql Server table. I can't test against your databases, but I have tested a version of this code on transfers between Microsoft Access database and a Sql Server database

private void lbxFSR_SelectedIndexChanged(object sender, EventArgs e)
{
    try //For ePN
    {
        //This is where I need the help <--------------------

        // Break the operation into two parts
        // The ODBC & SQL databases can't talk directly to each other.

        // 1. Download ODBC table into your C# DataTable

        DataTable dt;
        epnConnection.Open();
        string epnQuery =   "SELECT FNCL_SPLIT_REC_ID, PROJ_ID, SALES_SRC_PRC " + 
                            "FROM PROJ_FNCL_SPLIT " + 
                            "WHERE PROJ_ID='" + lbxFSR.Text + "'";
        OdbcCommand epnCommamd = new OdbcCommand(epnQuery, epnConnection);
        epnCommamd.CommandTimeout = 0;
        OdbcDataReader dr = epnCommamd.ExecuteReader();
        dt.Load(dr);
        epnConnection.Close();

        // 2. Upload your C# DataTable to the SQL table

        // This select query tells the SqlDataAdapter what table you want to work with, on SQL database
        // The WHERE 0 = 1 clause is to stop it returning any rows, 
        // however you still get the column names & datatypes which you need to perform the update later
        string selectQuery = "SELECT FNCL_SPLIT_REC_ID, PROJ_ID, SALES_SRC_PRC " +
                            " FROM PROJ_FNCL_SPLIT WHERE 0 = 1";
        tempDbConnection.Open();
        var da = new SqlDataAdapter(selectQuery, tempDbConnection);
        var commandBuilder = new SqlCommandBuilder(da);
        // The DataAdapter's `Update` method applies the contents of the DataTable `dt` to the table specified in the `selectQuery`.
        // It does this via the SqlCommandBuilder, which knows how to apply updates to a Sql Database.
        da.Update(dt);                                      // Channel the C# DataTable through the DataAdapter
        tempDbConnection.Close();
    }
    catch (Exception ex)
    {
        epnConnection.Close();
        tempDbConnection.Close();
        MessageBox.Show("Error " + ex);
    }
}