CODEWITHSUNDEEP
c#asp.netpostgresqlconnection-string
fishy101
fishy101

Reputation: 31

connect to tableau postgresql in C#

I want to connect to the tableau PostgreSQL server from my .Net framework to list all the reports and datasources published in the tableau server.

For doing this, I have done the following steps.

  1. Added the npgsql.dll reference that i downloaded online

  2. Added the below two namespaces in my class file

    using NpgsqlTypes; using Npgsql;

  3. I added the connection sting as follows

I also tried with modifying the connection string with port value and renaming the DataSource to Server, Initial catalog to Database and provider Name to Npgsqll

  1. My Method is as follows:

    public DataTable  getAllDataSourceNames()
{
    DataTable dataSourceNames = new DataTable();
    NpgsqlConnection conServer = new NpgsqlConnection(conString);
    conServer.Open();
    string command = @"select * from datasources";
    NpgsqlDataAdapter sqlcmd = new NpgsqlDataAdapter(command,conServer);
    sqlcmd.Fill(dataSourceNames);
    return dataSourceNames;
}`

  2. No error. I can build and run successfully the other links in the website. But cannot cannot establish connection to my postgresql server.

Any idea of how to establish the connection?

Upvotes: 1

Views: 663

Answers (2)

Hambone
Hambone

Reputation: 16407

Short answer -- no, not sure what's wrong. Your code doesn't raise any alarm bells.

Somewhat related, and it may help: I'm a big fan of the Connection StringBuilder with Npgsql. Here is a brief example:

NpgsqlConnectionStringBuilder sb = new NpgsqlConnectionStringBuilder();
sb.ApplicationName = "Tableau " + Environment.GetEvironmentVariable("USERNAME");
sb.Host = "1.2.3.4";
sb.Port = 5432;
sb.Username = "foo";
sb.Password = "bar";
sb.Database = "postgres";
sb.Pooling = false;
sb.Timeout = 120;

conServer = new NpgsqlConnection(sb.ToString());

It demistifies all of this and makes injecting parameters easy. I highly recommend you add the ApplicationName property so that when you are monitoring sessions, you will know who is who.

Upvotes: 0

Vijunav Vastivch
Vijunav Vastivch

Reputation: 4211

Working with Postgres Connection in c#:

private DataSet ds = new DataSet();
private DataTable dt = new DataTable();
public Form1()
{    
    InitializeComponent();    
}
private void llOpenConnAndSelect_LinkClicked(object sender, 
            LinkLabelLinkClickedEventArgs e)
{
    try
    {
        // PostgeSQL-style connection string
        string connstring = String.Format("Server={0};Port={1};" + 
            "User Id={2};Password={3};Database={4};",
            tbHost.Text, tbPort.Text, tbUser.Text, 
            tbPass.Text, tbDataBaseName.Text );
        // Making connection with Npgsql provider
        NpgsqlConnection conn = new NpgsqlConnection(connstring);
        conn.Open();
        // quite complex sql statement
        string sql = "SELECT * FROM simple_table";
        // data adapter making request from our connection
        NpgsqlDataAdapter da = new NpgsqlDataAdapter(sql, conn);
        // i always reset DataSet before i do
        // something with it.... i don't know why :-)
        ds.Reset();
        // filling DataSet with result from NpgsqlDataAdapter
        da.Fill(ds);
        // since it C# DataSet can handle multiple tables, we will select first
        dt = ds.Tables[0];
        // connect grid to DataTable
        dataGridView1.DataSource = dt;
        // since we only showing the result we don't need connection anymore
        conn.Close();
    }
    catch (Exception msg)
    {
        // something went wrong, and you wanna know why
        MessageBox.Show(msg.ToString());
        throw;
    }
}

The following link may help you: Using PostgreSQL in your C# .NET application

Upvotes: 1

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