C# connection à une bdd oracle

using System;
using System.Runtime.InteropServices;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Serialization;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
using System.Data;
using System.Data.OracleClient;
using System.Web;
using System.Collections;




namespace WebPart4
{

    
    [Guid("0781047e-d071-48d9-9ce7-463997e752ab")]
    public class WebPart4 : System.Web.UI.WebControls.WebParts.WebPart
    {
       
        public WebPart4()
        {
            this.ExportMode = WebPartExportMode.All;
        }

        public DataSet SelectOracleSrvRows(DataSet dataset, string connection, string query)
        {
            
            connection = "Provider = msdaora; Data Source = CHAINE HOTE ?; User Id = USER; Password = MDP;";
            query = "select * from intranet_employe";
            
            OracleConnection conn = new OracleConnection(connection);
            

            OracleDataAdapter adapter = new OracleDataAdapter();
            adapter.SelectCommand = new OracleCommand(query, conn);
            
            
            adapter.Fill(dataset);
            return dataset;
           
          
        }



        DataSet dataset = null;
        string valeur = null;
        string connection = null;
        string query = null;


        protected override void CreateChildControls()
        {
             
            this.Controls.Clear();
            TreeView tree = new TreeView();
            this.Controls.Add(tree);

            TreeNode rootNode = new TreeNode("AQUITANIS");
            TreeNode firstNode = new TreeNode("Direction Générale");
            TreeNode secondNode = new TreeNode("Direction des ressources Humaines");
            TreeNode thirdNode = new TreeNode("Direction Financière");
            TreeNode fourthNode = new TreeNode("Direction de la Location");
            TreeNode fifthNode = new TreeNode("Direction du Patrimoine");

            tree.Nodes.Add(rootNode);
            rootNode.ChildNodes.Add(firstNode);
            rootNode.ChildNodes.Add(secondNode);
            rootNode.ChildNodes.Add(thirdNode);
            rootNode.ChildNodes.Add(fourthNode);
            rootNode.ChildNodes.Add(fifthNode);

            
            rootNode.SelectAction = TreeNodeSelectAction.None;
            firstNode.SelectAction = TreeNodeSelectAction.None;
            secondNode.SelectAction = TreeNodeSelectAction.None;
            thirdNode.SelectAction = TreeNodeSelectAction.None;
            fourthNode.SelectAction = TreeNodeSelectAction.None;
            fifthNode.SelectAction = TreeNodeSelectAction.None;



            DataSet ds = SelectOracleSrvRows(dataset, connection, query);


            foreach (DataRow dr in ds.Tables[0].Rows)
            {

                // Remplace "nom_colonne" par le nom d'une des colonnes de ta table ORACLE 

                valeur = dr["nom"] as string;

                this.Page.Response.Write(valeur);


            }

        
        }
       


        
       


    }
    

}