oracle 得到 所有表

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.OracleClient;
using System.Collections;

namespace WindowsApplication1
{
public partial class Form1 : Form
{
ArrayList tables = new ArrayList();

public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{

//"Driver={Microsoft ODBC for Oracle};Server=OracleServer.world;Uid=Username;Pwd=asdasd;"
string ConnectionString = "user id=nqsystem;data source=orc1_24;password=nqsystem";
OracleConnection conn = new OracleConnection(ConnectionString);
try
{
conn.Open();
OracleCommand cmd = conn.CreateCommand();
cmd.CommandText = "select * from user_tables";
OracleDataReader odr = cmd.ExecuteReader();

while (odr.Read())
{
tables.Add(odr.GetString(0));
}
odr.Close();
}
catch (Exception ee)
{
MessageBox.Show(ee.Message);
}
finally
{
conn.Close();
}
foreach(string table in tables)
{
conn.Open();
OracleCommand cmd = conn.CreateCommand();
cmd.CommandText = "delete from " + table;
cmd.ExecuteNonQuery();
odr.Close();
}

}
}
}