try
{

       DataSet dataSet = new DataSet();
       string connstr = "provider=MSDAORA.1;User ID=scott;Data
                        Source=<server>/<database>;Password=tiger;";
       string query = "SELECT * FROM USER_TAB_COLUMNS WHERE
                       TABLE_NAME='CUSTOMER'";

       using (OleDbConnection connection = new OleDbConnection(connstr))
       {

              connection.Open();

              using (OleDbDataAdapter adapter = new OleDbDataAdapter(query,
                                                        connection))
              {
                        adapter.Fill(dataSet, "CUSTOMER");
              }

       }

       if (dataSet.Tables[0].Rows.Count > 0)
       {
             Trace.Write("Table exists in database");
       }
       else
       {
             Trace.Write("Table does not exists in database");
       }

}
catch (Exception ex)
{
       throw ex;
}