C#之 oracle查询 得到DataSet数据

using Oracle.ManagedDataAccess.Client;

public static DataSet QuerySQL(string sqlString)
        {
            string connectionString = $"Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=your IP)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=you service)));User Id=your username;Password=your pwd;";
            using (OracleConnection connection = new OracleConnection(connectionString))
            {
                OracleCommand cmd = new OracleCommand();
                cmd.Connection = connection;
                try
                {
                    connection.Open();

                    OracleDataAdapter _oraAdp = new OracleDataAdapter(sqlString, cmd.Connection);
                    DataSet _ds = new DataSet();
                    _oraAdp.Fill(_ds);

                    if (!(_ds != null && _ds.Tables.Count > 0))
                        _ds = null;
                    //将Int16字段类型变更为Int32
                    if (_ds != null)
                    {
                        DataSet dsClone = new DataSet();
                        foreach (DataTable dt in _ds.Tables)
                        {
                            DataTable dtClone = dt.Clone();
                            foreach (DataColumn dc in dtClone.Columns)
                                if (dc.DataType == typeof(short) || dc.DataType == typeof(long))
                                    dc.DataType = typeof(int);
                            foreach (DataRow dr in dt.Rows)
                                dtClone.ImportRow(dr);
                            dsClone.Tables.Add(dtClone);
                        }
                        _ds = dsClone;
                    }
                    return _ds;

                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }