The cursor type of the Recordset object affects whether the number of records can be determined. The RecordCount property will return -1 for a forward-only cursor; the actual count for a static or keyset cursor; and either -1 or the actual count for a dynamic cursor, depending on the data source.
动态集根据数据源,或者返回-1或者返回实际数目吗;forward-only 返回-1;static or keyset 返回实际数目