Number Specifies the estimated number of records in the table in the physical database, which is used to estimate database size. This box is automatically populated during reverse engineering if you select the Statistics check box in the Reverse Engineering dialog box (see "Reverse Engineering from a Live Database" in the "Reverse Engineering a Database into a PDM" chapter). You can enter your own value in this field, or refresh its statistics (along with those for all of the table's columns) at any time by right-clicking the table symbol or its entry in the Browser and selecting Update Statistics from the contextual menu. You can also update the statistics for all tables by selecting Tools > Update Statistics (see "Reverse Engineering Database Statistics" in the "Reverse Engineering a Database into a PDM" chapter).
You can enter your own value in this field, or refresh its statistics (along with those for all of the table's columns) at any time by right-clicking the table symbol or its entry in the Browser and selecting Update Statistics from the contextual menu. You can also update the statistics for all tables by selecting Tools > Update Statistics (see "Reverse Engineering Database Statistics" in the "Reverse Engineering a Database into a PDM" chapter).
Number项是表的编号，用于统计表个数，一般在反向工程使用，看上面的帮助文本