You can reverse engineer statistics for an existing database, such as the number of distinct or null values in a column or the average length of a character field. These can provide helpful information when optimizing a design.
You can reverse engineer the statistics as part of the general reverse engineering process by selecting the Statistics checkbox in the Database Reverse Engineering window (see Reverse Engineering from a Live Database), or update them at any other time, using the dedicated Update Statistics window.
- Select to open the Update Statistics window (if PowerDesigner is not presently connected to a database via a live database connection, you will be required to connect):
- On the General tab, select or clear the checkboxes to specify whether you want to update statistics for tables and/or columns.
- [optional] Click the Selection tab and select or clear checkboxes to specify for which tables you want to update statistics:
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Click OK to begin the update. Progress appears in the Output window. For large updates, a progress dialog box opens, allowing you to cancel the update at any time.
When the process is complete, you can view the updated statistics in the property sheets of your tables and columns.
