Column Property Sheet Detail Tab

Null Values

Specifies the number (or percentage) of column entries which contain null values. You can enter a number or percentage in this field or derive its value from database statistics (see Updating Column Statistics).

Distinct Values

Specifies the number (or percentage) of column entries which contain distinct values. You can enter a number or percentage in this field or derive its value from database statistics (see Updating Column Statistics).

For example, you generate a table with 2 columns and 10 rows. You set the percentage of distinct values to 100 % for Column 1 and to 80% for Column 2. This implies that 10 rows will have distinct values in Column 1, and 8 rows in Column 2.

When you apply a test data profile with a list generation source to a column with a given percentage of distinct values, PowerDesigner uses the values from the test data profile list. If there are not enough values declared in the list, a warning message is displayed in the Output window to inform you that the distinct value parameter cannot be enforced due to lack of distinct values in the list of values.

Average Length

Specifies the average length of a value. You can enter a number in this field or derive its value from database statistics (see Updating Column Statistics).

Profile

Test data profile selected from the list. Profiles can use characters, numbers or date/time data types.

For more information, see Using Test Data.

Computed Expression

Computed expression typed directly in the Computed Expression pane or defined with the SQL Editor (accessed with the Edit tool) which helps you define more complex expressions.

For more information, see Creating a computed column.