Column Properties

Name

Specifies the name of the item, which should be clear and meaningful, and should convey the item's purpose to non-technical users.

Code

Specifies the technical name of the object, which is used for generating code or scripts, which may be abbreviated, and should not generally include spaces.

Comment

Specifies a descriptive label for the column.

Stereotype

Sub-classification used to extend the semantics of an object without changing its structure; it can be predefined or user-defined.

Table

Specifies the table which contains the column.

Data type

Specifies the form of data stored in the column, such as numeric, alphanumeric, boolean, or others.

Displayed

Specifies that the column can be displayed in the table symbol.

Length

Specifies the maximum length of data stored in the column.

Precision

Specifies the maximum number of places after the decimal point.

Identity

Specifies that the column is populated with values generated by the database. Identity column are often used as primary keys(not available for all DBMSs).

Domain

Specifies the name of the associated domain (see Domains (CDM/LDM/PDM)). Use the tools to the right of the list to create a domain, browse the tree of available domains, or view the properties of the currently selected domain.

Computed

Specifies that the column is computed from an expression using values from other columns in the table (not available for all DBMSs).

Primary key

Specifies that the values in the column uniquely identify table rows.

Foreign key

Specifies that the column depends on and migrates from a primary key column in another table.

Mandatory

Specifies that the column must be assigned a value that is not null.

With default

Specifies that a default value is assigned to the column when a null value is inserted (not available for all DBMSs).

Null Values

Specifies the proportion of column entries which contain null values. You can enter a number or percentage in this and the other fields in the Column fill parameters groupbox or obtain them from your database (see Obtaining Column Statistics from your Database).

Distinct Values

Specifies the proportion of column entries which contain distinct values. You can enter a number or percentage in this field or derive its value from database statistics. For example, if you set the percentage of distinct values to 100 % for one table column to 80% for a second column and then generate the table with 10 rows, all 10 rows in the first column will have distinct values, while only 8 rows in the second column will have distinct values.

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.

Profile

Specifies a test data profile to use to generate test data for the column. Click the ellipsis button to the right of this field to access the List of Test Data Profiles (see Populating Columns with Test Data).

Computed Expression

Specifies an expression used to compute data for the column (see Creating a Computed Column).