Column Properties

To view or edit a column's properties, double-click its Browser or list entry. The property sheet tabs and fields listed here are those available by default, before any customization of the interface by you or an administrator.

The General tab contains the following properties:

Property

Description

Name/Code/Comment

Identify the object. The name should clearly convey the object's purpose to non-technical users, while the code, which is used for generating code or scripts, may be abbreviated, and should not normally include spaces. You can optionally add a comment to provide more detailed information about the object. By default the code is generated from the name by applying the naming conventions specified in the model options. To decouple name-code synchronization, click to release the = button to the right of the Code field.

Stereotype

Extends the semantics of the object. You can enter a stereotype directly in this field, or add stereotypes to the list by specifying them in an extension file.

Table

Specifies the table which contains the column.

Data type/ Length/ Precision

Specifies the form of data to be stored, such as numeric, alphanumeric, or Boolean, and, where appropriate, the maximum number of characters or numerals that can be stored, and the maximum number of places after the decimal point. Click the ellipsis button to choose from the list of standard data types (see PowerDesigner Standard Data Types).

To review the data types permitted by your DBMS, select Database > Edit Current DBMS and navigate to Script > DataType > PhysDataType). The following variables specify length and precision requirements:
  • %n - length
  • %s - length with precision
  • %p - decimal precision
For example, the data type char(%n) , requires you to specify a length.

Domain

Specifies the domain associated with the object (see Domains (CDM/LDM/PDM)). Use the tools to the right of this field to create or browse to a domain, or to open the property sheet of the selected domain.

Primary key

Specifies that the values in the column uniquely identify table rows (see Creating Primary Keys).

Foreign key

Specifies that the column depends on and migrates from a primary key column in another table (see Creating Foreign Keys).

Sequence

[if supported by your DBMS] Specifies the sequence associated with the column (see Sequences (PDM)).

Displayed

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

With default

[if supported by your DBMS] Specifies that the column must be assigned a value that is not null.

Mandatory

[if supported by your DBMS] Specifies that a non-null value must be assigned.

Identity

[if supported by your DBMS] Specifies that the column is populated with values generated by the database. Identity columns are often used as primary keys.

Computed

[if supported by your DBMS] Specifies that the column is computed from an expression using values from other columns in the table (see Creating a Computed Column).

Keywords

Provide a way of loosely grouping objects through tagging. To enter multiple keywords, separate them with commas.

Detail Tab

The Detail tab contain the following properties:

Property

Description

Column fill parameters
The fields in this groupbox model the size and distinctness of data values that you expect to store in the column and are used in conjunction with test data profiles (see Populating Columns with Test Data). You can specify:
  • Null values - [Default: 0%] Specifies the percentage of values to leave empty.
  • Distinct values - [Default: 100%] Specifies the percentage of values that must be unique
  • Average Length - [read only] Used for estimating the size of the database (see Estimating Database Size). The default value is the maximum length for the data type defined for the column.
You can enter values by hand or obtain them from your database by selecting the Statistics option in the Reverse Engineering dialog (see Reverse Engineering from a Live Database).

To refresh the values in these fields for all a table's columns at any time, right-click the table symbol or its entry in the Browser and select Update Statistics. To update the column statistics for all the tables in a model, select Tools > Update Statistics (see Reverse Engineering Database Statistics).

Profile

Specifies a test data profile to use to generate test data (see Populating Columns with Test Data). Use the tools to the right of this field to create or browse to a profile, or to open the property sheet of the selected profile.

Computed Expression

Specifies an expression used to compute data for the column (see Creating a Computed Column).
The following tabs are also available:
Parent topic: Columns (PDM)