Create Database Table Columns

A database Table column is represented in the UML Data Modeling Profile as an attribute with the <<column>> stereotype. For a selected Table, you can review the existing columns and create new columns, on the Columns tab of the Columns and Constraints screen.

You can define column details directly on the list of columns on the Columns tab. The changes are automatically saved as you complete each field. Some fields have certain restrictions on the data you can enter, as described here. The tab also contains a Properties panel and a Notes field, which display the existing information on the selected column, and which you can edit. Each new column that you create is initially added as a row of default values at the end of the list.

Access     In diagram, right-click on required Table | Features & Properties | Attributes > Columns | Right-click | Add new column (Ctrl+N)

Create columns in a Table

Field/Option/Button

Action

See also

Name

Overtype the default name with the appropriate column name text.

 

 

Type

Click on the drop-down arrow and select the appropriate datatype for the column.

The available datatypes depend on the DBMS assigned to the parent Table.

 

 

Length

(Optional) Some datatypes have a length component - for example, VARCHAR has a length that defines the number of characters that can be stored. If the datatype does not have a length component, this field is disabled.

If the field is available and if you need to define a number of characters, type the value here.

 

 

Scale

(Optional) Some datatypes have a scale component - for example, DECIMAL has a scale that defines the number of  places of decimal that can be held. If the datatype does not have a scale component, this field is disabled.

If the field is available and if you need to define a scale, type the value here.

 

 

PK

Select the checkbox if the column is part of the Primary Key for this Table.

 

Create a Primary Key

Not Null

Select the checkbox if empty values are forbidden for this column.

The checkbox is disabled if the PK checkbox is selected.

 

 

Alias

If required for display and documentation purposes, type in an alternative name for the field.

 

 

Initial Value

If required, type in a value that can be used as a default value for this column.

 

 

Notes

Type in any additional information necessary to document the column.

You can format the text using the Notes toolbar at the top of the field.

Notes

Notes Toolbar

 

Column Properties

The appropriate properties for the Table's Database Management System automatically display in the Property panel (expand the Column (<name>) branch if they are not visible).

Property

DBMS

Notes

Autonum

(Startnum

Increment)

Oracle

MySQL

SQL Server

DB2

PostgreSQL

Sybase ASA

Sybase ASE

 

If you require an automatic numbering sequence, set this property to True and, if necessary, define the start number and increment.

Generated

DB2

Set this additional property for auto numbering in DB2, to By Default or Always.

 

NotForRep

SQLServer

Set this property to True if you want to block replication.

 

Zerofill

MySQL

 

Set this property to True or False to indicate if fields are zerofilled or not.

Unsigned

MySQL

 

Set this property to True or False to indicate if fields accept unsigned numbers.

LengthType

Oracle

 

Set this property to define the character semantics as None, Byte or Char.

Notes

·For MySQL, before creating Table columns you must first add ENUM and SET datatypes
 

Learn more

 

Learning Center topics

·(Alt+F1) | Enterprise Architect | Database Engineering | Physical Data Model | Add Column