You can use Sybase Central to create a domain or assign it to a column.
Select the Domains folder.
Choose File > New > Domain.
The Create Domain wizard appears.
Follow the instructions in the wizard.
All domains appear in the Domains folder in Sybase Central.
For the desired table, click the Columns tab in the right pane.
In the data type column for the desired column do one of the following:
Choose the domain from the dropdown list.
Click the button beside the dropdown list and choose the domain on the property sheet.