How can I create a UDP where the values can only be selected values from a predefined list? I do not want users to add any value, but pick up from a selected list of values?
For UDP (User Defined Property) List type, you create the UDP, by clicking Model -> User Defined Properties.
Choose the Class of the object of the UDP you want, like Entity, Table, Attribute, Column, etc. Please note that Logical UDPs are available at logical level only; e.g. an Entity level UDP is good for an Entity and not for a Table (physical side).
Create a new UDP by clicking the New Button and choose List for Type. The following UDP is for Model at the logical side:
Then in Default add in the List of values allowed, separated by comma. That will enforce the allowed values for the UDPs.
For example, when you click the Model Editor, you will have a UDP Tab and see the UDP you created. There you will see the list of available values as defined in the UDP to choose from in the list.
If you like to have a Null option as well, you can also add a space as a value, e.g. instead of "1, 2, 3" as shown above, you can add " ,1, 2, 3" which will show the UDP value as a blank by default when seen at the object level, but you can also drop down to pick from available values.