Toad World® Forums

using domain


#1

Hi All. just trying to understand DOMAINS in TDM.

i have a lot of tables which may have the same datatype col in many tables (they actually would have the same name and the same comment too…but domains doesn’t seem to control that).

anyway, as i understand it, if i set them to use a domain (instead of specifying a dataype)…if i were to realize that i had to modify them (say from varchar2(128) to varchar2(256))…they would all be modified at once?

(oh also, defaults and check constraints can be maintained there for the entire domain “group” too).

is that correct?

thanks, David Soniat - University of South Florida.


#2

Hi,

Yes, you understand the domains correctly.

If you use the same data type for many attributes, you can create a domain with the data type (including a default) and assign the domain to the attributes.
If you need to change the data type or default then, you will do it only once - in the domain. The change will be applied in all attributes with this domain then. So, it’s a great time saver.

Notes in domains are not applied in attributes as you can have a note to a domain and a different note to attribute.

Regards,

Vladka + TDM Team