Re: EOModel and derived column.
Re: EOModel and derived column.
- Subject: Re: EOModel and derived column.
- From: John Larson <email@hidden>
- Date: Wed, 24 Nov 2010 06:20:55 -0600
A note about those columns, they are only evaluated during fetch since their content is generated in the SQL. So if your user updates their last name, the full name won't update until the changes are committed and then fetched again.
Just a head's up.
John
Sent from my iPhone
On Nov 24, 2010, at 1:37 AM, Theodore Petrosky <email@hidden> wrote:
> I am reading the Red Webobject 5.0 book and I think I finally understand the small section on creating an attribute the is derived.
>
> (I am using postgresql as the backend)
>
> so my User entity has a firstName and a lastName. I created an attribute called 'theFullName' as derived "firstName || ' ' || lastName", in the advanced tab, I choose "Read Only".
>
> i assumed that would be enough, however I needed to also select 'allows null' in the basic tab. if I didn't, User.createUser(yada, yada); required a 'theFullName' attribute.
>
> My assumption was that as the column is derived and read only, I thought the column was special and shouldn't need the 'allows null' selection.
>
> so, did I do it correctly?
> as the column is a derived column and read only, why do I need to add 'allows null'?
>
> I have been creating all these derivatives in java in my User.java file, but I thought I would expand my understanding and play with some features.
>
> now on to stored proceedures.
>
> Ted
>
>
>
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