Re: pulling data from 2 tables
Re: pulling data from 2 tables
- Subject: Re: pulling data from 2 tables
- From: "Jerry W. Walker" <email@hidden>
- Date: Fri, 17 Feb 2006 08:12:14 -0500
On Feb 17, 2006, at 7:20 AM, Ken Anderson wrote:
You guys are like a married couple! No one would believe you live
on opposite sides of the US! :)
Heh, you've heard of Click and Clack, the Tappet Brothers? Just think
of us as Revert and Reset, the Stack Brothers.
Personally, I haven't yet gotten over cyber communities that let me
chat daily, request and offer help to WO folk from Austria to
Australia (They're both near Sydney, aren't they? Oops, Mozart was
from Salzburg, so they must be suburbs of Vienna).
On Feb 17, 2006, at 12:00 AM, Jerry W. Walker wrote:
Hi, Jim & Chuck,
On Feb 16, 2006, at 9:11 PM, Chuck Hill wrote:
Hi Jim,
On Feb 16, 2006, at 5:36 PM, Jim Wong wrote:
oh... i have an entity COMPANY which has an attribute
customerIndustryID which stores for exception numbers like 7,
10, 11 etc. this numbers can be found in another entity INDUSTRY
which has a corresponding attribute like F&B (7), Banking (10),
Manufacturing (11) etc.
Now where is that Jerry Walker? He loves questions like this...
He was at choir practice rehearsing Mozart's Requiem. Wonderful
music and the right year to do it. :-)
...and you got some nerve, asking that, after traipsing around the
world for a month and making the rest of us work as hard as you do
answering these questions while you were gone!
OK, I will do a short version and Jerry can do the epic later.
I'm not sure there's any need for an epic here, if I understand
Jim's question correctly.
A fundamental rule of thumb with WO (and EOF in particular) is
"If you are thinking about keys, you are doing it wrong". Let
EOF worry about the numbers. You worry about objects.
What does your model look like? You should have a Company entity
related (the a to-one relationship) to an Industry entity based
on company.customer_industry_id = industry.industry_id or
whatever you called the columns in the database. If not, you
should go back and read the tutorials and documention on
EOModeler and consider them in the context of what you are trying
to do.
Heh, yeah, what Chuck said.
How do I display all the information of a COMPANY in a form and
when it display customerIndustryID, i want it to display the
name like F&B, Banking, Manufacturing instead of the numbers
stored in the COMPANY?
First off, customerIndustryID should not be a class attribute so
you should not even have the option of showing it. :-) Exposed
keys Bad. Marking the primary and foreign keys as not class
properties (click the diamond to the left in EOModeler) can help
prevent many problems when you are starting out.
This is where I got a bit confused. If the Industry number is a
number assigned by some authoritative outside agency (say, a
government taxing agency or some such) and is meaningful to the
users of Jim's system as such, then it should probably be a class
attribute but it should NOT be used as a primary key for the
industry table or as a foreign key for the company table.
On the other hand, if it is simply an arbitrary (unique for each
industry) number that Jim made up, or that was assigned by his
DBMS, then Chuck is absolutely right, it is a primary key to the
INDUSTRY table, can be used as a foreign key in the COMPANY table,
it is an artifact of database technology and should not be carried
over, or show up at all, in Jim's object graph (that is, it should
not be a class property as Chuck mentioned).
So, Jim, if you were including the keys from the database in your
object graph, you're resisting the "Way of WO" and you're welcome
to request my epic answer. If not, then Chuck's answer (with no
admonitions) probably suffices.
Now, if your model is correct, all you need to do is to call
customer().industry().name() to get F&B, Banking etc. For use in
WO page, add a WOString and bind it to customer.industry.name.
Yes, it really is that simple when you are using WO!
Absolutely! I couldn't have said it better myself... I could
have said it in way more words, but not better. :-)
Regards,
Jerry
--
__ Jerry W. Walker,
WebObjects Developer/Instructor for High Performance Industrial
Strength Internet Enabled Systems
email@hidden
203 278-4085 office
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--
__ Jerry W. Walker,
WebObjects Developer/Instructor for High Performance Industrial
Strength Internet Enabled Systems
email@hidden
203 278-4085 office
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
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