Re: pulling data from 2 tables
Re: pulling data from 2 tables
- Subject: Re: pulling data from 2 tables
- From: Chuck Hill <email@hidden>
- Date: Thu, 16 Feb 2006 18:11:12 -0800
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...
OK, I will do a short version and Jerry can do the epic later.
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.
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.
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!
Chuck
--
Coming in 2006 - an introduction to web applications using WebObjects
and Xcode http://www.global-village.net/wointro
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems. http://www.global-village.net/products/practical_webobjects
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