Re: initiate content of NSArray
Re: initiate content of NSArray
- Subject: Re: initiate content of NSArray
- From: "Jonathan Fleming" <email@hidden>
- Date: Wed, 23 Jun 2004 03:27:41 +0100
Hi Goh,
I think this will help you, it's an post I kept from Jonathan Rochkind:
From:
Jonathan Rochkind <email@hidden>
Re: updating multiple objects at once
Date:
Mon, 15 Sep 2003 13:33:07 -0500
No matter what, multiple update statements will be sent to the db. But, they
will be sent in one transaction when you call saveChanges().
It's a little known fact about NSArray, that it implements takeValueForKey
to call the same named method with the same arguments on each of the
elements of the array. And takeValueForKey on an EO will call the
single-argument method with the name 'key'.
So you should be able to do something like:
fetchedObjects.takeValueForKey( new Boolean(false), "someBooleanAttribute");
to set "someBooleanAttribute" to false on all the objects. You will still
need to call editingContext.saveChanges() to commit those changes to the db.
This saves just two or three lines of code from iterating though things by
hand. The compiled code is no more efficient whatsoever then just looping
through things by hand. Personally, I'd just loop through things by hand, to
make the code more clear (to someone who is confused by the takeValueForKey
call), and to avoid putting a method name in a String literal---if you ever
change the name of someBooleanAttribute, the takeValueForKey call will still
compile, but will product a runtime exception.
HTH
Jonathan F :^)
From: Goh Keng Boon <email@hidden>
To: wojingo <email@hidden>
CC: WebObjects Developer <email@hidden>
Subject: Re: initiate content of NSArray
Date: Wed, 23 Jun 2004 09:48:56 +0800
Hi can you explain in detail how to do that?
I've already fetch all content into an NSArray and bind this array to List
of WORepetition, i need to set value for one of the attribute inside that
NSArray(for every record),
so i'm not sure how to set that? Am i going to loop through the NSArray to
set them record by record?
KB
On 22-Jun-04, at 11:52 PM, wojingo wrote:
Hi,
I think you could use awakeFromFetch(called for you when fetched from
DB:) and awakeFromInsertion (called for you when its inserted into an
editingContext).
HTH.
regards
-
shaun
On Tue, 2004-06-22 at 21:36, Goh Keng Boon wrote:
Hi,
I got this EO called "Invoice" and it has a to many relationship with
"InvoiceItem"
By using "Invoice", i'm able to display all then content and put
Invoice.relationwithinvoiceitem in the List of WORepetition
as well as anInvoiceItem in the item of WORepetition
I would like to set some value to every anInvoiceItem, so that after it
listed by the WORepetition, there will have some default
values there, may i know how can i do that? Thanks
KB
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