Re: how to insert records in database in the order of insertion to EC
Re: how to insert records in database in the order of insertion to EC
- Subject: Re: how to insert records in database in the order of insertion to EC
- From: Chuck Hill <email@hidden>
- Date: Sat, 31 Oct 2009 21:04:31 -0700
On Oct 31, 2009, at 8:46 PM, Shravan Kumar. M wrote:
Thanks so much for your quick response Chuck.
We use Frontbase. I have no FK issue here. It's just that the
objects should be inserted to DB in the order I have created and
inserted into EC.
Why EC saveChanges() operation just not save the objects in the
order of insertion??? Isn't it simple? I believe EC maintains an
array insertedObjects(), so it should just follow that array order,
unless otherwise any constraints as you have mentioned!!! Just
trying to understand the mystery behind the complexity :)
For what you want, it would not matter if it did. The defined order
of records in an un-ordered Select (a select with no Order By clause)
is indeterminate. The database is free to change the order of such
result sets to return the result set in the shortest amount of time or
any other reason it might have.
If there's no built-in solution, then probably adding a "sortOrder"
field to my table would fix this issue.
That is the ONLY solution you can depend on.
Chuck
From: Chuck Hill <email@hidden>
To: Shravan Kumar. M <email@hidden>
Cc: WO Dev Group <email@hidden>
Sent: Sun, November 1, 2009 8:49:54 AM
Subject: Re: how to insert records in database in the order of
insertion to EC
On Oct 31, 2009, at 6:57 PM, Shravan Kumar. M wrote:
> Hi Group,
>
> Could any one please advise me how can I insert records in
database in a specific order or as per the order of insertion of
objects to EditingContext
AFAIK, you can't. The order of insertion is not tracked.
> for eg:
>
> I have inserted objects to EC in the following order: A1, A2, A3,
A4, A5 (and then saved the EC once - editingContext.saveChanges())
> But, when these got saved to database the order is disturbed and
is not guaranteed i.e., I see following order sometimes: A2, A5, A1,
A3, A4, whereas I want the order of these objects as I have inserted
to EC.
>
> I heard that we can do something with AdaptorOperations, but not
sure of that exactly and am trying to see if we have an higher level
API for that. (Just a note: We do not use Wonder to the fullest, of
course we use Wonder API's as required.)
If your problem is FK constraint violations, make the constraints
DEFERRABLE INITIALLY DEFERRED when you create them.
If you are using MS SQL Server, then you are in a world of hurt. It
includes not supporting deferrable constraints in its set of
unsupported yet highly desirable features. There is a reason why
people mock that "database". You can order the operations using EOF
but (a) is isn't easy and (b) you can't expect to know the order of
insertion and (c) I can't think of many useful examples to follow.
You could start with the source for myhttp://www.global-village.net/chill/ms_sql_server_eof_plugin
Chuck
--Chuck Hill Senior Consultant / VP Development
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
--
Chuck Hill Senior Consultant / VP Development
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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