Re: What's is better solution for Lock? Use Timestamp or "mark all fields"
Re: What's is better solution for Lock? Use Timestamp or "mark all fields"
- Subject: Re: What's is better solution for Lock? Use Timestamp or "mark all fields"
- From: Arturo Perez <email@hidden>
- Date: Tue, 01 Nov 2005 13:10:03 -0500
Luis Miguel Espinoza wrote:
Good day everybody,
I am new into WebObjects environment, and I want begin to the right way
into webobjects programming.
I have some questions, and hope you answer me in base your experience a
solutions.
1. Is better use Timestamp field as lock?? or May I use all fields as
lock into EOModel??
Depending on your database Timestamp fields don't always compare equal.
They often differ at the millisecond value. I would avoid them as locks
for this reason. You can use all fields as lock but, again, avoid
those with precision that's too high (like BigDecimal, etc). Generally
speaking, it's best to pick a few fields that you know accurately signal
when a row has been updated by someone else using SQL or by another
WebObjects Instance.
2. Is good practice use one field as PrimaryKey (as webobjects tutorial
say) or must I use composed PrimaryKeys when I have to use them??
That's up to you. Compound primary keys are required by join tables.
I've rarely needed compound primary keys, although I have often needed
compound unique keys.
The best practice is to use primary keys that are meaningless to your
users and to let WebObjects have total control over them. Alternate
keys are your friend. WebObjects uses primary key as THE object
identifier so note that once WO knows the primary key for something that
it really, really, REALLY does not like you to change them.
Thanks , and sorry if my question are begginer question??
Luis M.
You're welcome. Keep the questions coming.
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