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: Chuck Hill <email@hidden>
- Date: Tue, 1 Nov 2005 10:51:55 -0800
On Nov 1, 2005, at 10:30 AM, Luis Miguel Espinoza wrote:
1. Is faster for EO use one Column as lock or faster use all fields
that I consider to need for lock,? Can it make slower or faster
my application or if I use anyone my applicaction benchmark will be
equal??
Compared to everything else that runs as part of your application, it
won't make any difference what you lock on (well, other than large
BLOB/CLOB fields). As long as the PK is used for locking (and you
can NOT avoid this!), the cost will be for the database to make some
field value comparisons on a single row. This will be very fast and
not something I'd even bother to think about.
I use multiple columns as I then don't need to worry about setting a
timestamp or incrementing a field and I can be selective in what
causes an optimistic locking failure.
Chuck
2. What's about reports ?? What is better solution? I was tried
JFreeReport in JSP application. I was reading some books (sams,
wrox, etc). I know how export to excel o html, but what about
Groups Reports with Sum, Total, etc..
Thanks all for your soon answer, because that is critical point,
because I have my eomodel finished, and I don't want use Timestamp
as my other older JSP aplications, and WebObjects present to me
other best solutions.
Luis M.
NOTE: Sorry for my english.
On Nov 1, 2005, at 12:00 PM, Ken Anderson wrote:
On Nov 1, 2005, at 12:40 PM, 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??
The fields you use for locking are completely based on your
needs. Personally, I like to have a transactionID (an int) on
each record that gets updated every time the record changes.
Therefore, I can lock on that and nothing else. If you can allow
the possibility of users stepping on someone else's change, you
can lock only the important ones. What EOF basically does is take
all the fields that have the lock next to them and verify that
that record still exists in the database with those values prior
to saving.
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??
The best practice is to have a single integer primary key that is
not used by the user. If you are starting a new project, this is
certainly the way to go, since all your foreign keys can be simple
integers. I would never have a primary key other than a unique
integer that users never see. If you have to use an existing
database, do what you have to!
Thanks , and sorry if my question are begginer question??
Luis M.
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