Oracle Express Project And Oracle Express Programmer

Oracle Express Project And Oracle Express Programmer

Post by O.S.Muralishanka » Sun, 31 Dec 1899 09:00:00



I am looking for a vendor who can take up a project using Oracle Express
Database and Oralce OLAP Tools.  A system is already in place and the
project involves performance tuning of the system, WEB enabling of the
system, and some enhancements.  The Project Scope is quite big and the

if you are a vendor and you have a big team to do such projects in Oracle
Express Database.

I am also in the look out of a Programmer who has experience in Oracle
Express Database programming.  Interested parties, please send me an EMail

 
 
 

Oracle Express Project And Oracle Express Programmer

Post by wei.. » Sun, 31 Dec 1899 09:00:00


hi, All

I have developed a multi user web based database system. but I have one
problem I can not solve. How to handle concurrence control

For example, I have one room for many people to book, I can first check
if the time slot has been booked or not. If it is not booked, then you
can book the room at the time slot successfully.

If one person checked the time slot is Ok, but the system did not
insert the new booking immediately. Another person also check the time
and find it is ook. Later on, the system insert both booking and cause
double booking for the same time slot.

I would be very grateful if anyone could give me a hand on this.

thanks and have a wonderful holiday.

Wei

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

Oracle Express Project And Oracle Express Programmer

Post by C. Ferguso » Sun, 31 Dec 1899 09:00:00


select .... for update
See docs for syntax.

> hi, All

> I have developed a multi user web based database system. but I have one
> problem I can not solve. How to handle concurrence control

> For example, I have one room for many people to book, I can first check
> if the time slot has been booked or not. If it is not booked, then you
> can book the room at the time slot successfully.

> If one person checked the time slot is Ok, but the system did not
> insert the new booking immediately. Another person also check the time
> and find it is ook. Later on, the system insert both booking and cause
> double booking for the same time slot.

> I would be very grateful if anyone could give me a hand on this.

> thanks and have a wonderful holiday.

> Wei

> Sent via Deja.com http://www.deja.com/
> Before you buy.

 
 
 

Oracle Express Project And Oracle Express Programmer

Post by yong.. » Sun, 31 Dec 1899 09:00:00


It's me again. I hit the Submit button too quickly. On second thought,
there's an "artificial" way to do this. When A runs select to
find that the room is unbooked, you insert into a table called, say,
mutex, a number, indicating this room is being checked by someone.
Obviously you also need to insert the room number and the time this
happens. This time is important. You use it to time out A's pondering on
his Web page. (What if he checks and leaves office for the day?) When B
comes in, if the room is unbooked or if booked but A's checking time has
expired, insert into the mutex table for B, replacing whatever A left
behind.

Let me know what you all say about this strategy.

Yong Huang

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

Oracle Express Project And Oracle Express Programmer

Post by Yong » Sun, 31 Dec 1899 09:00:00


For some reason, I posted a followup to my own message but it didn't
appear. What I want to supplement is that, you can "artificially"
implement this concurrency control. You create a table called, say,
mutex with the column roomnum, personchecking, and timechecked. When A
checks and finds that the room is available through a select statement,
the database server also inserts the room number into mutext(roomnum),
'A' into personchecking and that moment of time into timechecked. Let's
say you set the expiration time for holding this room at 5 minutes.
Assuming A doesn't book the room within 5 minutes, when B comes in
within 5 minutes, he'll see roomnum is on hold; if after 5 minutes,
it's available and he can hold it...
<p>
You got the idea.

Yong Huang<br>

Web: http://www.stormloader.com/yonghuang/

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Oracle Express Project And Oracle Express Programmer

Post by DNP » Sun, 31 Dec 1899 09:00:00


Greetings to all on the newsgroup --

concurrecny control and stateless web serving - I think the only
solution is to reduce as far as possible the statelessness of the
situation i.e. to shortern the time between checking to see whether a
room is booked and actually booking it. Although this sounds obvious, it
really is the only solution short of having a completely invisible
process (where the user is only told of a double-booking-induced failure
after trying to book).

Keeping the whole process invisible right up to the point of booking
lets you offload most of the cleverness to Oracle, because it will know
if a room is booked or not. Because you only have to trap for one kind
of error (inability to update the table etc. etc.) , you should be able
to make the whole process of [trying to book and reporting a failure
when it occurs] quite lightweight and fast.

Imagine if the user could try and book near instaneously. It wouldn't
take them too long to find a free slot. You could of course create a
snapshot / semi-static page of the current bookings - perhaps updating
it every half our or hour.

Doing this saves you the classic mistake of coming up with ever more
complicated and awkward shared and intent / shared-intent locking
schemes. These are frowned upon in Oracle circles, make no doubt about
it.

Hope that gives you food for thought.

 
 
 

1. Oracle Express Project And Oracle Express Database Programmer

I am looking for a vendor who can take up a project using Oracle Express
Database and Oralce OLAP Tools.  A system is already in place and the
project involves performance tuning of the system, WEB enabling of the
system, and some enhancements.  The Project Scope is quite big and the

if you are a vendor and you have a big team to do such projects in Oracle
Express Database.

I am also in the look out of a Programmer who has experience in Oracle
Express Database programming.  Interested parties, please send me an EMail

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