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Would anyone be interested in an article demonstrating a component that does High-Low identifiers as an alternative to Identity columns in SQL?
For those not familiar, the idea is that you assign a unique id to a row of data before it is ever saved (in code). This has several benefits, like (off the top of my head, I'm sure there are more):
* Row Ids are unique, even across tables
* Replication is greatly simplified
* Inserts are fast (because we don't need a select query to get back the @@IDENTITY)
* SELECTs are also fast, since recent SQL databases have native support for Guids.
The High-Low term refers to the specific technique used to do this in a way that guarantees uniqueness.
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I have used this method many times in the past. It has only one draw back. GUID's are not inherently sortable on SQL. This can hurt paging schemes (i.e. Give me the first 10 then the next 10) and random picking (i.e. random drug testing).
Solving these issues is more informative then simply choosing a GUID for your primary key.
By the way, joins & indexes are a little slower with GUIDs then with INTs. Nothing measurable until you get into large tables but, they are slower.
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Hi, I need to download files from a web site (not FTP site), is there a way to do it?
Thanks
Xin Liu
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Hello
I just want to learn a modern programing language and i dont know what to do !
i know a little of traditional c++ and visual c++.net but i want to
choose one of these : "visual c++.net" or "visual c#.net".
now would u please guide me to choose one of these? and would u please say me which one is better or differences between them?
thank u very
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We should not make that choice for you!
C++.NET is often referred to as managed C++. Since you can care less about resourses and memory, your development time is reduced. I don't know the details about managed C++.
C# is a whole different thing. Besides the fact that it is a managed language, it also is 100% object oriented (like Java).
The major advantage is that your development time decreases a lot, but your distributable becomes bigger and slower.
I recommand that you read a few articles about Managed C++ and C# that can be found on msdn[^], and then choose the language that you feel comfortable with.
A student knows little about a lot.
A professor knows a lot about little.
I know everything about nothing.
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Does anyone need code to convert SELECT statements with INNER JOINs from SQL Server syntax to Access compatible syntax? Access requires brackets, as it is known.
It's a weird thing, however, it's useful when you need to support both Access and SQL Server as backend, and don't want to duplicate the queries.
Regards,
Serge (Logic Software, Easy Projects .NET site)
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You can also use brackets in SQL, so you can write the queries for Access and re-use them on SQL server 
"Every rule in a world of bits and bytes can be bend or eventually be broken"
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em.. as far as i know, there are articles on how to snap MDI children and such, but how do you snap dialogs in a dialog based app?? smells like a simple and usefull article.. (i nearly wrote 'teen spirit' )
---
kick ash.
http://sprdsoft.cmar-net.org
http://t1tan.cjb.net
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Sounds indeed like a good article, will take a look at it. You will hear from me again soon
"Every rule in a world of bits and bytes can be bend or eventually be broken"
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I hope so Thanx!
---
YOU KNOW WHAT YOU ARE BLONDIE!?!? YOU'RE JUST A SON OF A BA A A A AAAAAAAAAA!!!!!
http://sprdsoft.cmar-net.org
http://t1tan.cjb.net
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Im going to create an add-on to msn messneger client that among other things saves the history of a contacts state changes, i.e offline to online etc.
I want to keep a log so that a profile can be built up over time (24hours) when a contact is online at times through out the day. So the user with that contact can see when the best time is to try and catch the contact online.
The problem is, how to record state changes when the user is not online themselves. Thus keeping the information useful.
I need some way of retreving state changes of contacts without the user being online. Then when the user signs into messenger the profile can be updated.
Im not sure if its feasible, so i thought id put the problem on here.
cheers for any comments
mike
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If you're not online... how are you going to know if anyone else is?
Your app would have to keep the MSN client up and running 24 hours a day to know when other people are on...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Dave Kreskowiak wrote:
Your app would have to keep the MSN client up and running 24 hours a day to know when other people are on...
hmm, that gives me just a germ of an idea, but how about something like this: Create a web service on a dedicated server (maybe at a hosting facility, whatever). It would have a few methods:
StartTrackingUser(UserName)
GetUserStats(UserName)
StopTrackingUser(UserName)
When somebody wants to start tracking another user, they call your StartTrackingUser() function which creates an entry in the database and sets up a user for tracking. Then you have a service (or just a thread) running that reads your database and checks all of the users int there every X minutes to see if they are online. It then writes an approraite entry to the DB. (If the user was online but is not off, it can write "userX logged of at..." or visa-versa.)
When you want to get the stats back form the server, just call your GetUserStats which compiles the stats (or gets them raw, whatever) from the database.
Finally, when you want to stop tracking a person, your app calls StopTrackingUser().
This all depends on finding a hosting service that wil lallow you to run a scheduled task or a service or having a dedicated server at a static IP address.
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pnjoyce wrote:
This all depends on finding a hosting service that wil lallow you to run a scheduled task or a service or having a dedicated server at a static IP address.
That'll cost you some serious coinage. Is the function of this thing really worth that kind of money?
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Had a good look around and there isn't much in the way of examples of business application on this site - so I've decided to do a small business accounts system (for my small business) and write it up. Anyone interested or knowledgeable to help?
'--8<------------------------
Ex Datis:
Duncan Jones
Merrion Computing Ltd
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Merrion wrote:
there isn't much in the way of examples of business application on this site
Merrion wrote:
Anyone interested
Looks like you've found a hole in the market. So long as it is interesting I'm sure people would be appreciative of the article.
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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I write business apps in C# and I've thought about doing something for Code Project on the subject, but I thought someone would come along and accuse me of being a closet VBer (not that there's anything wrong with that  ).
Anyway, I think it would be useful, so I say go for it.
Charlie
if(!curlies){ return; }
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I am working on the same kind of application, maybe we can help eachother out?
"Every rule in a world of bits and bytes can be bend or eventually be broken"
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I've been trying to architect an application that will expose an object model similar to MS Office Applications. It will have a Top-level Application Object and some Document objects. I've been at this for nearly a week now and I have discarded everything I've tried. Any suggestions??
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Break it down into sections. What you want to expose, what you need to expose. Then sub group them into objects and collections. Then you pretty much have your DOM you just have to supply the methods, properties, and abilities you want them to do and have them interact with your application.
Cheers,
-Erik
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This is what I'vd got so far.
<br />
public sub main()<br />
dim app as new App<br />
<br />
app.run<br />
end sub<br />
<br />
public class App<br />
private frm as new system.windows.forms.form<br />
private mDocs as new DocumentCollection 'Documents Collection<br />
<br />
public sub Run()<br />
application.run(frm)<br />
end sub<br />
end class<br />
<br />
public class DocumentCollection<br />
inherits CollectionBase<br />
'Omitted for brevity, Normal CollectionBase implementation<br />
end class<br />
Question is: How do I get the currently running instance of the App Class from another application? I would like to be able to allow other applications to get my App Object through calls like GetObject(,"Excel.Application") returns the currently running instance of an Excel.Application Object. Is there a .NET method similar to VB'6 GetObject? Is there also a .NET Method similar to RegisterActiveObject?
Thanks.
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I don't know of any .NET BCL method that does this, but you can put your main application class into the ROT (Running Object Table) using the COM RegisterActiveObject() method as you mentioned. This is what a BCL registration method would do if there was one.
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Currently I am working on a protocol analyzer project. I have traces of that protocol (say a point-2-point data/control protocol) stored in files. My protocol analyzer should check for the syntactic correctness as well as the semantic correctness (the correct flow/order as specified in the Spec).
Since we decided against hardcoding all the rule-checkings in the main program, the rules are put in a separate file & the inference engine loads these rules and checks for the validity of the data (from the trace files).
I thought of embedding a prolog interpreter and writing all the rules in the predicate format. But, this seems to take a pretty big performance hit. Also, another idea is, developing an interpreter for a small, powerful embedded language like Lua or SMALL -- the problem here is, these lack the flexibility of a logic programming language like Prolog.
I am sort of confused as to which approach I should pursue. Or, is there a better way?
I'd appreciate if any of you can share some ideas regarding this with me or any online references to projects which have the same nature.
Thx a lot.
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There is a project for checking cryptographic protocols:
http://www.cryptyc.org/intro.html
you might want to download it, since it's open source maybe you can modify the sources to fit your needs.
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