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Closed 10 years ago.
I am developing a website in C# and ASP.NET MVC where people can manage their own web pages. At the moment I am using the permalink solution of StackOverflow but I am not sure if this will work in my situation because people will add and delete pages constantly. This means that the id in the pages table will grow very large.
Example: mydomain.com/page/17745288223/my-page-title
Is there a better solution?
I think that for your case (users creating pages) it's actually more user friendly to put all pages created by a single user under his/her own path i.e.:
mydomain.com/page/{username/nickname/some-name-selected-by-user}/my-page-title
If you don't want to use such format an int or long in URL will probably do.
Well, you could use some kind of a hash to make lookups more efficient. You could, for instance compute a SHA-1 hash of page title, creating date, user information, etc. - just like git does for commit ids.
Or you could use simple numbers, but convert them into some compact representation using hexadecimal numbers or alphanumerical characters like some url-shortening services.
Though this started as a comment I decided it was growing larger so here it is again..
The page id solution seems just fine.
What are you worried about? If you are expecting a few million pages that's 7 characters. If you are expecting more than a few billion pages that's 9 - 10 characters.. Pretty manageable, I think.
You could also represent it as hex and reduce it to a maximum of 8 characters to fit up to 2^32 different ids.
This means that the id in the pages table will grow very large.
What's the problem with that?
The largest value for an int is also very large (just over 2 billion) so I doubt it will hit any limit unless you are planning to have millions of users with thousands of pages each.
If you are still worried then you can use a long (64-bit integer). It can handle trillions of users with millions of pages each. Note that the population of the Earth is only a few billion.
Related
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Closed 10 years ago.
I am currently working on .net 4.5 application that contains multi lingual data.
I am new to this so I am looking for resources that explain concepts such as encoding for different languages, globalization, localization etc.
Any tips as to where I should look for such information?
MSDN - as always - is the best resource: http://msdn.microsoft.com/en-us/library/h6270d0z.aspx .
Some gotchas from my own experience:
Use unicode types in your database. So for SQL Server, make your text types nvarchar, ntext instead of varchar, text to have them as unicode. Otherwise you will lose information in languages such as Chinese
Make your design flexible, a phrase that is 10 characters in English could easily be 3-4 times as big in German or French, make your buttons flexible (sliding door technique for example for html), make your width and heights percentages and as responsive as possible.
In your resource files, have plural and singular forms of strings with placeholders for numbers, for example, if you have a phrase stating "within 2 km of this place" then you will probably need a resource entry for Km separately from the whole sentence for scenarios of singular/plural (kilometers, kilometer) don't assume that you could just add an "s" for pluralization. That won't work in all languages. Some languages even have a special case for singular, plural and for two objects that are not treated the same as plural (i.e. arabic) (Look at Dwayne's comment for an interesting intake on this point)
If you're going to localize for a language such as Arabic or Hebrew, then these are right to left, your whole design (including pictures) will need to change orientation. In HTML, that's as easy - mostly - as having a "dir: rtl" attribute, but sometimes it can be tricky.
It's not just about translation. Things that will change include number formats, using comma seperators or periods for decimal points and thousands, currency symbols coming before or after, currency formatting, date formatting etc... Make sure that all of these are formatted by .net framework using the culture of the current user.
Be disciplined about not hardcoding any strings in your UI. A handy trick is to have a resource language for a language that doesn't use latin characters (Chinese, Russian, Arabic whatever), create a resource file for that language and fill all entries with random string from Google in that language. Run your application, and you will be able to easily spot the parts of the UI that are not coming from the resource file (they will be the english characters in the middle of the Chinese ones).
It is not just about the UI. If you are sending messages from the backend, like a response from a service or so on, that also needs to be localized. In some cases, even error messages logged in the Event log are required to be localized. Make sure you think about that.
Javascript. If you're doing ajaxified web with heavy javascript, you might need to use a library such jquery localization to help with localization. You will have to serve your resource file in a JS key-value kind of structure. Since this is less standard than ASP.NET, it could require some improvisation from your side depending on your needs (decisions such as how to load these files with resources, all-at-once or with AMD, or may be create a service that returns the localized strings, or just let asp.net bind the values from the actual resource file at compile time etc...)
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Closed 10 years ago.
I would like to store world cities in a list since metro app can't have local database but I am not sure it is possible (I've found a text file with more than 3 million cities).
I wonder how they did in the weather app. Since there is no latentcy in the results suggested (in the search charm or in the "favorite places" screen), I don't think they use a webservice, and also I want my app to be able to propose a list of cities even if there is no connection available.
Any idea ?
Simply stick it in a text file, delimited by line. This is not a large amount of data - you can likely hold it all in RAM in one go.
Using a database just for this one list seems a little overkill.
With some rough calculations, assuming names of around 20 characters each, I'm in the region of about 100MB of city data. That's not insignificant for one list in memory - granted, but it's not a lot to have to contend with.
You may even be able to use something like a Linq to Text provider.
How they may have done it in the charm is to only worry about a few cities - the favourites and whatever your location service last reported. Handling < 10 is easier than 3 million.
3 million cities might sound like a lot. But is it a lot for your Metro app?
These are very rough estimates
Let's use an average city name length of 20 unicode characters.
20 * 3 million = 60 million unicode characters.
60 million * 2 bytes per unicode character = 120 million bytes.
120 million bytes / 1024 = 117,187.5 kilobytes
117,187.5 kilobytes / 1024 = 114 megabytes
~115mb isn't exactly 'small' but depending on your other requirements - you can probably handle loading 150mb into memory. You can use whatever .NET objects you'd typically use like List and use LINQ to get the matching cities or whatever.
That's not to say this is your only option. It's just probably a viable one. There is a lot of very clever stuff you could do to avoid pulling all of it into memory at once; but if you want to eliminate/minimize lag - that's going to be your best bet.
I would suggest looking into SQLite if you need a database. Metro applications obviously do not have access to SQL Server and other Win32-based DBMS, but you could try SQLite as a lightweight alternative.
Try this: https://github.com/doo/SQLite3-WinRT
We recommend using SQLite database with LinqConnect - Devart's LINQ to SQL compatible solution which supports SQLite. You can employ LINQ and ADO.NET interfaces with our product. Starting from the 4.0 version, LinqConnect supports Windows Metro applications: http://blogs.devart.com/dotconnect/linqconnect-for-metro-quick-start-guide.html.
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Closed 11 years ago.
I have a PHP script now looping through combinations of a set of arrays. I can test 6.1 Billion of the 500 Trillion total combinations in 1 hour with a simple PHP script. Is it possible to write a program in any language running on todays average PC that would be able to test all 500 Trillion combinations of multiple arrays in less than ~6 hours?
Also, I do not have the resources to use distributed or cluster computing for this task. What kind of gains could I expected converting the code to multithreaded java/c#?
Thank you
Let's start simple. Do you use threading? If not - a modern higher end Intel today has 12 hardware threads per processor. This means you get a factor of 12 from threading.
If someone gets a server specific for that he could get 24-32 hardware threads easily for relatively low cost.
If the arrays are semi static and you asume adecent graphics card, you may find having from 800 to 3000 processor cores a huge time saver. Nothing beats this - and even average CPU's have quite some core capabilities in their chips or the graphics cards these days.
500 trillion comparisons in 6 hours
=
83.3 trillion comparisons in 1 hour
=
1.4 trillion comparisons per minute
=
23.1 billion comparisons per second
Assuming you've got an Intel Core i7-2600 cpu (3.4GHz), which is 4 cores + hyperthreading = 8 cores, you'd need a per-core speed of
23.1/6 = 3.9GHz
which is at the extreme end of possibility for basic overclocking.
Once you factor in other overhead, what you want is not possible. Your cpu cannot do NOTHING BUT COMPARISONS.
If you don't have the resources then I'm afraid to say, with the numbers you want, you are buggered.
You'll need to rethink your data structures and the algorithms working on them to have any chance of completing your puzzle within the time limit - using PHP or any other language.
I know nothing about the process you want to run and maybe there is no way to achieve your goals with your current resources, but since you are asking for a language, and it is true that PHP is not the best one to tackle paralelism, I should say that Erlang is famous for that kind of achievements.
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Closed 11 years ago.
I've just read this page http://weblogs.asp.net/scottgu/archive/2010/06/10/jquery-globalization-plugin-from-microsoft.aspx
One of the things they did was to convert the arabic date to the arabic calendar. I'm wondering if it is a good idea at all to do so. Will it actually be annoying/confusing for the user (even if the user is Arabic).
Also, my second question is that do we really need to change 3,899.99 to 3.899,99 for some cultures like German? I mean it doesn't hurt to do so since the library already does it for us but wouldn't this actually cause more confusion to the user (even if he is German).
I'm sure whatever culture these people come from, if i give you a number 3,899.99 there's no way you'd get that wrong right? (since he'd probably learned the universal format anyway)
Your problem here seems to be a bad assumption. There is no "universal format" for numbers. 3,899.99 is valid in some places, and confusing in others. Same for the converse. People can often figure out what they need to (especially if it's in software that is clearly doing a shoddy job of localization otherwise. :) ), but that's not the point.
Except in certain scientific and technical domains that general software doesn't usually address, there's no universal format for any of these things. If you want your software to be accepted on native terms anywhere but your own place, you'll need to work for it.
To me it seems like it would be much less confusing to see dates and numbers in the format you're used to (in your country or language) - why do you think it would be the other way around?
The point of localization is to make your application look more natural for the user. It is definitely advisable to do this in your application if you use it internationally. While you can use US standards, that is not very customer-friendly way of doing things.
How would it be more confusing to a person to see the format they are familiar with? Meet people where they are with your application. If their standard is 10.000,00 and you are showing them 10,000.00, even if they understand it, it does make it a bit disconcerting. Reverse the situation and think what you would like. Would you like a developer using 10.000,00 for their application because you can understand it just fine?
Depends. 3.899,99 to me looks like two numbers. 3.899 and 99. I imagine our number formatting looks similarly funny to foreigners. Sure, I could guess what it means here, but what if you had a whole bunch of numbers like this clustered together? The winning lotto numbers are 45,26,21,56,94,13. Is that one big number, or 6 2-digit numbers?
Date formatting is especially important. 01/02/03. Is that Jan 2 2003, Feb 1 2003, Feb 3 2001 or what? Different cultures specify the d/m/y in different orders. Also, when spelled out, they obviously have different names for the months.
If you have the time and resources to internationalize it, I think you should.
As a foreigner myself, I can assure you that localization helps a lot in terms of user satisfaction. Commas or dots in numbers may induce big mistakes. Another on is the relative position of days and months.
To improve even further, create translations and add an option to choose locale. That way you will have close to 100% customer satisfaction
another important thing is input. if you don't have localization, take the user input "1.234"... what does the user mean? 1.234 or 1234 ? ... there may be users that don't like their values to be off by factor 1000 ... who knows? ;)
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Closed 10 years ago.
I'm searching for code in c# that can kill computer performance (CPU performance, maybe cpu - memory link performance too) as much as it is possible (it will run on 4 core box so I'm going to create 4 threads and run it simultaneously).
Should it work on int / double / numeric data type / should it have some crazy data structures (but it should not take too much memory) .
Do you have any suggestions ?
Calculate PI using all processors.
You could use parallel Linq to generate a Mandelbrot (Jon Skeet has the code readily available).
Have a program that writes copies of its executable to the drive multiple times for each thread. Have each of these copies of the program then triggered by the program. :)
If you want to kill a machine's performance, try hitting the disk, because IO interrupts tend to affect everything even on a good CPU scheduler. Something like enumerating a directory of many little files, or writing a lot of big files to disk would do the trick.
Why re-invent the wheel? Use existing Load Testing software.
Calculate a long sequence of prime numbers. The following link contains code that can be modified to do this..
Program to find prime numbers
Call Bitmap.GetPixel, in a loop, in an image processing application.
I would say: a naieve (brute force) travelling salesman implementation:
(from wikipedia):
The Travelling Salesman Problem (TSP) is an NP-hard problem in combinatorial optimization studied in operations research and theoretical computer science. Given a list of cities and their pairwise distances, the task is to find a shortest possible tour that visits each city exactly once.
Brute force solving of N Queens (see wikipedia) for for example 64 queens.
Because a simple loop like this can be optimized away (sometimes only after a few minutes already running):
while(true) {
i++;
}
You can, as well, resolve a very long encrypted message, encrypted by a key such as 2048 bits.
That's a killer.
An open-source, multithreaded 3D modeling program rendering an extremely complex lighted scene will pound the strongest system into submission.
Okay, how about some infinite recursion in the spirit of StackOverflow?
void deathToAllRobots(int someMeaninglessValue) {
deathToAllRobots(someMeaninglessValue+1);
}
int *x;
while(1)
{
x = new int[10];
}