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Credit Card storage solution

- by jtnire

Hi Everyone, I'm developing a solution that is designed to store membership details, as well as credit card details. I'm trying to comply with PCI DSS as much as I can. Here is my design so far: PAN = Primary account number == long number on credit card Server A is a remote server. It stores all membership details (Names, Address etc..) and provides indivudal Key A's for each PAN stored Server B is a local server, and actually holds the encrypted PANs, as well as Key B, and does the decryption. To get a PAN, the client has to authenticate with BOTH servers, ask Server A for the respective Key A, then give Key A to server B, which will return the PAN to the client (provided authentication was sucessful). Server A will only ever encrypt Key A with Server B's public Key, as it will have it beforehand. Server B will probably have to send a salt first though, however I doin't think that has to be encrypted I havn't really thought about any implementation (i.e. coding) specifics yet regarding the above, however the solution is using Java's Cajo framework (wrapper for RMI) so that is how the servers will communicate with each other (Currently, membership details are transfered in this way). The reason why I want Server B to do the decryption, and not the client, is that I am afraid of decryption keys going into the client's RAM, even though it's probably just as bad on the server... Can anyone see anything wrong with the above design? It doesn't matter if the above has to be changed. Thanks jtnire

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ReaderWriterLockSlim and Pulse/Wait

- by Jono

Is there an equivalent of Monitor.Pulse and Monitor.Wait that I can use in conjunction with a ReaderWriterLockSlim? I have a class where I've encapsulated multi-threaded access to an underlying queue. To enqueue something, I acquire a lock that protects the underlying queue (and a couple of other objects) then add the item and Monitor.Pulse the locked object to signal that something was added to the queue. public void Enqueue(ITask task) { lock (mutex) { underlying.Enqueue(task); Monitor.Pulse(mutex); } } On the other end of the queue, I have a single background thread that continuously processes messages as they arrive on the queue. It uses Monitor.Wait when there are no items in the queue, to avoid unnecessary polling. (I consider this to be good design, but any flames (within reason) are welcome if they help me learn otherwise.) private void DequeueForProcessing(object state) { while (true) { ITask task; lock (mutex) { while (underlying.Count == 0) { Monitor.Wait(mutex); } task = underlying.Dequeue(); } Process(task); } } As more operations are added to this class (requiring read-only access to the lock protected underlying), someone suggested using ReaderWriterLockSlim. I've never used the class before, and assuming it can offer some performance benefit, I'm not against it, but only if I can keep the Pulse/Wait design.

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Accessing bitmap array in another class? C#

- by Marius Mathisen

I have this array : Bitmap[] bildeListe = new Bitmap[21]; bildeListe[0] = Properties.Resources.ål; bildeListe[1] = Properties.Resources.ant; bildeListe[2] = Properties.Resources.bird; bildeListe[3] = Properties.Resources.bear; bildeListe[4] = Properties.Resources.butterfly; bildeListe[5] = Properties.Resources.cat; bildeListe[6] = Properties.Resources.chicken; bildeListe[7] = Properties.Resources.dog; bildeListe[8] = Properties.Resources.elephant; bildeListe[9] = Properties.Resources.fish; bildeListe[10] = Properties.Resources.goat; bildeListe[11] = Properties.Resources.horse; bildeListe[12] = Properties.Resources.ladybug; bildeListe[13] = Properties.Resources.lion; bildeListe[14] = Properties.Resources.moose; bildeListe[15] = Properties.Resources.polarbear; bildeListe[16] = Properties.Resources.reke; bildeListe[17] = Properties.Resources.sheep; bildeListe[18] = Properties.Resources.snake; bildeListe[19] = Properties.Resources.spider; bildeListe[20] = Properties.Resources.turtle; I want that array and it´s content in a diffenrent class, and access it from my main form. I don´t know if should use method, function or what to use with arrays. Are there some good way for me to access for instanse bildeListe[0] in my new class?

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Seeking suggestions on redesigning the interface

- by ratkok

As a part of maintaining large piece of legacy code, we need to change part of the design mainly to make it more testable (unit testing). One of the issues we need to resolve is the existing interface between components. The interface between two components is a class that contains static methods only. Simplified example: class ABInterface { static methodA(); static methodB(); ... static methodZ(); }; The interface is used by component A so that different methods can use ABInterface::methodA() in order to prepare some input data and then invoke appropriate functions within component B. Now we are trying to redesign this interface for various reasons: Extending our unit test coverage - we need to resolve this dependency between the components and stubs/mocks are to be introduced The interface between these components diverged from the original design (ie. a lots of newer functions, used for the inter-component i/f are created outside this interface class). The code is old, changed a lot over the time and needs to be refactored. The change should not be disruptive for the rest of the system. We try to limit leaving many test-required artifacts in the production code. Performance is very important and should be no (or very minimal) degradation after the redesign. Code is OO in C++. I am looking for some ideas what approach to take. Any suggestions on how to do this efficiently?

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LINQ - Querying a list filtered via a Many-to-Many reltionship

- by user118190

Please excuse the context of my question for I did not know how to exactly word it. To not complicate things further, here's my business requirement: "bring me back all the Employees where they belong in Department "X". So when I view this, it will display all of the Employees that belong to this Department. Here's my environment: Silverlight 3 with Entity Framework 1.0 and WCF Data Services 1.0. I am able to load and bind all kinds of lists (simple), no problem. I don't feel that my environment matters and that's why I feel it is a LINQ question more than the technologies. My question is for scenarios where I have 3 tables linked, i.e. entities (collections). For example, I have this in my EDM: Employee--EmployeeProject--Project. Here's the table design from the Database: Employee (table1) ------------- EmployeeID (PK) FirstName other Attributes ... EmployeeProject (table2) ------------- EmployeeProjectID (PK) EmployeeID (FK) ProjectID (FK) AssignedDate other Attributes ... Project (table3) ------------- ProjectID (PK) Name other Attributes ... Here's the EDM design from Entity Framework: ------------------------ Employee (entity1) ------------------------ (Scalar Properties) ------------------- EmployeeID (PK) FirstName other Attributes ... ------------------- (Navigation Properties) ------------------- EmployeeProjects ------------------------ EmployeeProject (entity2) ------------------------ (Scalar Properties) ------------------- EmployeeProjectID (PK) AssignedDate other Attributes ... ------------------- (Navigation Properties) ------------------- Employee Project ------------------------ Project (entity3) ------------------------ (Scalar Properties) ------------------- ProjectID (PK) Name other Attributes ... ------------------- (Navigation Properties) ------------------- EmployeeProjects So far, I have only been able to do: var filteredList = Context.Employees .Where(e => e.EmployeeProjects.Where(ep => ep.Project.Name == "ProjectX")) NOTE: I have updated the syntax of the query after John's post. As you can see, I can only query, the related entity (EmployeeProjects). All I want is being able to filter to Project from the Employee entity. Thanks for any advice.

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How to get the most out of a 3 month intern?

- by firoso

We've got a software engineering intern coming in who's fairly competent and shows promise. There's one catch: we have him for 3 months full time and can't count on anything past that. He still has a year of school left, which is why we can't say for sure that we have him past 3 months. We have a specific project we're putting him on. How can we maximize his productivity while still giving him a positive learning experience? He wants to learn about development cycles and real-world software engineering. Anything that you think would be critical that you wish you had learned earlier? Nearly six months later: He's preformed admirably and even I have learned a lot from him. Thank you all for the input. Now I want to provide feedback to YOU! He has benefited most from sitting down and writing code. However, he has had a nasty history of bad software engineering practices which I'm trying to replace with good habits (properly finishing a method before moving on, not hacking code together, proper error channeling, etc). He has also really gained a lot by feeling involved in design decisions, even if most of the time they're related to my own design plans.

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Catchable fatal error: Object of class view_user could not be converted to string in C:\xampp\xampp\htdocs\textile\admin\view_class.php on line 9 [closed]

- by user1282142

<?php include('config.inc'); class view_user { function view($user) { $temp = mysql_query("SELECT * from register_user where user_name = '$user'"); $value = mysql_fetch_array($temp); $query = mysql_query("SELECT order_user.design_name, order_user.reaad, order_user.pick, order_user.yarn_detail FROM register_user INNER JOIN order_user ON register_user.register_id = '$value[register_id]' and order_user.register_id = $value[register_id]"); if($query) { echo "<center><table border = 1> <tr> <th>Design Name</th> <th>Read</th> <th>Pick</th> <th>Design Detail</th> </tr>"; while($row = mysql_fetch_array($query)) { echo "<tr>"; echo "<td>$row[design_name]</td>"; echo "<td>$row[reaad]</td>"; echo "<td>$row[pick]</td>"; echo "<td>$row[yarn_detail]</td>"; echo"</tr></center>"; } } else { echo"User doesn't Exist"; include('footer1.php'); } } } ?>

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iPhone toolbar shared by multiple views

- by codemonkey

Another iPhone noob question. The app I'm building needs to show a shared custom UIToolbar for multiple views (and their subviews) within a UITabBarController framework. The contents of the custom toolbar are the same across all the views. I'd like to be able to design the custom toolbar as a xib and handle UI events from its own controller class (I'm assuming I can subclass UIToolbar to do so?). That way I could define IBOutlet & IBAction items, etc. Then I could associate this custom toolbar with eachs of the UITabBarController views (and their subviews). But I'm having trouble finding out whether that's possible - and if so, how to do it. In particular, I want to be able to push new views onto UINavigationControllers that are each associated with parent UITabBarController tabs. So, to summarize, I want a: custom toolbar shared by multiple views which are managed by multiple navigation controllers and the navigation controllers are associated with different tabs of a parent tab bar controller The tab bar controller itself is launched modally, though I don't believe that's relevant. Anyway, the tab bar controller is working, as are its child navigation controllers. I'm just having a little trouble figuring out how to persist the shared toolbar to the various subviews. I'd settle for a good clean way of implementing programmatically... though I'd prefer the flexibility of keeping the toolbar's visual design in a xib. Anyone have any suggestions?

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How to catch non exist requested URL in Java servlet ?

- by Frank

My objects are stored online in two different places : <1 On my nmjava.com site, where I can put them in a directory called "Dir_My_App/Dir_ABC/" <2 On Google App Engine datastore When my Java app runs it checks both places for the objects, I designed the app so that it tries to get an object from a Url, it doesn't care whether it's an object in a directory or an object returned by a servlet. My_Object Get_Object(String Site_Url,String Object_Path) { ... get object by the name of Object_Path from the Site_Url ... } Now the request Url for my web site nmjava.com might look like this : http://nmjava.com/Dir_My_App/Dir_ABC/My_Obj_123 [ In a directory ] Or in the case of Google App Engine servlet : http://nm-java.appspot.com/Check_License/Dir_My_App/Dir_ABC/My_Obj_123 [ Non exist ] The "Object_Path" was generated by my app automatically. It can now get the object from my site by the above method like this : My_Object Get_Object("http://nmjava.com","/Dir_My_App/Dir_ABC/My_Obj_123"); In the Google App Engine, my servlet is running and ready to serve the object, if the request comes in correctly, but since I don't want to design my app to know whether the object is in one site's directory or in other site's datastore, I need to design the servlet to catch the non exist Url, such as the one above, and be able to make a call : My_Object Get_Object("http://nm-java.appspot.com/Check_License","/Dir_My_App/Dir_ABC/My_Obj_123"); So my question is : When a request comes into the servlet with a non exist Url, how should it catch it and analyze the url in order to respond properly, in my case it should know that : http://nm-java.appspot.com/Check_License/Dir_My_App/Dir_ABC/My_Obj_123 is asking for the object "My_Obj_123" [ ignore the dirs ] and return the object from the datastore. Now I'm getting this : Error: Not Found The requested URL /Check_License/Dir_My_App/Dir_ABC/My_Obj_123 was not found on this server. Where in my servlet and how do I detect the request for this non exist Url ?

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non-cached RSLs in Flex?

- by SteMa

I have a project that is for several customers, the only difference is in the DB, everything else looks the same, except for the main page's text. That is loaded from an external swf file. I created a library, compiled it as an swc, imported it and using it as an RSL. The problem is that if once I've opened the page, and afterwards update the rsl (because changes in the text are needed), than it's already cached by the browser (not the flashplayer's cache but we shouldn't discuss this please!) and the updated swf won't be loaded. If I use it as an external, the page won't even start up (the browser says it's loaded, but it's blank, not even the loading progess bar of flex appear) <local:MainPage includeIn="default" currentState="{MainPageState}" id="Page" width="100%" height="100%" /> this is the code on the main page, if I comment this out, than the whole thing loads, even with the use of the "external" link-type. If it helps, in the design view, I see the component, but I get a warning for the library: Design mode could not load MainPage.swc. It may be incompatible with this SDK, or invalid. (DesignAssetLoader.CompleteTimeout)

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What are the benefits and risks of moving to a Model Driven Architecture approach?

- by Tone

I work for a company with about 350 employees and we are in the process of growing. Our current codebase is not structured very well and we are looking both at how to improve it immediately (by organizing objects into namespaces, separating concerns, etc.) and moving to a model driven architecture approach, where we model and design everything first with uml, then generate code from that model. We have been looking heavily at Sparx Systems Enterprise Architect (EA) (which is UML 2.0 capable) and we are also considering the tools in VS 2010. I know there are other tools out there (Rational XDE being one) but I really do not think we can spend $1500+ per license at this point. I'm not looking for answers on which tool is better than another but more for experiences moving from a cowboy coding environment (that is, little planning and design, just jump in and start coding) to a model driven architecture. Looking back was it helpful to your organization? What are the pain points? What are the risks? What are the benefits?

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Dynamic GUI Framework Designing

- by user575715

There is a Scenario to be developed for a 3-tier Application .We need to design a Framework or a utility sort of thing . In tradional aspect of GUI Designing , either we tend to create a static gui page and code the elements on it along with other properties of the elements such as (disabled/enabled,image source,name ,id ,which function to be called under onclick event.) or we tend to drag and drop the elements from the control pallete provided by variety of gui frameworks. Certain things i need to design a POC so that we can develop this concept. 1) There must a utility ,such that during creation of screen layout , that screen should be saved in the database(RDBMS) with a screen number. 2) All the Events related to that control should be saved in some other table which will be dynamically mapped during the calling of screen number by the user. 3) When the user call that screen ,a generic function should be invoked which'll call the screen file from the database and apply all the properties ,events,etc at runtime and the final output will be displayed to the user. This POC will help the us to customised the screens according to our usage.also all the code will seperated which can easily be used for some other development process. Thanks Amit Kalra

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Java, Massive message processing with queue manager (trading)

- by Ronny

Hello, I would like to design a simple application (without j2ee and jms) that can process massive amount of messages (like in trading systems) I have created a service that can receive messages and place them in a queue to so that the system won't stuck when overloaded. Then I created a service (QueueService) that wraps the queue and has a pop method that pops out a message from the queue and if there is no messages returns null, this method is marked as "synchronized" for the next step. I have created a class that knows how process the message (MessageHandler) and another class that can "listen" for messages in a new thread (MessageListener). The thread has a "while(true)" and all the time tries to pop a message. If a message was returned, the thread calls the MessageHandler class and when it's done, he will ask for another message. Now, I have configured the application to open 10 MessageListener to allow multi message processing. I have now 10 threads that all time are in a loop. Is that a good design?? Can anyone reference me to some books or sites how to handle such scenario?? Thanks, Ronny

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How can I manage a FIFO-queue in an database with SQL?

- by Jonas

I have two tables in my database, one for In and one for Out. They have two columns, Quantity and Price. How can I write a SQL-query that selects the correct price? In example: If I have 3 items in for 75 and then 3 items in for 80. Then I have two out for 75, and the third out should be for 75 (X) and the fourth out should be for 80 (Y). How can I write the price query for X and Y? They should use the price from the third and forth row. In example, is there any way to SELECT the third row in the In-table? I can not use auto_increment as identifier for i.e. "third" row, because the tables will contain post for other items too. The rows will not be deleted, they will be saved for accountability reasons. SELECT Price FROM In WHERE ...? NEW database design: +----+ | In | +----+------+-------+ | Supply_ID | Price | +-----------+-------+ | 1 | 75 | | 1 | 75 | | 1 | 75 | | 2 | 80 | | 2 | 80 | +-----------+-------+ +-----+ | Out | +-----+-------+-------+ | Delivery_ID | Price | +-------------+-------+ | 1 | 75 | | 1 | 75 | | 2 | X | <- ? | 3 | Y | <- ? +-------------+-------+ OLD database design: +----+ | In | +----+------+----------+-------+ | Supply_ID | Quantity | Price | +-----------+----------+-------+ | 1 | 3 | 75 | | 2 | 3 | 80 | +-----------+----------+-------+ +-----+ | Out | +-----+-------+----------+-------+ | Delivery_ID | Quantity | Price | +-------------+----------+-------+ | 1 | 2 | 75 | | 2 | 1 | X | <- ? | 3 | 1 | Y | <- ? +-------------+----------+-------+

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How does Crystal Reports Runtime Licensing work?

- by GluedHands

I am designing an application in C# and I want to use some Crystal Reports in my application. I am selling this application as freelance to a small business. This is my first program that I have ever sold. I have Crystal Reports 2008 that I am using to design reports with. Do I need to get any kind of licensing from Business Objects to include the Crystal Reports Runtime for report printing in my application? Or do I not need to worry about it as long as I have a licensed version of Crystal Reports 2008 on my development machine. The client would only need be able to print the reports that I have designed on my machine, not design their own. The reports would be saved as a file. The application will load the saved report and print it with provided data. I did see this article which answers the most part of my question. However, it does not include whether it covers loading saved report documents? Any additional related information for a commercial product newbie is gladly appreciated.

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C# Type conversion between two similar Datatable objects

- by Ali

I have .NET project with sync framework and two separate Datasets for MS SQL and Compact SQL. in my base class I have a generic DataTable object. in my derived classed I assign Typed DataTable to the generic object based on whether the application is operating online or offline: example: if (online) _dataTable = new MSSQLDataSet.Customer; else _dataTable = new CompactSQLDataSet.Customer; Now every where in my code i have to check and do a cast based on the current network mode like this: public void changeCustomerID(int ID) { if (online) (MSSQLDataSet.CustomerDataTable)_dataTable)[i].CustomerID = value; else (CompactMSSQLDataSet.CustomerDataTable)_dataTable)[i].CustomerID = value; } but I don't think this is very efficient and I believe it can be done in a smarter way to only use one line of code by dynamically getting the Type of _dataTable on the run time. my problem is at the design time, in order to acess datatable porperties such as "CustomerID" it has to be casted to either MSSQLDataSet.CustomerDataTable or CompactMSSQLDataSet.CustomerDataTable. Is there a way to have a function or a operator to convert the _datatable to its runtime type but still be able to use it's design time properties which are the same between the two types? something like: ((aType)_dataTable)[i].CustomerID = value; //or GetRuntimeType(_dataTable)[i].CustomerID = value;

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Self organizing layouts

- by user613326

Quite a while ago i was more in websites building then i am now. In my time there where huge debates about what to use; tables or pure CSS alternatives. I went out of the webdesigning, but now an old question re-surfaces. What i would like to create is a web page design that depending on screensize, would self organize the page into columns, so that for example on a PDA it would show 1 column On an old computer monitor, it would show 2 colomns, and on a widescreen laptop it would show 3 columns. I forgot how this was called and how it was done in the past, it had to do with XML and storing data seperate from design (if i remember well), perhaps these days better methods exist to do that, does this, anyone ring this a bell ? Also i note a lot is possible with Jquery and and brouwser depending webkits. But i need to make sure that it would run on all (modern) brouwsers : Iexplorer, Firefox, chrome And Jquery is nice too, but i am kinda woried that some day one of these brouwser vendors decides that jscript like java isnt enabled by default (or is that very unlikely ?)11 Perhaps someone can point me to a method that is the prefered way to do this.

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return Queryable<T> or List<T> in a Repository<T>

- by Danny Chen

Currently I'm building an windows application using sqlite. In the data base there is a table say User, and in my code there is a Repository<User> and a UserManager. I think it's a very common design. In the repository there is a List method: //Repository<User> class public List<User> List(where, orderby, topN parameters and etc) { //query and return } This brings a problem, if I want to do something complex in UserManager.cs: //UserManager.cs public List<User> ListUsersWithBankAccounts() { var userRep = new UserRepository(); var bankRep = new BankAccountRepository(); var result = //do something complex, say "I want the users live in NY //and have at least two bank accounts in the system } You can see, returning List<User> brings performance issue, becuase the query is executed earlier than expected. Now I need to change it to something like a IQueryable<T>: //Repository<User> class public TableQuery<User> List(where, orderby, topN parameters and etc) { //query and return } TableQuery<T> is part of the sqlite driver, which is almost equals to IQueryable<T> in EF, which provides a query and won't execute it immediately. But now the problem is: in UserManager.cs, it doesn't know what is a TableQuery<T>, I need to add new reference and import namespaces like using SQLite.Query in the business layer project. It really brings bad code feeling. Why should my business layer know the details of the database? why should the business layer know what's SQLite? What's the correct design then?

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Code Analysis Warning CA1004 with generic method

- by Vaccano

I have the following generic method: // Load an object from the disk public static T DeserializeObject<T>(String filename) where T : class { XmlSerializer xmlSerializer = new XmlSerializer(typeof(T)); try { TextReader textReader = new StreamReader(filename); var result = (T)xmlSerializer.Deserialize(textReader); textReader.Close(); return result; } catch (FileNotFoundException) { } return null; } When I compile I get the following warning: CA1004 : Microsoft.Design : Consider a design where 'MiscHelpers.DeserializeObject(string)' doesn't require explicit type parameter 'T' in any call to it. I have considered this and I don't know a way to do what it requests with out limiting the types that can be deserialized. I freely admit that I might be missing an easy way to fix this. But if I am not, then is my only recourse to suppress this warning? I have a clean project with no warnings or messages. I would like to keep it that way. I guess I am asking "why this is a warning?" At best this seems like it should be a message. And even that seems a bit much. Either it can or it can't be fixed. If it can't then you are just stuck with the warning with no recourse but suppressing it. Am I wrong?

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Better language or checking tool?

- by rwallace

This is primarily aimed at programmers who use unmanaged languages like C and C++ in preference to managed languages, forgoing some forms of error checking to obtain benefits like the ability to work in extremely resource constrained systems or the last increment of performance, though I would also be interested in answers from those who use managed languages. Which of the following would be of most value? A language that would optionally compile to CLR byte code or to machine code via C, and would provide things like optional array bounds checking, more support for memory management in environments where you can't use garbage collection, and faster compile times than typical C++ projects. (Think e.g. Ada or Eiffel with Python syntax.) A tool that would take existing C code and perform static analysis to look for things like potential null pointer dereferences and array overflows. (Think e.g. an open source equivalent to Coverity.) Something else I haven't thought of. Or put another way, when you're using C family languages, is the top of your wish list more expressiveness, better error checking or something else? The reason I'm asking is that I have a design and prototype parser for #1, and an outline design for #2, and I'm wondering which would be the better use of resources to work on after my current project is up and running; but I think the answers may be useful for other tools programmers also. (As usual with questions of this nature, if the answer you would give is already there, please upvote it.)

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What is better: Developing a Web project in MVC or N -Tier Architecture?

- by Starx

I have asked a similar question before and got an convincing answer as well? http://stackoverflow.com/questions/2843311/what-is-difference-of-developing-a-website-in-mvc-and-3-tier-or-n-tier-architectu Due to the conclusion of this question I started developing projects in N-tier Architecture. Just about an hour ago, I asked another question, about what is the best design pattern to create interface? There the most voted answer is suggesting me to use MVC architecture. http://stackoverflow.com/questions/2930300/what-is-the-best-desing-pattern-to-design-the-interface-of-an-webpage Now I am confused, First post suggested me that both are similar, just a difference that in N-tier, the tier are physically and logically separated and one layer has access to the one above and below it but not all the layers. I think ASP.net used 3 Tier architecture while developing applications or Web applications. Where as frameworks like Zend, Symphony they use MVC. I just want to stick to a pattern that is best suitable for WebProject Development? May be this is a very silly confusion? But if someone could clear this confusion, that would be very greatful?

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How can manage a FIFO-queue in an database with SQL?

- by Jonas

I have two tables in my database, one for In and one for Out. They have two columns, Quantity and Price. How can I write a SQL-query that selects the correct price? In example: If I have 3 items in for 75 and then 3 items in for 80. Then I have two out for 75, and the third out should be for 75 (X) and the fourth out should be for 80 (Y). How can I write the price query for X and Y? They should use the price from the third and forth row. In example, is there any way to SELECT the third row in the In-table? I can not use auto_increment as identifier for i.e. "third" row, because the tables will contain post for other items too. The rows will not be deleted, they will be saved for accountability reasons. SELECT Price FROM In WHERE ...? NEW database design: +----+ | In | +----+------+-------+ | Supply_ID | Price | +-----------+-------+ | 1 | 75 | | 1 | 75 | | 1 | 75 | | 2 | 80 | | 2 | 80 | +-----------+-------+ +-----+ | Out | +-----+-------+-------+ | Delivery_ID | Price | +-------------+-------+ | 1 | 75 | | 1 | 75 | | 2 | X | <- ? | 3 | Y | <- ? +-------------+-------+ OLD database design: +----+ | In | +----+------+----------+-------+ | Supply_ID | Quantity | Price | +-----------+----------+-------+ | 1 | 3 | 75 | | 2 | 3 | 80 | +-----------+----------+-------+ +-----+ | Out | +-----+-------+----------+-------+ | Delivery_ID | Quantity | Price | +-------------+----------+-------+ | 1 | 2 | 75 | | 2 | 1 | X | <- ? | 3 | 1 | Y | <- ? +-------------+----------+-------+

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SpringFramework3.0: How to create interceptors that only apply to requests that map to certain contr

- by Fusion2004

In it's simplest form, I want an interceptor that checks session data to see if a user is logged in, and if not redirects them to the login page. Obviously, I wouldn't want this interceptor to be used on say the welcome page or the login page itself. I've seen a design that uses a listing of every url to one of two interceptors, one doing nothing and the other being the actual interceptor you want implemented, but this design seems very clunky and limits the ease of extensibility of the application. It makes sense to me that there should be an annotation-based way of using interceptors, but this doesn't seem to exist. My friend has the idea of actually modifying the handler class so that during each request it checks the Controller it is mapping the request to for a new annotation we would create (ex @Interceptor("loginInterceptor") ). A major point of my thinking is the extensibility, because I'd like to later implement similar interceptors for role-based authentication and/or administration authentication. Does it sound like my friend's approach would work for this? Or what is a proper way of going about doing this?

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Data Warehouse: Modelling a future schedule

- by Pat

I'm creating a DW that will contain data on financial securities such as bonds and loans. These securities are associated with payment schedules. For example, a bond could pay quarterly, while a mortage would usually pay monthly (sometimes biweekly). The payment schedule is created when the security is traded and, in the majority of cases, will remain unchanged. However, the design would need to accomodate those cases where it does change. I'm currently attempting to model this data and I'm having difficulty coming up with a workable design. One of the most commonly queried fields is "next payment date". Users often want to know when a security will pay next. Therefore, I want to make it as easy as possible for them to get the next payment date and amount for each security. Also, users often run historical queries in which case they'd want the next payment date and amount as of a specific point in time. For example, they may want to look back at 1/31/09 and query the next payment dates (which would usually be in February 2009 for mortgages). It's also common that they want to query a security's entire payment schedule, which might consist of 360 records (30 year mortgage x 12 payments/year). Since the next payment date and amount would be changing each month or even biweekly, these fields wouldn't seem to fit into a slow-changing dimension very well. It would probably make more sense to use a fact table, but I'm unsure of how to model it. Any ideas would be greatly appreciated.

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How to use interfaces in exception handling

- by vikp

Hi, I'm working on the exception handling layer for my application. I have read few articles on interfaces and generics. I have used inheritance before quite a lot and I'm comfortable with in that area. I have a very brief design that I'm going to implement: public interface IMyExceptionLogger { public void LogException(); // Helper methods for writing into files,db, xml } I'm slightly confused what I should be doing next. public class FooClass: IMyExceptionLogger { // Fields // Constructors } Should I implement LogException() method within FooClass? If yes, than I'm struggling to see how I'm better of using an interface instead of the concrete class... I have a variety of classes that will make a use of that interface, but I don't want to write an implementation of that interface within each class. In the same time If I implement an interface in one class, and then use that class in different layers of the application I will be still using concrete classes instead of interfaces, which is a bad OO design... I hope this makes sense. Any feedback and suggestions are welcome. Please notice that I'm not interested in using net4log or its competitors because I'm doing this to learn. Thank you Edit: Wrote some more code. So I will implement variety of loggers with this interface, i.e. DBExceptionLogger, CSVExceptionLogger, XMLExceptionLogger etc. Than I will still end up with concrete classes that I will have to use in different layers of my application.

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