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  • Good JDBC pattern

    - by Java Developer
    What is the good practice for database operation in Java application? Do you construct the DML syntax in the Java code and send the statements to DB engine for execution, or you just collect the parameters and then make a call to stored procedure with the parameters via java code? or neither because that's just not how to do it? can anyone give an example of a full database utility classes to do database operations in Java app? also what about the transaction manager? My assignment is to make database operation that is modular in Java. Thanks

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  • Patterns to deal with with functions that can have different kinds of results.

    - by KaptajnKold
    Suppose you have an method on an object that given the some input alters the objects state if the input validates according to some complex logic. Now suppose that when the input doesn't validate, it can be due to several different things, each of which we would like to be able to deal with in different ways. I'm sure many of you are thinking: That's what exceptions are for! I've thought of this also. But my reservation against using exceptions is that in some cases there is nothing exceptional about the input not validating and I really would like to avoid using exceptions to control what is really just in the expected flow of the program. If there were only one interpretation possible, I could simply choose to return a boolean value indicating whether or not the operation resulted in a state change or not and the respond appropriately when it did not. There is of course also the option to return a status code which the client can then choose to interpret or not. I don't like this much either because there is nothing semantic about status codes. The solution I have so far is to always check for each possible situation which I am able to handle before I call the method which then returns a boolean to inform the client if the object changed state. This leaves me the flexibility to handle as few or as many as the possible situations as I wish depending on the context I am in. It also has the benefit of making the method I am calling simpler to write. The drawback is that there is quite a lot of duplication in the client code wherever I call the method. Which of these solutions do you prefer and why? What other patterns do people use for providing meaningful feedback from functions? I know that some languages support multiple return values, and I if I had that option I would surely prefer it.

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  • C++ setting up "flags"

    - by sub
    Example: enum Flags { A, B, C, D }; class MyClass { std::string data; int foo; // Flags theFlags; (???) } How can I achieve that it is possible to set any number of the "flags" A,B,C and D in the enum above in an instance of MyClass? My goal would be something like this: if ( MyClassInst.IsFlagSet( A ) ) // ... MyClassInst.SetFlag( A ); //... Do I have to use some array or vector? If yes, how? Are enums a good idea in this case?

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  • database deign advice wanted: double data entry

    - by john
    hi, I'm designing a database for capturing clinical trial data. The data are entered twice by two persons, independently and the results must be matched. What are the best database tools to use to achieve the best results. Any one has similar experiences? Your helps are highly appreciated. thanks.

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  • When to Use Properties & When to Use Methods?

    - by DaveDev
    Hi Guys I was looking at the following line of code foreach (PropertyInfo prop in t.GetProperties()) and I noticed that tprovides a method to return the type's properties instead of a property like t.Properties This makes me wonder why sometimes people use properties to make a type's data avilable and other times there's a method provided? Is there some logic behind the decision? Thanks Dave

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  • What exactly is GRASP's Controller about?

    - by devoured elysium
    What is the idea behind Grasp's Controller pattern? My current interpretation is that sometimes you want to achieve something that needs to use a couple of classes but none of those classes could or has access to the information needed to do it, so you create a new class that does the job, having references to all the needed classes(this is, could be the information expert). Is this a correct view of what Grasp's Controller is about? Generally when googling or SO'ing controller, I just get results about MVC's (and whatnot) which are topics that I don't understand about, so I'd like answers that don't assume I know ASP.NET's MVC or something :( Thanks

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  • how to guarantee atomicity across two databases (the filesystem and your RDBMS)?

    - by Lock up
    i am working on a online file management project.In which we are storing references on the database(sql server) and files data on the on file system;.In which we are facing a problem of coordination between file system and database while we are uploading a file and also in case of deleting a file that first we create a reference in the data base or store files on file system;;the problem is that if create a reference in the database first and then storing a file on file system.bur while storing files on the file system any type of error occur.then reference for that file is created in the database but no file data on the file system;; please give me some solution how to deal with such situation;;i am badly in need of it;; and reason for that?

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  • How does ruby allow a method and a Class with the same name?

    - by Daniel Beardsley
    I happened to be working on a Singleton class in ruby and just remembered the way it works in factory_girl. They worked it out so you can use both the long way Factory.create(...) and the short way Factory(...) I thought about it and was curious to see how they made the class Factory also behave like a method. They simply used Factory twice like so: def Factory (args) ... end class Factory ... end My Question is: How does ruby accomplish this? and Is there danger in using this seemingly quirky pattern?

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  • Why are interfaces unusable in PHP?

    - by streetparade
    I mean an interface definition without defining the return type makes it unusable? This makes more Clear Interface run { public function getInteger(); } class MyString implements run { public function myNumber() { } public function getInteger() { return "Not a number"; } } In Java every Interface has a return type like Integer,String,Void I know that PHP is unfortunately a loosly typed Language but isnt there a Solution for that Problem? Is it Possible to defining a Interface with a Return type like Integer?

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  • What is the most challenging part of a project like MyLifeBits

    - by kennyzx
    I have made a small utility to keep track of my daily expenses, and my coffee consumption (I always want to quit coffee but never succeed), and of course, this kind of utility is quite simple, just involving an xml file and a few hundred lines of code to manipulate the file. Then I find this project MyLifeBits, it is very intesting, but I think it should require a lot of effort to achieve its goal- that is, to record everything about a person that can be digitally record. So I wonder, it is possible to write an advanced version of my own utility - but a tiny version of MyLifeBits, that can capture: Every webpage I've read, no matter what browser I am using, just download its contents for offline reading, Auto archive emails/documents/notes that I edited, Auto archive Codes that I run/written. Well, these are basically what I do on my PC. And the captured records can be searched easily. My question is, What do you think is the most challenging part? Interoperating with Visual Studio/Office/Lotes Notes/Web browsers is one thing, Database is another thing given that "everything" is record, Advanced programming patterns since it is not a "toy project"? And others that I have overlooked but can be very difficult to handle?

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  • How to get it working in O(n)?

    - by evermean
    I came across an interview task/question that really got me thinking ... so here it goes: You have an array A[N] of N numbers. You have to compose an array Output[N] such that Output[i] will be equal to multiplication of all the elements of A[N] except A[i]. For example Output[0] will be multiplication of A[1] to A[N-1] and Output[1] will be multiplication of A[0] and from A[2] to A[N-1]. Solve it without division operator and in O(n). I really tried to come up with a solution but I always end up with a complexity of O(n^2). Perhaps the is anyone smarter than me who can tell me an algorithm that works in O(n) or at least give me a hint...

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  • Organize address cache

    - by Orsol
    Hi, I need to organize cache in mySql database for address - coordinates. What is the best practice to store address? Do i need to compress address string or use it as is? edit: Ok, let's I reassert my question. How to store long (up to 512) string in database if I need to search by exactly this string in future.

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  • Desired features for C++

    - by bytepusher
    I am a full time C++ developer, and I really like the language. I think it is suited for almost any kind of application. Some people claim Java and C# are better suited for high level programming, but I'm not so sure about this. I have worked with all three languages, and when using C++, it happens only now and then I come across something that might be improved. What features would you like to see added to C++? I'm talking about big improvements, not details like typesafe enums.

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  • How to set value from other class

    - by Ram
    Its said that property should not be "Set" only and it should be "Get" as well. What should i do if I need to set value to a variable from some other class? The will keep changing so I cannot pass it through constructor. Shall I create a function for this as shown below? class A { public void SetValue() { b = new B(); b.SetTest(10); } } class B { int test; public void SetTest(int value) { test = value; } } What are the other alternatives?

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  • How to break up a table holding 100mil+ number of records?

    - by Chiao
    We're currently storing answers for 52 predefined questions for our clients in our matchmaking site. we have over 30million unique users summing up for worst case of a 52x30million rows. Of these 52 questions, 11 are required and always answered. Our previous solution was to open an answer table for each question. This solution distributed our answer rows for faster insert/delete/update. But it also caused us an unconventional programming such as dynamically opening a table each time a question is added/updated, or removing an answer table if it was to be destroyed permanently. We want to come up with a better solution for our third version but could't get very far yet. Any ideas to accomplish this in any other, perhaps a more conventional, way?

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