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  • IPhone geo tagging data (SQLite or CoreData)

    - by user267980
    Hi. I'm about to build an app that has a database of places that has a location (lon/lat) and i'm about to build the dataModel. Actualy the app is very simple and all i want is to be able to fetch all places around the user (say in a radius of 30miles). Is it better to user SQLite (is there any geo-spatial extension out there)? I'll have around 5000 places in the database and i'm wondering where i can ask a database without affecting performances.

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  • If I use a facade class with generic methods to access the JPA API, how should I provide additional processing for specific types?

    - by Shaun
    Let's say I'm making a fairly simple web application using JAVA EE specs (I've heard this is possible). In this app, I only have about 10 domain/data objects, and these are represented by JPA Entities. Architecturally, I would consider the JPA API to perform the role of a DAO. Of course, I don't want to use the EntityManager directly in my UI (JSF) and I need to manage transactions, so I delegate these tasks to the so-called service layer. More specifically, I would like to be able to handle these tasks in a single DataService class (often also called CrudService) with generic methods. See this article by Adam Bien for an example interface: http://www.adam-bien.com/roller/abien/entry/generic_crud_service_aka_dao My project differs from that article in that I can't use EJBs, so my service classes are essentially just named beans and I handle transactions manually. Regardless, what I want is a single interface for simple CRUD operations on my data objects because having a different class for each data type would lead to a lot of duplicate and/or unnecessary code. Ideally, my views would be able to use a method such as public <T> List<T> findAll(Class<T> type) { ... } to retrieve data. Using JSF, it might look something like this: <h:dataTable value="#{dataService.findAll(data.class)}" var="d"> ... </h:dataTable> Similarly, after validating forms, my controller could submit the data with a method such as: public <T> void add(T entity) { ... } Granted, you'd probably actually want to return something useful to the caller. In any case, this works well if your data can be treated as homogenous in this manner. Alas, it breaks down when you need to perform additional processing on certain objects before passing them on to JPA. For example, let's say I'm dealing with Books and Authors which have a many-to-many relationship. Each Book has a set of IDs referring to its authors, and each Author has a set of IDs referring to their books. Normally, JPA can manage this kind of relationship for you, but in some cases it can't (for example, the google app engine JPA provider doesn't support this). Thus, when I persist a new book for example, I may need to update the corresponding author entities. My question, then, is if there's an elegant way to handle this or if I should reconsider the sanity of my whole design. Here's a couple ways I see of dealing with it: The instanceof operator. I could use this to target certain classes when special processing is needed. Perhaps maintainability suffers and it isn't beautiful code, but if there's only 10 or so domain objects it can't be all that bad... could it? Make a different service for each entity type (ie, BookService and AuthorService). All services would inherit from a generic DataService base class and override methods if special processing is needed. At this point, you could probably also just call them DAOs instead. As always, I appreciate the help. Let me know if any clarifications are needed, as I left out many smaller details.

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  • how to design a db like Facebook where users can update their status and of the fb page as admin

    - by Harsha M V
    i am designing a database where users can update status messages of theirs and they can create pages groups like facebook fan page and post status like the admin of the page and not as a user. user(id, name..) group(id, name...) group_admin(group_id, user_id) this is my set up. Is this the way to do it. How to post under the group as an admin. will i need to make a check to every user if he is the admin or not ?

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  • Better alternative for PipedReader/PipedWriter?

    - by Esko Luontola
    I need to have a buffered char stream, into which I write in one thread and from which I read in another thread. Right now I'm using PipedReader and PipedWriter for it, but those classes cause a performance problem: PipedReader does a wait(1000) when its internal buffer is empty, which causes my application to lag visibly. Would there be some library which does the same thing as PipedReader/PipedWriter, but with better performance? Or will I have to implement my own wheels?

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  • SQL query construction - separate data in a column into two columns

    - by Tommy
    I have a column that contains links. The problem is that the titles of the links are in the same column, so it looks like this: linktitle|-|linkurl I want link title and linkurl in separate columns. I've created a new column for the urls, so I'm looking for a way to extract them and update the linkurl column with them. Is there any clever way to construct a query that does this?

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  • Comparing char for validation in C++

    - by Corey Starbird
    /* PROGRAM: Ch6_14.cpp Written by Corey Starbird This program calculates the balance owed to a hospital for a patient. Last modified: 10/28/13 */ #include <iostream> #include <fstream> #include <iomanip> #include <string> using namespace std; // Prototypes for In-patient and Out-patient functions. double stayTotal (int, double, double, double); // For In-patients double stayTotal (double, double); // For Out-patients int main() { char patientType; // In-patient (I or i) or Out-patient (O or o) double rate, // Daily rate for the In-patient stay servCharge, // Service charge for the stay medCharge, // Medication charge for the stay inTotal, // Total for the In-patient stay outTotal; // Total for the Out-patient stay int days; // Number of days for the In-patient stay // Find out if they were an In-patient or an Out-patient cout << "Welcome, please enter (I) for an In-patient or (O) for an Out-patient:" << endl; cin >> patientType; while (patientType != 'I' || 'i' || 'O' || 'o') { cout << "Invalid entry. Please enter either (I) for an In-patient or (O) for an Out-patient:" << endl; cin >> patientType; } cout << "FIN"; return 0; } Hey, brand new to C++ here. I am working on a project and I'm having trouble figuring out why my validation for patientTypeisn't working properly. I first had double quotes, but realized that would denote strings. I changed them to single quotes, my program will compile and run now, but the while loop runs no matter what I enter, I, i, O, o, or anything else. I don't know why the while loop isn't checking the condition, seeing that I did enter one of the characters in the condition, and move on to cout. Probably a simple mistake, but I thank you in advance.

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  • removing data from session

    - by sarah
    Hi All, i am using the following code to remove a attribute from session List l=(List) sess.getAttribute("allUserslist"); for(int ii=0;ii l1=(List) sess.getAttribute("allUserslist"); System.out.println("final size"+l1.size()); } te final size after removing is still one as before,where i am doing wrong ? }

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  • Population count of rightmost n integers

    - by Jason Baker
    I'm implementing Bagwell's Ideal Hash Trie in Haskell. To find an element in a sub-trie, he says to do the following: Finding the arc for a symbol s, requires ?nding its corresponding bit in the bit map and then counting the one bits below it in the map to compute an index into the ordered sub-trie. What is the best way to do this? It sounds like the most straightforward way of doing this is to select the bits below that bit and do a population count on the resulting number. Is there a faster or better way to do this?

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  • C# reads wrong registry data on 64-bit OS

    - by baal80
    I'm working on a 64-bit Windows and my applicaiton runs with elevated privileges. I have a problem with the following very simple piece of code: myKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run"); if (myKey != null) { string[] HKLMvaluenames = myKey.GetValueNames(); } But for some reason HKLMvaluenames array is populated with values from the following key: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run Is there a way around this problem?

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  • Display data from table in Ms.access into text box C#

    - by Sophorn
    I have a problem to ask you. I have a table in Ms.Access that contain: (FoodID, FoodName, Price) and in C# I have three text boxes (txtId, txtName, txtPrice) and a button (btnSearch). My question is that, In C# I just type FoodID in (txtId) and then click on button Search It'll display FoodName and Price ( from table access) in txtName and txtPrice by itself. What is the source code for this point? Please write the source code detail.(Please send it to my e-mail: [email protected]) I am looking forward to getting answer from you. Thanks you.

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  • MYSQL variables - SET @var

    - by Lizard
    I am attempting to create a mysql snippet that will analyse a table and remove duplicate entries (duplicates are based on two fields not entire record) I have the following code that works when I hard code the variables in the queries, but when I take them out and put them as variables I get mysql errors, below is the script SET @tblname = 'mytable'; SET @fieldname = 'myfield'; SET @concat1 = 'checkfield1'; SET @concat2 = 'checkfield2'; ALTER TABLE @tblname ADD `tmpcheck` VARCHAR( 255 ) NOT NULL; UPDATE @tblname SET `tmpcheck` = CONCAT(@concat1,'-',@concat2); CREATE TEMPORARY TABLE `tmp_table` ( `tmpfield` VARCHAR( 100 ) NOT NULL ) ENGINE = MYISAM ; INSERT INTO `tmp_table` (`tmpfield`) SELECT @fieldname FROM @tblname GROUP BY `tmpcheck` HAVING ( COUNT(`tmpcheck`) > 1 ); DELETE FROM @tblname WHERE @fieldname IN (SELECT `tmpfield` FROM `tmp_table`); ALTER TABLE @tblname DROP `tmpcheck`; I am getting the following error: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@tblname ADD `tmpcheck` VARCHAR( 255 ) NOT NULL' at line 1 Is this because I can't use a variable for a table name? What else could be wrong or how wopuld I get around this issue. Thanks in adavnce

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  • entering data in sql database through asp

    - by sushant
    pass=session("password") Set objIns=server.CreateObject("adodb.connection") objIns.Open session("Psrconnect") inspass="Insert into passwords(pass) values ('&pass&')" objIns.Execute(inspass) i dont know what should be the syntax to pass the value stored in the variable. with this syntax, the value entered in the database is &pass&. can anyone plz help me out?

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  • AS3/AIR: Managing Run-Time Image Data

    - by grey
    I'm developing a game with AS3 and AIR. I will have a large-ish quantity of images that I need to load for display elements. It would be nice not to embed all of the images that the game needs, thereby avoiding having them all in memory at once. That's okay in smaller projects, but doesn't make sense here. I'm curious about strategies for loading images during run time. Since all of the files are quite small and local ( in my current project ) loading them on request might be the best solution, but I'd like to hear what ideas people have for managing this. For bonus points, I'm also curious about solutions for loading images on-demand server-side as well.

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  • How to find missing alpha values in sets of data within same table in SQL

    - by Jeff
    I have a table of many values where one column has the WO Number, and another column has the Resource ID. I need to be able to find all the WO numbers that do not have a resource value of "RW". Here is an example of the typical information. I need to be able to know that work order 5678 does not have an "RW" Resource ID. WO Number - Resource ID 1234 - IN 1234 - WE 1234 - AS 1234 - RW 5678 - PR 5678 - WE 5678 - IN 5678 - AS

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  • C++ class is not recognizing string data type

    - by reallythecrash
    I'm working on a program from my C++ textbook, and this this the first time I've really run into trouble. I just can't seem to see what is wrong here. Visual Studio is telling me Error: identifier "string" is undefined. I separated the program into three files. A header file for the class specification, a .cpp file for the class implementation and the main program file. These are the instructions from my book: Write a class named Car that has the following member variables: year. An int that holds the car's model year. make. A string that holds the make of the car. speed. An int that holds the car's current speed. In addition, the class should have the following member functions. Constructor. The constructor should accept the car's year and make as arguments and assign these values to the object's year and make member variables. The constructor should initialize the speed member variable to 0. Accessors. Appropriate accessor functions should be created to allow values to be retrieved from an object's year, make and speed member variables. There are more instructions, but they are not necessary to get this part to work. Here is my source code: // File Car.h -- Car class specification file #ifndef CAR_H #define CAR_H class Car { private: int year; string make; int speed; public: Car(int, string); int getYear(); string getMake(); int getSpeed(); }; #endif // File Car.cpp -- Car class function implementation file #include "Car.h" // Default Constructor Car::Car(int inputYear, string inputMake) { year = inputYear; make = inputMake; speed = 0; } // Accessors int Car::getYear() { return year; } string Car::getMake() { return make; } int Car::getSpeed() { return speed; } // Main program #include <iostream> #include <string> #include "Car.h" using namespace std; int main() { } I haven't written anything in the main program yet, because I can't get the class to compile. I've only linked the header file to the main program. Thanks in advance to all who take the time to investigate this problem for me.

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  • [C++] Needed: A simple C++ container (stack, linked list) that is thread-safe for writing

    - by conradlee
    I am writing a multi-threaded program using OpenMP in C++. At one point my program forks into many threads, each of which need to add "jobs" to some container that keeps track of all added jobs. Each job can just be a pointer to some object. Basically, I just need the add pointers to some container from several threads at the same time. Is there a simple solution that performs well? After some googling, I found that STL containers are not thread-safe. Some stackoverflow threads address this question, but none form a consensus on a simple solution.

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  • [PHP] converting mysql data into array?

    - by Mahmoud
    i have an ajax script that check if the user name is available or not, but it keeps taking the newest user name and the rest are out $result = mysql_query("Select username from customer"); while ($row = mysql_fetch_array($result)){ $existing_users=array(''.$row['username'].','); } i know i am doing something worng

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  • getting data from xml tags that have : (colon in them)

    - by user3536228
    I am using AIR to build an application that will search and show the thumbnails from deviantART the request URL for getting resuts in form of RSS feed i get the following for simplicity i am showing the only code in which i have my question we can use this for tag trace(myxml.channel.item[0].title); but what to do for tags like media:content trace(myxml.channel.item[0].media:content); but it does not work The colons are confusing me

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  • how to order string logically

    - by just_name
    Q: I have the following case : set of letters (grades) A,A+,A-,B,B+,B- stored as strings in the database i wanna to order these grades logically from the small one to the big one ,, but this not what happen in real.. because these are strings the order is: A,A+,A- i wanna ASC A-,A,A+ DESC A+,A,A- i bind those grades in drop down list and i wanna these grades with this logical order in it.. is there any idea how to do something like this..

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  • Passing data between asp.net pages

    - by user204588
    Hello, I'm wondering the opinion of what is the best way to pass a lot of values between pages. I was thinking of either saving the values to a database, using context.Items[], or Session[]. I'm not sure about what is the best method. I'm passing probably around 40 variables.

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