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  • how to handle exceptions/errors in php?

    - by fayer
    when using 3rd part libraries they tend to throw exceptions to the browser and hence kill the script. eg. if im using doctrine and insert a duplicate record to the database it will throw an exception. i wonder, what is best practice for handling these exceptions. should i always do a try...catch? but doesn't that mean that i will have try...catch all over the script and for every single function/class i use? Or is it just for debugging? i don't quite get the picture. Cause if a record already exists in a database, i want to tell the user "Record already exists". And if i code a library or a function, should i always use "throw new Expcetion($message, $code)" when i want to create an error? Please shed a light on how one should create/handle exceptions/errors. Thanks

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  • Buffering db inserts in multithreaded program

    - by Winter
    I have a system which breaks a large taks into small tasks using about 30 threads as a time. As each individual thread finishes it persists its calculated results to the database. What I want to achieve is to have each thread pass its results to a new persisance class that will perform a type of double buffering and data persistance while running in its own thread. For example, after 100 threads have moved their data to the buffer the persistance class then the persistance class swaps the buffers and persists all 100 entries to the database. This would allow utilization of prepared statements and thus cut way down on the I/O between the program and the database. Is there a pattern or good example of this type of multithreading double buffering?

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  • Fastest way to do a weighted tag search in SQL Server

    - by Hasan Khan
    My table is as follows ObjectID bigint Tag nvarchar(50) Weight float Type tinyint I want to get search for all objects that has tags 'big' or 'large' I want the objectid in order of sum of weights (so objects having both the tags will be on top) select objectid, row_number() over (order by sum(weight) desc) as rowid from tags where tag in ('big', 'large') and type=0 group by objectid the reason for row_number() is that i want paging over results. The query in its current form is very slow, takes a minute to execute over 16 million tags. What should I do to make it faster? I have a non clustered index (objectid, tag, type) Any suggestions?

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  • What is the MVC version of this code?

    - by Ian Boyd
    i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes. i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version? Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered: private void txtLastname_TextChanged(object sender, EventArgs e) { //Lastname mandatory. //Color pinkish if nothing entered. Greenish if entered. if (txtLastname.Text.Trim() == "") { //Lastname is required, color pinkish txtLastname.BackColor = ControlBad; } else { //Lastname entered, remove the coloring txtLastname.BackColor = ControlGood; } } Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field: private void txtFirstname_TextChanged(object sender, EventArgs e) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (txtFirstname.Text == "") { //Nothing there, hint it blue txtFirstname.BackColor = ControlRequired; } else if (txtFirstname.Text.Trim() == "") { //They entered spaces - bad user! txtFirstname.BackColor = ControlBad; } else { //Entered stuff, remove coloring txtFirstname.BackColor = SystemColors.Window; } } Example 3 The age is totally optional. If an age is entered, it better be valid: private void txtAge_TextChanged(object sender, EventArgs e) { //Age is optional, but if entered it better be valid int nAge = 0; if (Int32.TryParse(txtAge.Text, out nAge)) { //Valid integer entered if (nAge < 0) { //Negative age? i don't think so txtAge.BackColor = ControlBad; } else { //Valid age entered, remove coloring txtAge.BackColor = SystemColors.Window; } } else { //Whatever is in there: it's *not* a valid integer, if (txtAge.Text == "") { //Blank is okay txtAge.BackColor = SystemColors.Window; } else { //Not a valid age, bad user txtAge.BackColor = ControlBad; } } } Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help. The model is your data. The view shows data on screen. The controller is used to carry out the users actions And oranges taste orangy. Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC? private void txtFirstname_TextChanged(object sender, EventArgs e) { FirstnameTextChangedHandler(sender, e); } private void FirstnameTextChangedHandler(sender, e) { string firstname = GetFirstname(); Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname); SetFirstNameTextBoxColor(firstnameTextBoxColor); } private string GetFirstname() { return txtFirstname.Text; } private Color GetFirstnameTextBoxColor(string firstname) { //Firstname can be blank. //Hint them that they should *try* to get it with a bluish color. //If they do enter stuff: it better be not all spaces. if (firstname == "") { //Nothing there, hint it blue return GetControlRequiredColor(); } else if (firstname.Trim() == "") { //They entered spaces - bad user! return GetControlBadColor(); } else { //Entered stuff, remove coloring return GetControlDefaultColor(); } } private Color GetControlRequiredColor() { return ControlRequired; } private Color GetControlBadColor() { return ControlBad; } private Color GetControlGoodColor() { return ControlGood; } //am i doin it rite i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files. It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation? Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.

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  • What is the best practice for accessing Model using MVVM pattern

    - by Dzenand
    I have a database that communicates with webservices with my Model (own thread) and exposes Data Objects. My UI application consists of different Views and ViewModels and Custom Controls. I'm using ServiceProvider (IServiceProvider) to access the Model and route the events to the UI thread. Communication between the ViewModels is handeled by a Messenger. Is this way to go? I was also wondering what is the best way to strucutre the DataObjects At the moment i have the DataObjects that have a hierarchy structure but does not support INotifyProperty though the children list are of type of ObservableCollection. I have no possiblity to implement notifypropertychange on the properties. I was wondering the best way of making them MVVM friendly. Implementing a partial class and adding all the properties or commands that are necessary or wrapping all the DataObjects and keep the Model list and MVVM list in sync. All thoughts and ideas are appreciated.

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  • Best way to model Customer <--> Address

    - by Jen
    Every Customer has a physical address and an optional mailing address. What is your preferred way to model this? Option 1. Customer has foreign key to Address Customer (id, phys_address_id, mail_address_id) Address (id, street, city, etc.) Option 2. Customer has one-to-many relationship to Address, which contains a field to describe the address type Customer (id) Address (id, customer_id, address_type, street, city, etc.) Option 3. Address information is de-normalized and stored in Customer Customer (id, phys_street, phys_city, etc. mail_street, mail_city, etc.) One of my overriding goals is to simplify the object-relational mappings, so I'm leaning towards the first approach. What are your thoughts?

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  • 0/1 Knapsack with irrational weights

    - by user356106
    Consider the 0/1 knapsack problem. The standard Dynamic Programming algorithm applies only when the capacity as well as the weights to fill the knapsack with are integers/ rational numbers. What do you do when the capacity/weights are irrational? The issue is that we can't memoize like we do for integer weights because we may need potentially infinite decimal places for irrational weights - leading to an infinitely large number of columns for the Dynamic Programming Table . Is there any standard method for solving this? Any comments on the complexity of this problem? Any heuristics? What about associated recurrences like (for example): f(x)=1, for x< sqrt(2) f(x)=f(x-sqrt(2))+sqrt(3)

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  • How do you find the balance between Javascript (jQuery) and code behind in ASP.NET.

    - by PieterG
    Stackoverflow members, How do you currently find the balance between javascript and code behind. I have recently come across some extremely bad (in my eyes) legacy code that lends itself to chaos (someHugeJavafile.js) which contains a lot of the logic used in many of the pages. Let's say for example that you have a Form that you need to complete. 1. Personal Details 2. Address Information 3. Little bit more about yourself You don't want to overload the person with all the fields at once, so you decide to split it up into steps. Do you create separate pages for Personal Details, Address Information and a Little bit more about yourself. Do you create controls for each and hide and show them on a postback or using some update panel? Do you use jQuery and do some checking to ensure that the person has completed the required fields for the step and show the new "section" by using .show()? How do you usually find the balance?

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  • How many databases to support eCommerce?

    - by Terry Lorber
    I have a system with two databases, one that the customer-facing website uses, the second that is used by the "backroom" order-fulfillment system. I've been asked to run queries from the website to the backroom system. I'd rather not, it seems risky to allow web-based request to run unheeded on the internal system. Additionally, this means opening up routing in the firewall to allow external connections to the internal server. What's the best practice for eCommerce? Run the entire company off of one database? Or individual databases for each system, and middleware to connect them? Sometimes it might be necessary for the web application to pull date from the internal system, but not based on an HTTP request from the internet. I'm sure the best answer is "it depends!" So, if people have a rule of thumb for when to use middleware and when not to, I'd like to here it.

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  • What can you do in the ant Task.init() method?

    - by skiphoppy
    I'm developing a few custom ant tasks that all need to initialize the same objects. I wanted to initialize those object's in a common superclass that extends from Task, in the init() method. But I see from the lifecycle of an ant task that init() gets called before the tasks child elements and attributes are set. So all of the data I need for initializing those objects is unavailable during init(), if I am reading right. So, why is init() called at this point? What do you even know that you could use in init()? What could it be used for? (And is there some other method that I can rely on to be called before execute(), but after my data is available?)

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  • Application Code Redesign to reduce no. of Database Hits from Performance Perspective

    - by Rachel
    Scenario I want to parse a large CSV file and inserts data into the database, csv file has approximately 100K rows of data. Currently I am using fgetcsv to parse through the file row by row and insert data into Database and so right now I am hitting database for each line of data present in csv file so currently database hit count is 100K which is not good from performance point of view. Current Code: public function initiateInserts() { //Open Large CSV File(min 100K rows) for parsing. $this->fin = fopen($file,'r') or die('Cannot open file'); //Parsing Large CSV file to get data and initiate insertion into schema. while (($data=fgetcsv($this->fin,5000,";"))!==FALSE) { $query = "INSERT INTO dt_table (id, code, connectid, connectcode) VALUES (:id, :code, :connectid, :connectcode)"; $stmt = $this->prepare($query); // Then, for each line : bind the parameters $stmt->bindValue(':id', $data[0], PDO::PARAM_INT); $stmt->bindValue(':code', $data[1], PDO::PARAM_INT); $stmt->bindValue(':connectid', $data[2], PDO::PARAM_INT); $stmt->bindValue(':connectcode', $data[3], PDO::PARAM_INT); // Execute the statement $stmt->execute(); $this->checkForErrors($stmt); } } I am looking for a way wherein instead of hitting Database for every row of data, I can prepare the query and than hit it once and populate Database with the inserts. Any Suggestions !!! Note: This is the exact sample code that I am using but CSV file has more no. of field and not only id, code, connectid and connectcode but I wanted to make sure that I am able to explain the logic and so have used this sample code here. Thanks !!!

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  • Best datastructure for this relationship...

    - by Travis
    I have a question about database 'style'. I need a method of storing user accounts. Some users "own" other user accounts (sub-accounts). However not all user accounts are owned, just some. Is it best to represent this using a table structure like so... TABLE accounts ( ID ownerID -> ID name ) ...even though there will be some NULL values in the ownerID column for accounts that do not have an owner. Or would it be stylistically preferable to have two tables, like so. TABLE accounts ( ID name ) TABLE ownedAccounts ( accountID -> accounts(ID) ownerID -> accounts(ID) ) Thanks for the advice.

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  • What is the standard way to add an icon to a link with CSS?

    - by ewernli
    I'm used to use padding + background-image to place an icon next to a link. There are many example of this approach. Here is one from here: <a class="external" href="http://www.othersite.com/">link</a> a.external { padding-right: 15px; background: transparent url(images/external-link-icon.gif) no-repeat top right; } But most browser don't print background image, which is annoying. What is the standard to place icon next to links which is semantically correct and works in all cases? (I couldn't find an exact similar question. If there is one, just close this one as duplicate)

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  • Table with unequal rows in XUL layout

    - by Michael
    Trying to get something similar for Firefox extension using XUL. The most difficult part is the grid with unequal number of rows. I tried <grid> but it didn't work well. Also don't want to use HTML inside of XUL. Any ideas how to build such table?

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  • Would this constructor be acceptable practice?

    - by Robb
    Let's assume I have a c++ class that have properly implemented a copy constructor and an overloaded = operator. By properly implemented I mean they are working and perform a deep copy: Class1::Class1(const Class1 &class1) { // Perform copy } Class1& Class1::operator=(const Class1 *class1) { // perform copy return *this; } Now lets say I have this constructor as well: Class1::Class1(Class1 *class1) { *this = *class1; } My question is would the above constructor be acceptable practice? This is code that i've inherited and maintaining.

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  • Better alternative to autonumber primary keys

    - by Comrad_Durandal
    I am looking for a better primary key than the autonumber data type, namely for the reason that it's limited to a long integer, when I really just need the field to reflect a number or text string that will never ever repeat, no matter HOW many records are added or deleted from the table. The problem is I am not sure how to implement something like turning the current date and time into a hexadecimal string and using that as a unique field I can use as a primary key. Am I just being too paranoid about running out of space?

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  • Pattern for version-specific implementations of a Java class

    - by Mike Monkiewicz
    So here's my conundrum. I am programming a tool that needs to work on old versions of our application. I have the code to the application, but can not alter any of the classes. To pull information out of our database, I have a DTO of sorts that is populated by Hibernate. It consumes a data object for version 1.0 of our app, cleverly named DataObject. Below is the DTO class. public class MyDTO { private MyWrapperClass wrapper; public MyDTO(DataObject data) { wrapper = new MyWrapperClass(data); } } The DTO is instantiated through a Hibernate query as follows: select new com.foo.bar.MyDTO(t1.data) from mytable t1 Now, a little logic is needed on top of the data object, so I made a wrapper class for it. Note the DTO stores an instance of the wrapper class, not the original data object. public class MyWrapperClass { private DataObject data; public MyWrapperClass(DataObject data) { this.data = data; } public String doSomethingImportant() { ... version-specific logic ... } } This works well until I need to work on version 2.0 of our application. Now DataObject in the two versions are very similar, but not the same. This resulted in different sub classes of MyWrapperClass, which implement their own version-specific doSomethingImportant(). Still doing okay. But how does myDTO instantiate the appropriate version-specific MyWrapperClass? Hibernate is in turn instantiating MyDTO, so it's not like I can @Autowire a dependency in Spring. I would love to reuse MyDTO (and my dozens of other DTOs) for both versions of the tool, without having to duplicate the class. Don't repeat yourself, and all that. I'm sure there's a very simple pattern I'm missing that would help this. Any suggestions?

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  • Where do you put your dependencies?

    - by The All Foo
    If I use the dependency injection pattern to remove dependencies they end up some where else. For example, Snippet 1, or what I call Object Maker. I mean you have to instantiate your objects somewhere...so when you move dependency out of one object, you end up putting it another one. I see that this consolidates all my dependencies into one object. Is that the point, to reduce your dependencies so that they all reside in a single ( as close to as possible ) location? Snippet 1 - Object Maker <?php class ObjectMaker { public function makeSignUp() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignUpObject = new ControlSignUp(); $SignUpObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignUpObject; } public function makeSignIn() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignInObject = new ControlSignIn(); $SignInObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignInObject; } public function makeTweet( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $TweetObject = new ControlTweet(); $TweetObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $TweetObject; } public function makeBookmark( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $BookmarkObject = new ControlBookmark(); $BookmarkObject->setObjects($DatabaseObject,$TextObject,$MessageObject); return $BookmarkObject; } }

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  • What are the common patterns in web programming?

    - by lankerisms
    I have been trying to write my first big web app (more than one cgi file) and as I kept moving forward with the rough prototype, paralelly trying to predict more tasks, this is the todo that got accumulated (In no particular order). * Validations and input sanitizations * Object versioning (to avoid edit conflicts. I dont want hard locks) * Exception handling * memcache * xss and injection protections * javascript * html * ACLs * phonetics in search, match and find duplicates (for form validation) * Ajaxify!!! (I have snipped off the project specific items.) I know that each todo will be quite tied up to its project and technologies used. What I am wondering though, is if there is a pattern in your todo items as well as the sequence in which you experienced guys have come across them.

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  • C# Linq: Can you merge DataContexts?

    - by Andreas Grech
    Say I have one database, and this database has a set of tables that are general to all Clients and some tables that are specific to certain clients. Now what I have in mind is creating a primary DataContext that includes only the tables that are general to all the clients, and then create separate DataContexts that contain only the tables that are specific to the client. Is there a way to kind of "merge" DataContexts so that it becomes one context? So for Client A, I need one DataContext that includes both the general tables and also the tables for that specific client (retrieved from two different DataContexts) ? [Update] What I think I can do is, from the Partial Class of the DataContext instead of letting my DataContext inherit from DataContext I make it inherit from MyDataContext; that way, the tables from MyDataContext and the other DataContext will be available in one DataContext class. What do you think about this approach? Of course with something like this you can only merge two datacontexts at once though...

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  • Unexpected space between DIV elements

    - by jon
    my code for the php page displaying the divs <?php session_start(); require_once("classlib/mainspace.php"); if (isset($_SESSION['username'])==FALSE) { header("location:login.php"); } $user = new User($_SESSION['username']); ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="style/style.css" /> <title>SimpleTask - Home</title> </head> <body> <div id="main"> <div id="menu"> <div id="items"> <ul> <li><a href="home.php">home</a></li> <li>&bull;</li> <li><a href="projects.php">my projects</a></li> <li>&bull;</li> <li><a href="comments.php">my comments</a></li> </ul> </div> <div id="user"> <p>Welcome, <?php echo $user->GetRealName(); ?><br/><a href="editprofile.php">edit profile</a> &bull; <a href="logout.php">logout</a></p> </div> </div> <div id="content"> <h1>HOME</h1> </div> <div id="footer"> <p>footer text goes here here here here</p> </div> </div> </body> </html> and you can find my CSS here http://tasker.efficaxdevelopment.com/style/style.css and to view the live page go here http://tasker.efficaxdevelopment.com/login.php username:admin password:password

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