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• Table with a lot of attributes

  - by Robert

  Hi, I'm planing to build some database project. One of the tables have a lot of attributes. My question is: What is better, to divide the the class into 2 separate tables or put all of them into one table. below is an example create table User { id, name, surname,... show_name, show_photos, ...) or create table User { id, name, surname,... ) create table UserPrivacy {usr_id, show_name, show_photos, ...) The performance i suppose is similar due to i can use index.

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• How extensible should code actually be?

  - by griegs

  I've just started a new job and one of the things my new boss talked to me about was code longevity. I've always coded to make my code infinently extensible and adaptable. I figured that if someone was going to change my code in the future then it should be easy to do. But I never really had a clear idea on how far into the future that should be. So my new boss told me not to bother coding for anything more that 3 years into the future and his reasoning was that technology changes, programs expire etc. At first I was kinda taken aback and thought he was a whack job but the longer I think about it the more I'm warming to the concept. Does anyone else have an opinion on how far into the future you should code to?

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• When is it better to use a method versus a property for a class definition?

  - by ccomet

  Partially related to an earlier question of mine, I have a system in which I have to store complex data as a string. Instead of parsing these strings as all kinds of separate objects, I just created one class that contains all of those objects, and it has some parser logic that will encode all properties into strings, or decode a string to get those objects. That's all fine and good. This question is not about the parser itself, but about where I should house the logic for the parser. Is it a better choice to put it as a property, or as a method? In the case of a property, say public string DataAsString, the get accessor would house the logic to encode all of the data into a string, while the set accessor would decode the input value and set all of the data in the class instance. It seems convenient because the input/output is indeed a string. In the case of a method, one method would be Encode(), which returns the encoded string. Then, either the constructor itself would house the logic for the decoding a string and require the string argument, or I write a Decode(string str) method which is called separately. In either case, it would be using a method instead of a property. So, is there a functional difference between these paths, in terms of the actual running of the code? Or are they basically equivalent and it then boils down to a choice of personal preference or which one looks better? And in that kind of question... which would look cleaner anyway?

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• Two different tables or just one with bool column?

  - by Aidas

  We have two tables: OriginalDocument and ProcessedDocument. In the first one we put an original, not processed document. After it's validated and processed (converted to our xml format and parsed), it's put into Document table. Processed document can be valid or invalid. Which makes more sense: have two different tables for valid and invalid documents or just have one with 'Valid' column? Some of the columns (~5-7) are irrelevant for invalid document. Storing both invalid and valid documents would also make Document table filled with 'NULL' columns (if document is invalid, information like document number, receiver can be unknown). What else should we consider and weigh, when making this decision?

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• Is Form validation and Business validation too much?

  - by Robert Cabri

  I've got this question about form validation and business validation. I see a lot of frameworks that use some sort of form validation library. You submit some values and the library validates the values from the form. If not ok it will show some errors on you screen. If all goes to plan the values will be set into domain objects. Here the values will be or, better said, should validated (again). Most likely the same validation in the validation library. I know 2 PHP frameworks having this kind of construction Zend/Kohana. When I look at programming and some principles like Don't Repeat Yourself (DRY) and single responsibility principle (SRP) this isn't a good way. As you can see it validates twice. Why not create domain objects that do the actual validation. Example: Form with username and email form is submitted. Values of the username field and the email field will be populated in 2 different Domain objects: Username and Email class Username {} class Email {} These objects validate their data and if not valid throw an exception. Do you agree? What do you think about this aproach? Is there a better way to implement validations? I'm confused about a lot of frameworks/developers handling this stuff. Are they all wrong or am I missing a point? Edit: I know there should also be client side kind of validation. This is a different ballgame in my Opinion. If You have some comments on this and a way to deal with this kind of stuff, please provide.

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• How to maintain an ordered table with Core Data (or SQL) with insertions/deletions?

  - by Jean-Denis Muys

  This question is in the context of Core Data, but if I am not mistaken, it applies equally well to a more general SQL case. I want to maintain an ordered table using Core Data, with the possibility for the user to: reorder rows insert new lines anywhere delete any existing line What's the best data model to do that? I can see two ways: 1) Model it as an array: I add an int position property to my entity 2) Model it as a linked list: I add two one-to-one relations, next and previous from my entity to itself 1) makes it easy to sort, but painful to insert or delete as you then have to update the position of all objects that come after 2) makes it easy to insert or delete, but very difficult to sort. In fact, I don't think I know how to express a Sort Descriptor (SQL ORDER BY clause) for that case. Now I can imagine a variation on 1): 3) add an int ordering property to the entity, but instead of having it count one-by-one, have it count 100 by 100 (for example). Then inserting is as simple as finding any number between the ordering of the previous and next existing objects. The expensive renumbering only has to occur when the 100 holes have been filled. Making that property a float rather than an int makes it even better: it's almost always possible to find a new float midway between two floats. Am I on the right track with solution 3), or is there something smarter?

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• Is there a recommended way to use the Observer pattern in MVP using GWT?

  - by Tomislav Nakic-Alfirevic

  I am thinking about implementing a user interface according to the MVP pattern using GWT, but have doubts about how to proceed. These are (some of) my goals: - the presenter knows nothing about the UI technology (i.e. uses nothing from com.google.*) - the view knows nothing about the model or the presenter - the model knows nothing of the view or the presenter (...obviously) I would place an interface between the view and the presenter and use the Observer pattern to decouple the two: the view generates events and the presenter gets notified. What confuses me is that java.util.Observer and java.util.Observable are not supported in GWT. This suggests that what I'm doing is not the recommended way to do it, as far as GWT is concerned, which leads me to my questions: what is the recommended way to implement MVP using GWT, specifically with the above goals in mind? How would you do it?

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• Coding without Grock. Is it wrong?

  - by OldCurmudgeon

  Should a professional programmer allow themselves to write code without completely understanding the requirements? In my 30+ years as a programmer I must have written many thousands of lines of code without completely understanding what is required of me at the time. In most cases the results were rubbish that should have been discarded. Every other industry that employs professionals has systems to root out such behavior. Ours does not. Is this right?

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• SEO with image link alt text vs standard text-based link

  - by Infiniti Fizz

  Hi, I'm currently developing a website and the main navigation is made up of image links because the font used for them isn't standard. My client's only worry is will this mess up search engine optimization? Can I just add alt text to the images like "link 1" or use the name attribute of the anchor tag? Or would it be better to just have the navigation as anchor tags with the names of the links in them like: <a href="...">link 1</a>? I'm new to SEO so really don't know which to suggest to him, Thanks for your time, InfinitiFizz

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• Refactor/rewrite code or continue?

  - by Dan

  I just completed a complex piece of code. It works to spec, it meets performance requirements etc etc but I feel a bit anxious about it and am considering rewriting and/or refactoring it. Should I do this (spending time that could otherwise be spent on features that users will actually notice)? The reasons I feel anxious about the code are: The class hierarchy is complex and not obvious Some classes don't have a well defined purpose (they do a number of unrelated things) Some classes use others internals (they're declared as friend classes) to bypass the layers of abstraction for performance, but I feel they break encapsulation by doing this Some classes leak implementation details (eg, I changed a map to a hash map earlier and found myself having to modify code in other source files to make the change work) My memory management/pooling system is kinda clunky and less-than transparent They look like excellent reasons to refactor and clean code, aiding future maintenance and extension, but could be quite time consuming. Also, I'll never be perfectly happy with any code I write anyway... So, what does stackoverflow think? Clean code or work on features?

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• Data Modeling of Entity with Attributes

  - by StackOverflowNewbie

  I'm storing some very basic information "data sources" coming into my application. These data sources can be in the form of a document (e.g. PDF, etc.), audio (e.g. MP3, etc.) or video (e.g. AVI, etc.). Say, for example, I am only interested in the filename of the data source. Thus, I have the following table: DataSource Id (PK) Filename For each data source, I also need to store some of its attributes. Example for a PDF would be "numbe of pages." Example for audio would be "bit rate." Example for video would be "duration." Each DataSource will have different requirements for the attributes that need to be stored. So, I have modeled "data source attribute" this way: DataSourceAttribute Id (PK) DataSourceId (FK) Name Value Thus, I would have records like these: DataSource->Id = 1 DataSource->Filename = 'mydoc.pdf' DataSource->Id = 2 DataSource->Filename = 'mysong.mp3' DataSource->Id = 3 DataSource->Filename = 'myvideo.avi' DataSourceAttribute->Id = 1 DataSourceAttribute->DataSourceId = 1 DataSourceAttribute->Name = 'TotalPages' DataSourceAttribute->Value = '10' DataSourceAttribute->Id = 2 DataSourceAttribute->DataSourceId = 2 DataSourceAttribute->Name = 'BitRate' DataSourceAttribute->Value '16' DataSourceAttribute->Id = 3 DataSourceAttribute->DataSourceId = 3 DataSourceAttribute->Name = 'Duration' DataSourceAttribute->Value = '1:32' My problem is that this doesn't seem to scale. For example, say I need to query for all the PDF documents along with thier total number of pages: Filename, TotalPages 'mydoc.pdf', '10' 'myotherdoc.pdf', '23' ... The JOINs needed to produce the above result is just too costly. How should I address this problem?

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• Android ignoring my setWidth() and setHeight()

  - by popoffka

  So, why does this code: package org.popoffka.apicross; import android.app.Activity; import android.os.Bundle; import android.widget.Button; public class Game extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Button testButton = new Button(this); testButton.setBackgroundResource(R.drawable.cell); testButton.setWidth(20); testButton.setHeight(20); setContentView(testButton); } } ...produce this thing: http://i42.tinypic.com/2hgdzme.png even though there's a setWidth(20) and setHeight(20) in the code? (R.drawable.cell is actually a 20x20 PNG image containing a white cell with a silver border)

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• Many-To-Many dimensional model

  - by Mevdiven

  Folks, I have a dimension table called DIM_FILE which holds information of the files we received from customers. Each file has detail records which constitutes my FACT table, CUST_DETAIL. In the main process, file is gone through several stages and each stage tags a status to it. Long in a short, I have many-to-many relationship. Any ideas around star schema dimensional modeling. A customer record only belong to a single file and a file can have multiple statuses. FACT ---- CustID FileID AmountDue DIM_FILE -------- FileID FileName DateReceived FILE_STATUS ----------- FileID StatusDateTime StatusCode

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• django models : How to have variable number of foreign keys in a model ?

  - by Rohit

  For instance, Model Resume contains variable number of Model Project 's, What should be my models and relationships between them to achieve this ? Thanks in advance.

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• Back Orders for ERP: data model references ?

  - by Patrick Honorez

  I have built an ERP using Sql Server as a back-end. These are the different types of Client documents (there are also Supplier Docs): Order -- impact: BO Delivery Note (also used for returns, with negative quantity) --impact: BO, Stock Invoice --impact: accounting only Credit Note --impact: accounting, BO I use a complex system of self joins (at detail level) to find out the quantities in each OrderDetail that still have a backorder (BO). It'd like to simplify this using a [group] field that could be used through all detail line related to an original order. There are many difficult things to trace: a Return of a product may be due to a defect and thus increase the BO, or it can be just a return, joined with a Credit Note, and then has no impact on BO. My question is: do you know of any real good reference (book, web) for this matter ?

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• Command Pattern : How to pass parameters to a command ?

  - by Romain Verdier

  My question is related to the command pattern, where we have the following abstraction (C# code) : public interface ICommand { Execute(); } Let's take a simple concrete command, which aims to delete an entity from our application. A Person instance, for example. I'll have a DeletePersonCommand, which implements ICommand. This command needs the Person to delete as a parameter, in order to delete it when Execute method is called. What is the best way to manage parametrized commands ? How to pass parameters to commands, before executing them ?

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• How to accomplish scrolling text on Twitter home page?

  - by Mike

  Hi, On the twitter home page (not logged in), there a scrolling text in the middle below the logo. How is this accomplished? It stops scrolling when mouseover and also has a popup dialog on relevant text. Thanks, Mike

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• Practical rules for premature optimization

  - by DougW

  It seems that the phrase "Premature Optimization" is the buzz-word of the day. For some reason, iphone programmers in particular seem to think of avoiding premature optimization as a pro-active goal, rather than the natural result of simply avoiding distraction. The problem is, the term is beginning to be applied more and more to cases that are completely inappropriate. For example, I've seen a growing number of people say not to worry about the complexity of an algorithm, because that's premature optimization (eg http://stackoverflow.com/questions/2190275/help-sorting-an-nsarray-across-two-properties-with-nssortdescriptor/2191720#2191720). Frankly, I think this is just laziness, and appalling to disciplined computer science. But it has occurred to me that maybe considering the complexity and performance of algorithms is going the way of assembly loop unrolling, and other optimization techniques that are now considered unnecessary. What do you think? Are we at the point now where deciding between an O(n^n) and O(n!) complexity algorithm is irrelevant? What about O(n) vs O(n*n)? What do you consider "premature optimization"? What practical rules do you use to consciously or unconsciously avoid it? This is a bit vague, but I'm curious to hear other peoples' opinions on the topic.

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• Updating multiple tables with LinqToSql in one unit of work

  - by zsharp

  Table 1: int ID-a(pk) Table 2: int ID-a(pk), int ID-b(pk) Table 3: int ID-b(pk), string C I have the data to insert into Table 1. But I do not have the ID-a, which is autogenerated. I have many string C to insert in Table 3. I am trying to insert row into Table 1, get the ID-a to insert in Table 2 along with the ID-b that is auto-Generated in Table 3 when I submit each string C, all in one submission to db. Right now I am calling dc.SubmitChanges twice in same call. Is it efficient to have to submit changes twice on same DataContext or can this be combined further?

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• Good recources on a problem decomposition?

  - by simple

  Could you please share some good books, blogs, sites on practical problem decomposition, thanks P.S. Please only practical ones not the scientific/theoretical resources.

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• Twitter Bootstrap Collapsible Navbar Duplicating

  - by sixeightzero

  I am working on a project using Twitter Bootstrap. One thing that I noticed is that my pages have duplicate navbars when they are defined as collapsible and the page is resized smaller. Here is the duplicate NavBar: Here is the normal width NavBar: Code: <!DOCTYPE html> <html lang="en"> <!--[if lt IE 7]> <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]--> <!--[if IE 7]> <html class="no-js lt-ie9 lt-ie8"> <![endif]--> <!--[if IE 8]> <html class="no-js lt-ie9"> <![endif]--> <!--[if gt IE 8]><!--> <html class="no-js"> <!--<![endif]--> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <title></title> <meta name="description" content=""> <meta name="viewport" content="width=device-width"> <link rel="stylesheet" href="/assets/css/bootstrap.css"> <style> body { padding-top: 60px; } </style> <link rel="stylesheet" href="/assets/css/bootstrap-responsive.min.css"> <link rel="stylesheet" href="/assets/css/main.css"> <script>window.jQuery || document.write('<script src="/assets/js/vendor/jquery-1.8.1.min.js"><\/script>')</script> <script src="/assets/js/vendor/modernizr-2.6.1-respond-1.1.0.min.js"></script> </head> <body class="dark"> <!--[if lt IE 9]> <p class="chromeframe">You are using an outdated browser. <a href="http://browsehappy.com/">Upgrade your browser today</a> or <a href="http://www.google.com/chromeframe/?redirect=true">install Google Chrome Frame</a> to better experience this site.</p> <![endif]--> <div class="navbar navbar-inverse navbar-fixed-top"> <div class="navbar-inner"> <div class="container"> <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse"> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </a> <a class="brand" href="#">Project name</a> <div class="nav-collapse collapse"> <ul class="nav"> <li class="active"><a href="#">Home</a></li> <li><a href="#about">About</a></li> <li><a href="#contact">Contact</a></li> <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a> <ul class="dropdown-menu"> <li><a href="#">Action</a></li> <li><a href="#">Another action</a></li> <li><a href="#">Something else here</a></li> <li class="divider"></li> <li class="nav-header">Nav header</li> <li><a href="#">Separated link</a></li> <li><a href="#">One more separated link</a></li> </ul> </li> </ul> </div><!--/.nav-collapse --> </div> </div> </div> Has anyone else run into this and have some pointers?

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• SQL efficiency argument, add a column or solvable by query?

  - by theTurk

  I am a recent college graduate and a new hire for software development. Things have been a little slow lately so I was given a db task. My db skills are limited to pet projects with Rails and Django. So, I was a little surprised with my latest task. I have been asked by my manager to subclass Person with a 'Parent' table and add a reference to their custodian in the Person table. This is to facilitate going from Parent to Form when the custodian, not the Parent, is the FormContact. Here is a simplified, mock structure of a sql-db I am working with. I would have drawn the relationship tables if I had access to Visio. We have a table 'Person' and we have a table 'Form'. There is a table, 'FormContact', that relates a Person to a Form, not all Persons are related to a Form. There is a relationship table for Person to Person relationships (Employer, Parent, etc.) I've asked, "Why this couldn't be handled by a query?" Response, Inefficient. (Really!?!) So, I ask, "Why not have a reference to the Form? That would be more efficient since you wouldn't be querying the FormContacts table with the reference from child/custodian." Response, this would essentially make the Parent is a FormContact. (Fair enough.) I went ahead an wrote a query to get from non-FormContact Parent to Form, and tested on the production server. The response time was instantaneous. *SOME_VALUE* is the Parent's fk ID. SELECT FormID FROM FormContact WHERE FormContact.ContactID IN (SELECT SourceContactID FROM ContactRelationship WHERE (ContactRelationship.RelatedContactID = *SOME_VALUE*) AND (ContactRelationship.Relationship = 'Parent')); If I am right, "This is an unnecessary change." What should I do, defend my position or should I concede to the managers request? If I am wrong. What is my error? Is there a better solution than the manager's?

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• Pattern/Matcher in Java?

  - by user1007059

  I have a certain text in Java, and I want to use pattern and matcher to extract something from it. This is my program: public String getItemsByType(String text, String start, String end) { String patternHolder; StringBuffer itemLines = new StringBuffer(); patternHolder = start + ".*" + end; Pattern pattern = Pattern.compile(patternHolder); Matcher matcher = pattern.matcher(text); while (matcher.find()) { itemLines.append(text.substring(matcher.start(), matcher.end()) + "\n"); } return itemLines.toString(); } This code works fully WHEN the searched text is on the same line, for instance: String text = "My name is John and I am 18 years Old"; getItemsByType(text, "My", "John"); immediately grabs the text "My name is John" out of the text. However, when my text looks like this: String text = "My name\nis John\nand I'm\n18 years\nold"; getItemsByType(text, "My", "John"); It doesn't grab anything, since "My" and "John" are on different lines. How do I solve this?

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• How do I write user-specific configuration into a rails app?

  - by dchua

  Hi all, What is the current practice like to write user-specific configuration settings into a rails application? For example, privacy settings in a social networking application. I know application-wide settings can be stored in a .yml file in config/ but what about users?

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• Returning large collections from WCF Serivce

  - by Nate Bross

  I'm trying to determine the best approach for building a WCF Service, and the area I'm struggling with most is returning lists of objects. The built-in maxMessageSize of 64k seems pretty high, and I really don't want to bump it up (quick googling finds 100s of places bumping the maxMessageSize up to multi-gigabyte range which seems foolish). But, when I'm returning a collection of objects (~150 items) I am exceeding the default 64k. I'm almost to the point of returning my own class which inherits IEnumerable and has properties for hasNext, hasPrevious and PageSize so that I can implement paging on the client side -- this seems like alot of code. The other option is to jackup the maxMessageSize and hope for the best, but that feels wrong. All other aspects of my service are working great, its just returning large collectiosn where I'm having issues. For background, there are two types of consumers of this service, UI applications which will be primarly web and/or wpf applications, and data processing applications, .NET console apps, and maybe some other non-UI apps. For the UI applications, I would like to keep them responsive and keep the messageSize low, on the console apps it doesn't matter as much as they are just pulling data down to do processing and push it back up to the service.

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