Search Results

Search found 9610 results on 385 pages for 'common mistakes'.

Page 253/385 | < Previous Page | 249 250 251 252 253 254 255 256 257 258 259 260  | Next Page >

  • is it safe to refactor my django models?

    - by Johnd
    My model is similar to this. Is this ok or should I make the common base class abstract? What are the differcenes between this or makeing it abstract and not having an extra table? It seems odd that there is only one primary key now that I have factored stuff out. class Input(models.Model): details = models.CharField(max_length=1000) user = models.ForeignKey(User) pub_date = models.DateTimeField('date published') rating = models.IntegerField() def __unicode__(self): return self.details class Case(Input): title = models.CharField(max_length=200) views = models.IntegerField() class Argument(Input): case = models.ForeignKey(Case) side = models.BooleanField() is this ok to factor stuff out intpu Input? I noticed Cases and Arguments share a primary Key. like this: CREATE TABLE "cases_input" ( "id" integer NOT NULL PRIMARY KEY, "details" varchar(1000) NOT NULL, "user_id" integer NOT NULL REFERENCES "auth_user" ("id"), "pub_date" datetime NOT NULL, "rating" integer NOT NULL ) ; CREATE TABLE "cases_case" ( "input_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "cases_input" ("id"), "title" varchar(200) NOT NULL, "views" integer NOT NULL ) ; CREATE TABLE "cases_argument" ( "input_ptr_id" integer NOT NULL PRIMARY KEY REFERENCES "cases_input" ("id"), "case_id" integer NOT NULL REFERENCES "cases_case" ("input_ptr_id"), "side" bool NOT NULL )

    Read the article

  • Boost.Log - Multiple processes to one log file?

    - by Kevin
    Reading through the doc for Boost.Log, it explains how to "fan out" into multiple files/sinks pretty well from one application, and how to get multiple threads working together to log to one place, but is there any documentation on how to get multiple processes logging to a single log file? What I imagine is that every process would log to its own "private" log file, but in addition, any messages above a certain severity would also go to a "common" log file. Is this possible with Boost.Log? Is there some configuration of the sinks that makes this easy? I understand that I will likely have the same "timestamp out of order" problem described in the FAQ here, but that's OK, as long as the timestamps are correct I can work with that. This is all on one machine, so no remote filesystem problems either.

    Read the article

  • Using Remote Web Page to Initialize iPhone App

    - by Chris_K
    My iPhone app relies on a vendor's XML feed to provide data. But that feed is not locked down. The vendor could change the format of the XML at any time, although so far they've promised not to. Since I might want to tell my app to use a different URL for its data source, I'd like to set up a single "Command Central" Web page, on my own server, to direct the app to the correct data source. In other words, each time my app starts, in the background and unseen by the user, it would visit "http://www.myserver.com/iphoneapp_data_sources.xml" to retrieve the URL for retrieving data from my vendor. That way, if my vendor suddenly changes the exact URL or the XML feed that the app needs, I can update that Web page and ensure that all installations of the app are using the correct XML feed. Does anyone have any advice or examples showing this kind of approach? It seems as if this must be a common problem, but so far I haven't found a well-established design pattern that fits it.

    Read the article

  • ctrl-c does not copy text on a webpage

    - by aepheus
    I've come across this several times, ctrl-c randomly does not copy. I think it's caused by javascript or maybe some odd html syntax. I never spent the time to track down what caused it. Anyone know the typical/common causes of ctrl-c not working (to copy) on a website? Speaking from a developers standpoint. What do we developers end up doing to break ctrl-c? Just to clarify, I'm not interested in preventing copying. I'm trying to do the opposite, occasionally I find I've done something that is preventing ctrl-c from copying text, and that is not very user friendly on a text heavy site.

    Read the article

  • A problem with .NET 2.0 project, using a 3.0 DLL which implements WCF services.

    - by avance70
    I made a client for accessing my WCF services in one project, and all classes that work with services inherit from this class: public abstract class ServiceClient<TServiceClient> : IDisposable where TServiceClient : ICommunicationObject This class is where I do stuff like disposing, logging when the client was called, etc. some common stuff which all service classes would normally do. Everything worked fine, until I got the task to implement this on an old system. I got into a problem when I used this project (DLL) in an other project which cannot reference System.ServiceModel (since it's an old .NET 2.0 software that I still maintain, and upgrading it to 3.0 is out of the question). Here, if I omit where TServiceClient : ICommunicationObject then the project can build, but the ServiceClient cannot use, for example, client.Close() or client.State So, is my only solution to drop the where statement, and rewrite the service classes?

    Read the article

  • How do you handle multiple (overlapping) projects in trac?

    - by Oliver Giesen
    We are using trac and are really satisfied with it. However, out of the box, trac is best suited for single-project environments only. I'd be interested to hear about the various approaches people take to make it work with multiple projects nevertheless and their experiences with them. Are there any plugins to recommend? Any patches, tweaks or whatnots? Are you maybe even using an entirely different bug-tracking system that offers all of trac's functionality plus multi-project support? We recently started managing a second project ourselves which generally works okay but also has some drawbacks, especially where the two projects overlap because of common library code we wrote that is used in both projects. How do you handle this? (I'll attach our own current approach as an answer to this post.)

    Read the article

  • how to get a sub list from a list in ocaml

    - by romerun
    Hi, I'm looking at the List document. It seems the library does not provide a sublist function. I'm trying to get list of elements from i to j. Now I have to write it as: let rec sublist list i j = if i j then [] else (List.nth list i) :: (sublist list (i+1) j) which is quite concise but I'm questioning the efficiency of List.nth, because if it's O(n), I would rather have to write it in a less concise way. I'm wondering why didn't they provide List.sublist func, if List.nth is not O(1), because it's such a quite common operation..

    Read the article

  • Query with multiple IN-statements but without the cartesian product

    - by Janne
    How could I make this kind of query e.g. in MySQL SELECT * FROM Table t WHERE t.a IN (1,2,3) AND t.b IN (4,5,6) AND t.c IN (7,8,9) ... so that the result would contain only the three rows: t.a|t.b|t.c ---+---+--- 1 | 4 | 7 2 | 5 | 8 3 | 6 | 9 The above query of course returns all the combinations of the values in the IN clauses but I would like to get just the ones where the first elements of each tuple match, second elements of each tuple match and so on. Is there any efficient way to do this? By the way is there some common term for this kind of query or concept? I'm having hard time coming up with the question's title because I can't put this into words..

    Read the article

  • How to use GPS data like the double value returned by getLatitude()?

    - by Dan
    I have been searching quite a bit for an answer, but maybe I'm just not using the correct terminology. I am creating an app that will access a database to return a list of other users that are within a certain distance of the users location. I've never worked with this type of data, and I don't really know what the values mean. I'd like to do all the calculations on the backend with either MySQL or PHP. Currently, I am storing the latitude and longitude as doubles within the database. I can access them and store them, but I have no idea how I might be able to sort them based on distance. Perhaps I should be using a different type or some technique that is common in this area. TIA.

    Read the article

  • Will Visual Studio 2010 support HTML 5?

    - by Chris
    Since Visual Studio 2010 is slated for release in March of 2010 and HTML 5 is now starting to be used even more widely, I would like to know if Visual Studio will ship with HTML 5 templates, standard controls and support for the more common markup? A definition for support of HTML 5 would be that any new version of Visual Studio should have similar support for code-completion, validation and markup that is currently supported for HTML 4.01 and XHTML 1.0 and 1.1. Update From the Visual Web Develolper Team Blog: HTML 5 intellisense and validation schema for Visual Studio 2008 and Visual Web Developer is for downloading. Follow the instructions posted on the page to install the new scheme. Seems like the Visual Studio Team will be supporting HTML 5 after all.

    Read the article

  • What exactly does a self-describing type in .Net mean?

    - by tzup
    Given this MSDN article, we learn that the Common Type System in .Net has this classification of reference types: "Reference types can be self-describing types, pointer types, or interface types. The type of a reference type can be determined from values of self-describing types. Self-describing types are further split into arrays and class types." So an array, for instance, is a self-describing type because we can determine it's type from its values? How? Is that it, or is there more to this definition?

    Read the article

  • Method for demonstrating iPad application in online meetings

    - by competent_tech
    We have recently developed an iPad application and now need to start demonstrating it to customers and prospects as part of our overall product suite during webinars. As part of our Agile methodology, we also need to periodically review the application with key customers without having to distribute it since the application is not a standalone application and requires a connection to web services installed at each customer site. We have searched high and low for any solution that doesn't involve rooting the device but have been unable to find one. The most common suggestion seems to be to point a webcam at the device, but that comes across as very unprofessional. I know that there are VGA out adapters that can be plugged into the iPad and we have used these to present through a projector when the customer is physically present, but this is a relatively rare occurrence. Perhaps there are solutions that we are unaware of that can be used to send VGA output back into a desktop device for screen sharing?

    Read the article

  • Screen Resolution Question VS2008 - C++ CLI

    - by MrMcC
    Hi, I have a program that has a SIZE of 800x600. I want to make this program expand if it is maximized, so that all the elements(buttons, picturebox's) change size to fit the new ratio depending on the users windows screen resolution. The way I am thinking to approach this is to take the users screen resolution and manual change the size of everything, and do this for all common resolutions, if a user has some rare resolution, ill just make it so the maximize/minimize buttons are disabled. But this will be very very time consuming as there are lots of elements in the forms, and their are multiple forms..... Basically, is there a shortcut? Perhaps a built in feature or some kind of add in for VS2008. What are some methods to tackle this issue?

    Read the article

  • Fitting place names into map shapes

    - by Old Man
    I'm drawing shapes using GDI+ using a list of lat/lon floats, and I need to place the name of the place within the borders of the polygon. Simply centering the text in the bounding rectangle doesn't work for irregular shapes. I have the text and the font so I can get the size of the rectangle that the text will need to fit in, but at that point I'm stuck. This seems like a common problem that all mapping software solves, as well as the kind of thing you would find in an algorithm or computer graphics textbook. So, given a list of floats for a polygon and a rectangle, is there a way to get the best possible point to place the text, using: 1) GDI+; 2) SQL Server Geospatial; or 3) c# code (or c, pseudocode, etc)

    Read the article

  • Saving state between actions.

    - by Igor
    Hi all! I'd like to ask for a solution. For example we have a page. And I have a link to a another action from this page. I want to have an ability to save the values of entered data on the page. For instance I go to another page enter data and go back. Like the wizard. But the problem is that we can come to the action from different pages. And it need to save several data types. Is it understand? Any suggestions? I'd like to have common solution....

    Read the article

  • Confusion between JPA and Hibernate cascading

    - by Jay
    I'm using Hibernate 3.6 and have my code annotated (versus using hibernate mapping files). I ran into the known "problem" of using JPA cascading options that are not compatible with Hibernate's CascadeType (see this link for more info http://www.mkyong.com/hibernate/cascade-jpa-hibernate-annotation-common-mistake/). I was hoping to get a bit more clarification on the problem. I have some particular questions: 1) So @Cascade({CascadeType.SAVE_UPDATE}) works for saveOrUpdate(), but does it apply also if I use merge() or persist()? or do I have to use all three Hibernate CascadeTypes? 2) How do I decide whether to use JPA cascade options or the Hibernate @Cascade annotation instead? 2) There is a "bug" filed against this in Hibernate, but the developers apparently see this as a documentation issue, (I'm completely disagree with them), and I'm not seeing that it was addressed in said documentation. Anyone know why this is "working as designed" and not a bug in Hibernate's JPA implementation? Many thanks in advance.

    Read the article

  • Can XSD elements have more than one <annotation>?

    - by Scott
    I have a common data schema in XSD that is used by two different applications, A and B, each uses the data differently. I want to document the different business rules per application. Can I do this? <xs:complexType name="Account"> <xs:annotation app="A"> <xs:documentation> The Account entity must be used this way for app A </xs:documentation> </xs:annotation> <xs:annotation app="B"> <xs:documentation> The Account entity must be used this way for app B </xs:documentation> </xs:annotation> <xs:complexContent> ...

    Read the article

  • Preprocessor directive #ifndef for C/C++ code

    - by Leif Andersen
    In eclipse, whenever I create a new C++ class, or C header file, I get the following type of structure. Say I create header file example.h, I get this: /*Comments*/ #ifndef EXAMPLE_H_ #define EXAMPLE_H_ /* Place to put all of my definitions etc. */ #endif I think ifndef is saying that if EXAMPLE_H_ isn't defined, define it, which may be useful depending on what tool you are using to compile and link your project. However, I have two questions: Is this fairly common? I don't see it too often. And is it a good idea to use that rubric, or should you just jump right into defining your code. What is EXAMPLE_H_ exactly? Why not example.h, or just example? Is there anything special about that, or could is just be an artifact of how eclipse prefers to autobuild projects? Thank you for your help.

    Read the article

  • are Hierarchical SIngletons in Java possible?

    - by Zach H
    I've been toying with an interesting idea (No idea if I'll include it in any code, but it's fun to think about) Let's say we have a program that requires a large number of classes, all of a certain subclass. And those classes all need to be singletons. Now, we could write the singleton pattern for each of those classes, but it seems wasteful to write the same code over and over, and we already have a common base class. It would be really nice to create a getSingleton method of A that when called from a subclass, returns a singleton of the B class (cast to class A for simplicity) class A{ public A getSingleton(){ //Wizardry } } class B extends A{ } A blargh = B.getSingleton() A gish = B.getSingleton() if(A == B) System.out.println("It works!") It seems to me that the way to do this would be to recognize and call B's default constructor (assuming we don't need to pass anything in.) I know a little of the black magic of reflection in Java, but i'm not sure if this can be done. Anyone interested in puzzling over this?

    Read the article

  • How to handle added input data colums without having to maintain multiple versions of SSIS packages?

    - by GLFelger
    I’m writing to solicit ideas for a solution to an upcoming problem. The product that provides data to our ETL process currently has multiple versions. Our clients are all using some version of the product, but not all use the same version and they will not all be upgraded at the same time. As new versions of the product are rolled out, the most common change is to add new data columns. Columns being dropped or renamed may happen occasionally, but our main focus right now is how to handle new columns being added. The problem that we want to address is how to handle the data for clients who use an older version of the product. If we don’t account for the new columns in our SSIS packages, then the data in those columns for clients using an older product version will not be processed. What we want to avoid is having to maintain a separate version of the SSIS packages for each version of the product. Has anyone successfully implemented a solution for this situation?

    Read the article

  • What is the most "database independent" way of creating a variable length text field in a database

    - by Thibaut Colar
    I want to create a text field in the database, with no specific size (it will store text of length unknown in some case) - the particular text are serialized simple object (~ JSON) What is the most database independent way to do this : - a varchar with no size specified (don't think all db support this) - a 'text' field, this seems to be common, but I don't believe it's a standard - a blob or other object of that kind ? - a varchar of a a very large size (that's inefficient and wastes disk space probably) - Other ? I'm using JDBC, but I'd like to use something that is supported in most DB (oracle, mysql, postgresql, derby, HSQL, H2 etc...) Thanks.

    Read the article

  • Minimizing calls to database in rails

    - by ming yeow
    Hi guys, i am familiar with memcached and eager loading, but neither seems to solve the problem i am facing. My main performance lag comes from hundreds of data retrieval calls from the database. The tricky thing is that I do not know which set of users i need to retrieve until i have several steps of computation. I can refactor my code, but i was wondering how you experts handle this situation? I think it should be a fairly common situation def newsfeed - find out which users i need - retrieve those users via DB - find out which events happened for these users - for each of those events - retrieve new set of users - find out which groups are relevant - for each of those groups - retrieve new set of users - etc, etc end

    Read the article

  • Is this a valid, lazy, thread-safe Singleton implementation for C#?

    - by Matthew
    I implemented a Singleton pattern like this: public sealed class MyClass { ... public static MyClass Instance { get { return SingletonHolder.instance; } } ... static class SingletonHolder { public static MyClass instance = new MyClass (); } } From Googling around for C# Singleton implementations, it doesn't seem like this is a common way to do things in C#. I found one similar implementation, but the SingletonHolder class wasn't static, and included an explicit (empty) static constructor. Is this a valid, lazy, thread-safe way to implement the Singleton pattern? Or is there something I'm missing?

    Read the article

  • How can I write faster JavaScript?

    - by a paid nerd
    I'm writing an HTML5 canvas visualization. According to the Chrome Developer Tools profiler, 90% of the work is being done in (program), which I assume is the V8 interpreter at work calling functions and switching contexts and whatnot. Other than logic optimizations (e.g., only redrawing parts of the visualization that have changed), what can I do to optimize the CPU usage of my JavaScript? I'm willing to sacrifice some amount of readability and extensibility for performance. Is there a big list I'm missing because my Google skills suck? I have some ideas but I'm not sure if they're worth it: Limit function calls When possible, use arrays instead of objects and properties Use variables for math operation results as much as possible Cache common math operations such as Math.PI / 180 Use sin and cos approximation functions instead of Math.sin() and Math.cos() Reuse objects when passing around data instead of creating new ones Replace Math.abs() with ~~ Study jsperf.com until my eyes bleed Use a preprocessor on my JavaScript to do some of the above operations

    Read the article

  • Installing Java SDK on Linux.

    - by Negai
    Hi everyone, I'm currently trying to install Java SDK on my Debian 'Etch'. Even though the installation process has been described a number of times, but still I haven't found the information to solve the problem. Here is, what I'm getting: m@sanctuary:~/distr/java$ fakeroot make-jpkg jdk-6u20-linux-i586.bin Creating temporary directory: /tmp/make-jpkg.sqQPnaxiwl Loading plugins: blackdown-j2re.sh blackdown-j2sdk.sh common.sh ibm-j2re.sh ibm-j2sdk.sh j2re.sh j2sdk-doc.sh j2sdk.sh j2se.sh sun-j2re.sh sun-j2sdk-doc.sh sun-j2sdk.sh Detected Debian build architecture: i386 Detected Debian GNU type: i486-linux-gnu No matching plugin was found. Removing temporary directory: done Could anybody help me? Thanks in advance.

    Read the article

< Previous Page | 249 250 251 252 253 254 255 256 257 258 259 260  | Next Page >