Search Results

Search found 17909 results on 717 pages for 'gui design'.

Page 253/717 | < Previous Page | 249 250 251 252 253 254 255 256 257 258 259 260  | Next Page >

  • Which Code Should Go Where in MVC Structure

    - by Oguz
    My problem is in somewhere between model and controller.Everything works perfect for me when I use MVC just for crud (create, read, update, delete).I have separate models for each database table .I access these models from controller , to crud them . For example , in contacts application,I have actions (create, read, update, delete) in controller(contact) to use model's (contact) methods (create, read, update, delete). The problem starts when I try to do something more complicated. There are some complex processes which I do not know where should I put them. For example , in registering user process. I can not just finish this process in user model because , I have to use other models too (sending mails , creating other records for user via other models) and do lots of complex validations via other models. For example , in some complex searching processes , I have to access lots of models (articles, videos, images etc.) Or, sometimes , I have to use apis to decide what I will do next or which database model I will use to record data So where is the place to do this complicated processes. I do not want to do them in controllers , Because sometimes I should use these processes in other controllers too. And I do not want to put these process in models because , I use models as database access layers .May be I am wrong,I want to know . Thank you for your answer .

    Read the article

  • How do I dynamically instantiate a class in javascript?

    - by Adam
    I'm starting out with classes in Javascript and have hit a wall. I've looked all over for a tutorial that goes a little further than simply how to construct a class (usually Animal) then extend the class and have a Method do something (Dog alert('Bark');). I have created a class that I want a user to be able to instantiate (is that the right word)? For example the first stage in my program is for the user to give the class a name, and then start to populate the various variables in the class. When they've done that they may do it again many times. So if: var className = new MyObject(); How do I dynamically create the name of the new object className and then refer to it later in the code?

    Read the article

  • Validation with State Pattern for Multi-Page Forms in ASP.NET

    - by philrabin
    I'm trying to implement the state pattern for a multi-page registration form. The data on each page will be accumulated and stored in a session object. Should validation (including service layer calls to the DB) occur on the page level or inside each state class? In other words, should the concrete implementation of IState be concerned with the validation or should it be given a fully populated and valid object? See "EmptyFormState" class below: namespace Example { public class Registrar { private readonly IState formEmptyState; private readonly IState baseInformationComplete; public RegistrarSessionData RegistrarSessionData { get; set;} public Registrar() { RegistrarSessionData = new RegistrarSessionData(); formEmptyState = new EmptyFormState(this); baseInformationComplete = new BasicInfoCompleteState(this); State = formEmptyState; } public IState State { get; set; } public void SubmitData(RegistrarSessionData data) { State.SubmitData(data); } public void ProceedToNextStep() { State.ProceedToNextStep(); } } //actual data stored in the session //to be populated by page public class RegistrarSessionData { public string FirstName { get; set; } public string LastName { get; set; } //will include values of all 4 forms } //State Interface public interface IState { void SubmitData(RegistrarSessionData data); void ProceedToNextStep(); } //Concrete implementation of IState //Beginning state - no data public class EmptyFormState : IState { private readonly Registrar registrar; public EmptyFormState(Registrar registrar) { this.registrar = registrar; } public void SubmitData(RegistrarSessionData data) { //Should Validation occur here? //Should each state object contain a validation class? (IValidator ?) //Should this throw an exception? } public void ProceedToNextStep() { registrar.State = new BasicInfoCompleteState(registrar); } } //Next step, will have 4 in total public class BasicInfoCompleteState : IState { private readonly Registrar registrar; public BasicInfoCompleteState(Registrar registrar) { this.registrar = registrar; } public void SubmitData(RegistrarSessionData data) { //etc } public void ProceedToNextStep() { //etc } } }

    Read the article

  • What are appropriate ways to represent relationships between people in a database table?

    - by Emilio
    I've got a table of people - an ID primary key and a name. In my application, people can have 0 or more real-world relationships with other people, so Jack might "work for" Jane and Tom might "replace" Tony and Bob might "be an employee of" Rob and Bob might also "be married to" Mary. What's the best way to represent this in the database? A many to many intersect table? A series of self joins? A relationship table with one row per relationship pair and type, where I insert records for the relationship in both directions?

    Read the article

  • What are practical guidelines for evaluating a language's "Turing Completeness"?

    - by AShelly
    I've read "what-is-turing-complete" and the wikipedia page, but I'm less interested in a formal proof than in the practical implications of being Turing Complete. What I'm actually trying to decide is if the toy language I've just designed could be used as a general-purpose language. I know I can prove it is if I can write a Turing machine with it. But I don't want to go through that exercise until I'm fairly certain of success. Is there a minimum set of features without which Turing Completeness is impossible? Is there a set of features which virtually guarantees completeness? (My guess is that conditional branching and a readable/writeable memory store will get me most of the way there) EDIT: I think I've gone off on a tangent by saying "Turing Complete". I'm trying to guess with reasonable confidence that a newly invented language with a certain feature set (or alternately, a VM with a certain instruction set) would be able to compute anything worth computing. I know proving you can building a Turing machine with it is one way, but not the only way. What I was hoping for was a set of guidelines like: "if it can do X,Y,and Z, it can probably do anything".

    Read the article

  • What situations does a Monostate pattern model?

    - by devoured elysium
    I know what both a Singleton or a Monostate are and how to implement them. Although I can see many uses for a Singleton, I can't imagine a situation where I would want to let the user create as many instances of my class although in reality only one really exists behind the scenes. Can anybody help me here? I know that for several reasons one should stay away from both patterns, but in theory, what kind of problems does the Monostate model? Thanks

    Read the article

  • Is there a Delphi dropdown notification component?

    - by Mason Wheeler
    You know how in Firefox, if something happens that requires your attention but isn't immediately urgent enough to require a modal dialog, it will drop down a little strip at the top of the tab with a question on it? I'd like to be able to put functionality like that in a Delphi app, but I don't know if there's a component for that. Does anyone know of one?

    Read the article

  • Style guide for database metadata naming

    - by Nulldevice
    We want to establish some database metadata naming rules in our new project. For example: tables are named as nouns in a plural form (courses, books, lessons) if present, an adjective goes before a noun in a table name and is separated by an underscore (red_books, new_lessons) table index column is always named "id" foreign key names are derived from a table name with suffix _id (book_id, red_book_id) so on Does someone know any guide like this?

    Read the article

  • Writing fortran robust and "modern" code

    - by Blklight
    In some scientific environments, you often cannot go without FORTRAN as most of the developers only know that idiom, and there is lot of legacy code and related experience. And frankly, there are not many other cross-platform options for high performance programming ( C++ would do the task, but the syntax, zero-starting arrays, and pointers are too much for most engineers ;-) ). I'm a C++ guy but I'm stuck with some F90 projects. So, let's assume a new project must use FORTRAN (F90), but I want to build the most modern software architecture out of it. while being compatible with most "recent" compilers (intel ifort, but also including sun/HP/IBM own compilers) So I'm thinking of imposing: global variable forbidden, no gotos, no jump labels, "implicit none", etc. "object-oriented programming" (modules with datatypes + related subroutines) modular/reusable functions, well documented, reusable libraries assertions/preconditions/invariants (implemented using preprocessor statements) unit tests for all (most) subroutines and "objects" an intense "debug mode" (#ifdef DEBUG) with more checks and all possible Intel compiler checks possible (array bounds, subroutine interfaces, etc.) uniform and enforced legible coding style, using code processing tools C stubs/wrappers for libpthread, libDL (and eventually GPU kernels, etc.) C/C++ implementation of utility functions (strings, file operations, sockets, memory alloc/dealloc reference counting for debug mode, etc.) ( This may all seem "evident" modern programming assumptions, but in a legacy fortran world, most of these are big changes in the typical programmer workflow ) The goal with all that is to have trustworthy, maintainable and modular code. Whereas, in typical fortran, modularity is often not a primary goal, and code is trustworthy only if the original developer was very clever, and the code was not changed since then ! (i'm a bit joking here, but not much) I searched around for references about object-oriented fortran, programming-by-contract (assertions/preconditions/etc.), and found only ugly and outdated documents, syntaxes and papers done by people with no large-scale project involvement, and dead projects. Any good URL, advice, reference paper/books on the subject?

    Read the article

  • Is ASP.NET MVC is really MVC? Or how to separate model from controller?

    - by Andrey
    Hi all, This question is a bit rhetorical. At some point i got a feeling that ASP.NET MVC is not that authentic implementation of MVC pattern. Or i didn't understood it. Consider following domain: electric bulb, switch and motion detector. They are connected together and when you enter the room motion detector switches on the bulb. If i want to represent them as MVC: switch is model, because it holds the state and contains logic bulb is view, because it presents the state of model to human motion detector is controller, because it converts user actions to generic model commands Switch has one private field (On/Off) as a State and two methods (PressOn, PressOff). If you call PressOn when it is Off it goes to On, if you call it again state doesn't change. Bulb can be replaced with buzzer, motion detector with timer or button, but the model still represent the same logic. Eventually system will have same behavior. This is how i understand classical MVC decomposition, please correct me if i am wrong. Now let's decompose it in ASP.Net MVC way. Bulb is still a view Controller will be switch + motion detector Model is some object that will just pass state to bulb. So the logic that defines behavior moves to controller. Question 1: Is my understanding of MVC and ASP.NET MVC correct? Question 2: If yes, do you agree that ASP.NET MVC is not 100% accurate implementation? And back to life. The final question is how to separate model from controller in case of ASP.NET MVC. There can be two extremes. Controller does basic stuff and call model to do all the logic. Another is controller does all the logic and model is just something like class with properties that is mapped to DB. Question 3: Where should i draw the line between this extremes? How to balance? Thanks, Andrey

    Read the article

  • Factory Method Implementation

    - by cedar715
    I was going through the 'Factory method' pages in SO and had come across this link. And this comment. The example looked as a variant and thought to implement in its original way: to defer instantiation to subclasses... Here is my attempt. Does the following code implements the Factory pattern of the example specified in the link? Please validate and suggest if this has to undergo any re-factoring. public class ScheduleTypeFactoryImpl implements ScheduleTypeFactory { @Override public IScheduleItem createLinearScheduleItem() { return new LinearScheduleItem(); } @Override public IScheduleItem createVODScheduleItem() { return new VODScheduleItem(); } } public class UseScheduleTypeFactory { public enum ScheduleTypeEnum { CableOnDemandScheduleTypeID, BroadbandScheduleTypeID, LinearCableScheduleTypeID, MobileLinearScheduleTypeID } public static IScheduleItem getScheduleItem(ScheduleTypeEnum scheduleType) { IScheduleItem scheduleItem = null; ScheduleTypeFactory scheduleTypeFactory = new ScheduleTypeFactoryImpl(); switch (scheduleType) { case CableOnDemandScheduleTypeID: scheduleItem = scheduleTypeFactory.createVODScheduleItem(); break; case BroadbandScheduleTypeID: scheduleItem = scheduleTypeFactory.createVODScheduleItem(); break; case LinearCableScheduleTypeID: scheduleItem = scheduleTypeFactory.createLinearScheduleItem(); break; case MobileLinearScheduleTypeID: scheduleItem = scheduleTypeFactory.createLinearScheduleItem(); break; default: break; } return scheduleItem; } }

    Read the article

  • Why Use PHP OOP over Basic Functions and When?

    - by Codex73
    There are some posts about this matter, but I didn't clearly get when to use Object Oriented coding and when to use programmatic functions in an include. Somebody also mentioned to me that OOP is very heavy to run, and makes more workload. Is this right? Lets say I have a big file with 50 functions, why will I want to call these in a class? and not by function_name(). Should I switch and create object which holds all of my functions? What will be the advantage or specific difference? What benefits does it bring to code OOP in php ? Modularity?

    Read the article

  • Business Objects - Containers or functional?

    - by Walter
    Where I work, we've gone back and forth on this subject a number of times and are looking for a sanity check. Here's the question: Should Business Objects be data containers (more like DTOs) or should they also contain logic that can perform some functionality on that object. Example - Take a customer object, it probably contains some common properties (Name, Id, etc), should that customer object also include functions (Save, Calc, etc.)? One line of reasoning says separate the object from the functionality (single responsibility principal) and put the functionality in a Business Logic layer or object. The other line of reasoning says, no, if I have a customer object I just want to call Customer.Save and be done with it. Why do I need to know about how to save a customer if I'm consuming the object? Our last two projects have had the objects separated from the functionality, but the debate has been raised again on a new project. Which makes more sense? EDIT These results are very similar to our debates. One vote to one side or another completely changes the direction. Does anyone else want to add their 2 cents? EDIT Eventhough the answer sampling is small, it appears that the majority believe that functionality in a business object is acceptable as long as it is simple but persistence is best placed in a separate class/layer. We'll give this a try. Thanks for everyone's input...

    Read the article

  • Need help to create database schema for wholesale online tee store

    - by techiepark
    Hi, I'm currently working on wholesale online t-shirt shop. I have done this for fixed quantity and price, and its working fine. Now i need to do this for variable quantity and price. Here is the reference link, like what i have to do. Basic tables i have created are - CREATE TABLE attribute ( attribute_id int(11) NOT NULL auto_increment, name varchar(100) NOT NULL, PRIMARY KEY (attribute_id) ); CREATE TABLE attribute_value ( attribute_value_id int(11) NOT NULL auto_increment, attribute_id int(11) NOT NULL, value varchar(100) NOT NULL, PRIMARY KEY (attribute_value_id), KEY idx_attribute_value_attribute_id (attribute_id) ); CREATE TABLE product ( product_id int(11) NOT NULL auto_increment, name varchar(100) NOT NULL, description varchar(1000) NOT NULL, price decimal(10,2) NOT NULL, image varchar(150) default NULL, thumbnail varchar(150) default NULL, PRIMARY KEY (product_id), FULLTEXT KEY idx_ft_product_name_description (name,description) ); CREATE TABLE product_attribute ( product_id int(11) NOT NULL, attribute_value_id int(11) NOT NULL, PRIMARY KEY (product_id,attribute_value_id) ); I'm not getting how to store the price based on variable quantity. Please help me to create product and its related tables. my requirement is same as above reference link.

    Read the article

  • Why is it bad to use boolean flags in databases? And what should be used instead?

    - by David Chanin
    I've been reading through some of guides on database optimization and best practices and a lot of them suggest not using boolean flags at all in the DB schema (ex http://forge.mysql.com/wiki/Top10SQLPerformanceTips). However, they never provide any reason as to why this is bad. Is it a peformance issue? is it hard to index or query properly? Furthermore, if boolean flags are bad, what should you use to store boolean values in a database? Is it better to store boolean flags as an integer and use a bitmask? This seems like it would be less readable.

    Read the article

  • Is it a good idea to cache data from web services into a database?

    - by Thierry Lam
    Let's assume that Stackoverflow offers web services where you can retrieve all the questions asked by a specific user. A request to get all question from user A can result in the following json output: { { "question": "What is rest?", "date_created": "20/02/2010", "votes": 1, }, { "question": "Which database to use for ...", "date_created": "20/07/2009", "votes": 5, }, } If I want to manipulate and present the data in any ways that I want, will it be wise to dump it in a local database? At some point, I will also want to retrieve all answers for each question and store them in a local database. The workflow that I'm thinking is: User logs in. Web services retrieve all questions asked by the logged in user, dump them in a local database. User wants all answers for a specific question, another web service does the retrieval and dump them in a local database. After user logs out, delete from the local database all questions and answers from that user.

    Read the article

  • Best practice for DAO pattern ?

    - by Tony
    I've seen a lot of codes use a service-dao pattern , I don't know the origin of this pattern . It force the front layer call service , then delegates some of the service task to dao. I want to ask : Does DAO layer do purely data access related task ? What about exception encapsulation ? Is there other pattern can be used to replace this ?

    Read the article

  • why is java.lang.Throwable a class?

    - by mdma
    In java adjectives ending in -able are interfaces Serializable, Comparable etc... So why is Throwable a class? Wouldn't exception handling be easier if Throwable were an interface? Obviously, changing it now is out the question. But could it be made abstract? Wouldn't that avoid the bad practice of throw new Throwable();

    Read the article

  • Data access pattern, combining push and pull?

    - by andlju
    I need some advice on what kind of pattern(s) I should use for pushing/pulling data into my application. I'm writing a rule-engine that needs to hold quite a large amount of data in-memory in order to be efficient enough. I have some rather conflicting requirements; It is not acceptable for the engine to always have to wait for a full pre-load of all data before it is functional. Only fetching and caching data on-demand will lead to the engine taking too long before it is running quickly enough. An external event can trigger the need for specific parts of the data to be reloaded. Basically, I think I need a combination of pushing and pulling data into the application. A simplified version of my current "pattern" looks like this (in psuedo-C# written in notepad): // This interface is implemented by all classes that needs the data interface IDataSubscriber { void RegisterData(Entity data); } // This interface is implemented by the data access class interface IDataProvider { void EnsureLoaded(Key dataKey); void RegisterSubscriber(IDataSubscriber subscriber); } class MyClassThatNeedsData : IDataSubscriber { IDataProvider _provider; MyClassThatNeedsData(IDataProvider provider) { _provider = provider; _provider.RegisterSubscriber(this); } public void RegisterData(Entity data) { // Save data for later StoreDataInCache(data); } void UseData(Key key) { // Make sure that the data has been stored in cache _provider.EnsureLoaded(key); Entity data = GetDataFromCache(key); } } class MyDataProvider : IDataProvider { List<IDataSubscriber> _subscribers; // Make sure that the data for key has been loaded to all subscribers public void EnsureLoaded(Key key) { if (HasKeyBeenMarkedAsLoaded(key)) return; PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } // Force all subscribers to get a new version of the data for key public void ForceReload(Key key) { PublishDataToSubscribers(key); MarkKeyAsLoaded(key); } void PublishDataToSubscribers(Key key) { Entity data = FetchDataFromStore(key); foreach(var subscriber in _subscribers) { subscriber.RegisterData(data); } } } // This class will be spun off on startup and should make sure that all data is // preloaded as quickly as possible class MyPreloadingThread { IDataProvider _provider; MyPreloadingThread(IDataProvider provider) { _provider = provider; } void RunInBackground() { IEnumerable<Key> allKeys = GetAllKeys(); foreach(var key in allKeys) { _provider.EnsureLoaded(key); } } } I have a feeling though that this is not necessarily the best way of doing this.. Just the fact that explaining it seems to take two pages feels like an indication.. Any ideas? Any patterns out there I should have a look at?

    Read the article

  • Sequence numbers best practice

    - by Abdullah Jibaly
    What's the best practice or well known methods to implement sequence numbers for business entities such as invoices, purchase orders, job numbers, etc? I want to be able to save the latest value in the database and be able to set it programatically. Is it OK to use a table for this purpose that has a SEQUENCE_NAME, SEQUENCE_NUMBER tuple? I know some databases have a first class sequence type but others (eg, MySQL) do not so it's not something I want to rely on. If a table is used to hold these sequences what is the right way to get and increment them in a synchronized fashion to ensure no data inconsistencies arise?

    Read the article

  • How strict to be when using Qt framework?

    - by toffeehoops
    I'm building a Qt application that needs to use libssh, a SSH client library. libssh (understandably) performs its own network connections, however Qt has its own infrastructure for network connections (QTcpSocket etc). Should I worry about these differences? Should I be trying to make libssh make network connections via QTcpSocket... Or if it works fine on the platforms I'm targeting, is that good enough?

    Read the article

  • Branchless memory manager?

    - by Richard Fabian
    Anyone thought about how to write a memory manager (in C++) that is completely branch free? I've written a pool, a stack, a queue, and a linked list (allocating from the pool), but I am wondering how plausible it is to write a branch free general memory manager. This is all to help make a really reusable framework for doing solid concurrent, in-order CPU, and cache friendly development. Edit: by branchless I mean without doing direct or indirect function calls, and without using ifs. I've been thinking that I can probably implement something that first changes the requested size to zero for false calls, but haven't really got much more than that. I feel that it's not impossible, but the other aspect of this exercise is then profiling it on said "unfriendly" processors to see if it's worth trying as hard as this to avoid branching.

    Read the article

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