Search Results

Search found 41035 results on 1642 pages for 'object oriented design'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 404/1642 | < Previous Page | 400 401 402 403 404 405 406 407 408 409 410 411  | Next Page >

  • Database tables with dynamic information

    - by Tim Fennis
    I've googled this and found that it's almost impossible to create a database with dynamic collumns. I'll explain my problem first. I am making a webshop for a customer. It has multiple computer products for sale. CPU's HDD's RAM ect. All these products have different properties, a CPU has an FSB, RAM has a CAS latency. But this is very inconvenient because my orders table needs foreign keys to different tables which is impossible. An other option is to store all the product specific information in a varchar or blob field and let PHP figure it out. The problem with this solution is that the website needs a PC builder. A step-by-step guide to building your PC. So for instance if a customer decides he wants a new "i7 920" or whatever i want to be able to sellect all motherboards for socket 1366, which is impossible because all the data is stored in one field. I know it's possible to select all motherboards form the DB and let PHP figure out which ones are for socket 1366 but i was wondering, is there a better solution?

    Read the article

  • Best way to store this data?

    - by Malfist
    I have just been assigned to renovate an old website, and I get to move it from some old archaic system to drupal. The only problem is that it's a real-estate system and a lot of data is stored. Currently all the information is stored in a single table, an id represents the house and then everything else is key/value pairs. There are a possible 243 keys per estate, there are 23840 estates in the system. As you can imagine the system is slow and difficult to query. I don't think a table with 243 rows would be a very good idea, and probably worse than the current situation. I've done some investigating and here's what I've found out: Missing data does not indicate a 0 value, data is merged from two, unique sources/formats. Some guessing is involved. I have no control over the source of the data. There are 4 keys that are common to all estates, all values look like something that is commonly searched for and could be indexed There are 10 keys that are in the [90-100)% range 8 of these are information like who's selling it, and it's address. The other two seem to belong with the below range There are 80 keys that are in the [80-90)% range This range seems to mostly just list room types and how many the house has (e.g. bedrooms_possible, bathrooms, family_room_3rd, etc) This range also includes some minor information like school districts, one or two more pieces of data on the address. The 179 keys that are in the [0-80)% range include all sorts of miscellaneous information about the estate My best idea was a hybrid approach, create a table that stores important, common information and keep a smaller key/value table. How would you store this information?

    Read the article

  • Have 2 separate tables or an additional field in 1 table?

    - by hkansal
    Hello, I am making a small personal application regarding my trade of shares of various companies. The actions can be selling shares of a company or buying. Therefore, the details to be saved in both cases would be: Number of Shares Average Price Would it be better to use a separate tables for "buy" and "sell" or just use one table for "trade" and keep a field that demarcates "buy" from "sell"?

    Read the article

  • Static and default constuctor

    - by Ram
    A non static class can have static as well as default constructor at the same time. What is the difference between these two constructors? When shall I go for only static or static with default constructor?

    Read the article

  • correct technical term for this pattern

    - by Oliver A.
    sometimes I use a pattern which is very similar to the singleton pattern: There is one default instance which and a static get method to aces it. But you may create other instances and pass it as optional parameter and if you want to and you can even replace the default instance with a instance from a child class. So it is NO SINGLETON at all but it is used like one singleton in most cases. Anyone got an idea who to call something like this ? Maybe half*** singleton? domiton?

    Read the article

  • Parallel programming, are we not learning from history again?

    - by mezmo
    I started programming because I was a hardware guy that got bored, I thought the problems being solved in the software side of things were much more interesting than those in hardware. At that time, most of the electrical buses I dealt with were serial, some moving data as fast as 1.5 megabit!! ;) Over the years these evolved into parallel buses in order to speed communication up, after all, transferring 8/16/32/64, whatever bits at a time incredibly speeds up the transfer. Well, our ability to create and detect state changes got faster and faster, to the point where we could push data so fast that interference between parallel traces or cable wires made cleaning the signal too expensive to continue, and we still got reasonable performance from serial interfaces, heck some graphics interfaces are even happening over USB for a while now. I think I'm seeing a like trend in software now, our processors were getting faster and faster, so we got good at building "serial" software. Now we've hit a speed bump in raw processor speed, so we're adding cores, or "traces" to the mix, and spending a lot of time and effort on learning how to properly use those. But I'm also seeing what I feel are advances in things like optical switching and even quantum computing that could take us far more quickly that I was expecting back to the point where "serial programming" again makes the most sense. What are your thoughts?

    Read the article

  • Setting the type of a field in a superclass from a subclass (Java)

    - by Ibolit
    Hi. I am writing a project on Google App Engine, within it I have a number of abstract classes that I hope I will be able to use in my future projects, and a number of concrete classes inheriting from them. Among other abstract classes I have an abstract servlet that does user management, and I hava an abstract user. The AbstractUser has all the necessary fields and methods for storing it in the datastore and telling whether the user is registered with my service or not. It does not implement any project specific functionality. The abstract servlet that manages users, refers only to the methods declared in the AbstractUser class, which allows it to generate links for logging in, logging out and registering (for unregistered users). In order to implement the project-specific user functionality I need to subclass the Abstract user. The servlets I use in my project are all indirect descendants from that abstract user management servlet, and the user is a protected field in it, so the descendant servlets can use it as their own field. However, whenever i want to access any project specific method of the concrete user, i need to cast it to that type. i.e. (abstract user managing servlet) ... AbstractUser user = getUser(); ... abstract protected AbstractUser getUser(); (project-specific abstract servlet) @Override protected AbstractUser getUser() { return MyUserFactory.getUser(); } any other project specific servlet: int a = ((ConcreteUser) user).getA(); Well, what i'd like to do is to somehow make the type of “user” in the superclass depend on something in the project-specific abstract class. Is it at all possible? And i don't want to move all the user-management stuff into a project-specific layer, for i would like to have it for my future projects already written :) Thank you for your help.

    Read the article

  • What pattern is this? php

    - by user151841
    I have several classes that are basically interfaces to database rows. Since the class assumes that a row already exists ( __construct expects a field value ), there is a public static function that allows creation of the row and returns an instance of the class. Here's an example ( without the actual database inserts ): class selfStarter { public $type; public function __construct( $type ) { $this->type = $type; } public static function create( $type ) { if ( ! empty($type) ) { $starter = & new selfStarter($type); return $starter; } } } $obj1 = selfStarter::create( "apple" ); $obj2 = & new selfStarter( "banana" ); What is this pattern called?

    Read the article

  • How to store opening weekdays in a database

    - by JoaoPedro
    I have a group of checkboxes where the user selects some of the weekdays (the opening days of a store). How can I save the selected days? Should I save something like 0111111 (zero means closed on sunday) on the same field and split the result when reading the data? Or create a field for each day and store 0 or 1 on each (weird)?

    Read the article

  • guarantee child records either in one table or another, but not both?

    - by user151841
    I have a table with two child tables. For each record in the parent table, I want one and only one record in one of the child tables -- not one in each, not none. How to I define that? Here's the backstory. Feel free to criticize this implementation, but please answer the question above, because this isn't the only time I've encountered it: I have a database that holds data pertaining to user surveys. It was originally designed with one authentication method for starting a survey. Since then, requirements have changed, and now there are two different ways someone could sign on to start a survey. Originally I captured the authentication token in a column in the survey table. Since requirements changed, there are three other bits of data that I want to capture in authentication. So for each record in the survey table, I'm either going to have one token, or a set of three. All four of these are of different types, so my thought was, instead of having four columns where either one is going to be null, or three are going to be null ( or even worse, a bad mashup of either of those scenarios ), I would have two child tables, one for holding the single authentication token, the other for holding the three. Problem is, I don't know offhand how to define that in DDL. I'm using MySQL, so maybe there's a feature that MySQL doesn't implement that lets me do this.

    Read the article

  • C++: Conceptual problem in designing an intepreter

    - by sub
    I'm programming an interpreter for an experimental programming language (educational, fun,...) So far, everything went well (Tokenizer & Parser), but I'm getting a huge problem with some of the data structures in the part that actually runs the tokenized and parsed code. My programming language basically has only two types, int and string, and they are represented as C++ strings (std class) and ints Here is a short version of the data structure that I use to pass values around: enum DataType { Null, Int, String } class Symbol { public: string identifier; DataType type; string stringValue; int intValue; } I can't use union because string doesn't allow me to. This structure above is beginning to give me a headache. I have to scatter code like this everywhere in order to make it work, it is beginning to grow unmaintainable: if( mySymbol.type == Int ) { mySymbol.intValue = 1234; } else { mySymbol.stringValue = "abcde"; } I use the Symbol data structure for variables, return values for functions and general representation of values in the programming language. Is there any better way to solve this? I hope so!

    Read the article

  • is Payment table needed when you have an invoice table like this?

    - by EBAGHAKI
    this is my invoice table: Invoice Table: invoice_id creation_date due_date payment_date status enum('not paid','paid','expired') user_id total_price I wonder if it's Useful to have a payment table in order to record user payments for invoices. payment table can be like this: payment_id payment_date invoice_id price_paid status enum('successful', 'not successful')

    Read the article

  • Constructors + Dependency Injection

    - by Sunny
    If I am writing up a class with more than 1 constructor parameter like: class A{ public A(Dependency1 d1, Dependency2 d2, ...){} } I usually create a "argument holder"-type of class like: class AArgs{ public Dependency1 d1 { get; private set; } public Dependency2 d2 { get; private set; } ... } and then: class A{ public A(AArgs args){} } Typically, using a DI-container I can configure the constructor for dependencies & resolve them & so there is minimum impact when the constructors need to change. Is this considered an anti-pattern and/or any arguments against doing this?

    Read the article

  • Where do you find images and graphics for your softwares ?

    - by ereOn
    Hi, As a programmer, I'm sure some of you already experienced the same problem: You create a good software (free, open-source, or for friend-only diffusion, whatever) relying on good code and good ideas but since you're a programmer and not an image designer, your program looks just bad. While it seems pretty easy to find motivated developpers to join for free an open-source project, it seems quite hard to find a single free graphic designer. What free and good resources do you usually use for your programs/websites ? Do you have any cool tip that you're willing to share ?

    Read the article

  • How to set a value from another class

    - by Ram
    Its said that property should not be "Set" only and it should be "Get" as well. What should i do if I need to set value to a variable from some other class? The will keep changing so I cannot pass it through constructor. Shall I create a function for this as shown below? class A { public void SetValue() { b = new B(); b.SetTest(10); } } class B { int test; public void SetTest(int value) { test = value; } } What are the other alternatives?

    Read the article

  • One database or many?

    - by dsims
    I am developing a website that will manage data for multiple entities. No data is shared between entities, but they may be owned by the same customer. A customer may want to manage all their entities from a single "dashboard". So should I have one database for everything, or keep the data seperated into individual databases? Is there a best-practice? What are the positives/negatives for having a: database for the entire site (entity has a "customerID", data has "entityID") database for each customer (data has "entityID") database for each entity (relation of database to customer is outside of database) Multiple databases seems like it would have better performance (fewer rows and joins) but may eventually become a maintenance nightmare.

    Read the article

  • What is the point declaring variables at the end of class?

    - by serhio
    I saw multiple examples in MSDN that uses to declare the internal fields at the end of the class. What is the point? I find this a little embarrassing, because each time Visual Studio adds a method it adds it to the end of the class, so there is need every time to move it... class A { public A(){} // Methods, Properties, etc ... private string name; } class A { private string name; public A(){} // Methods, Properties, etc ... }

    Read the article

  • Interpreted languages: The higher-level the faster?

    - by immersion
    I have designed around 5 experimental languages and interpreters for them so far, for education, as a hobby and for fun. One thing I noticed: The assembly-like language featuring only subroutines and conditional jumps as structures was much slower than the high-level language featuring if, while and so on. I developed them both simultaneously and both were interpreted languages. I wrote the interpreters in C++ and I tried to optimize the code-execution part to be as fast as possible. My hypothesis: In almost all cases, performance of interpreted languages rises with their level (high/low). Am I basically right with this? (If not, why?)

    Read the article

  • One on One table relation - is it harmful to keep relation in both tables?

    - by EBAGHAKI
    I have 2 tables that their rows have one on one relation.. For you to understand the situation, suppose there is one table with user informations and there is another table that contains a very specific informations and each user can only link to one these specific kind of informations ( suppose second table as characters ) And that character can only assign to the user who grabs it, Is it against the rules of designing clean databases to hold the relation key in both tables? User Table: user_id, name, age, character_id Character Table: character_id, shape, user_id I have to do it for performance, how do you think about it?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 400 401 402 403 404 405 406 407 408 409 410 411  | Next Page >