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  • How to create a "facade" table?

    - by tputkonen
    A legacy database contains a join table which links tables table1 and table2, and contains just two foreign keys: TABLE_ORIG: table1_id table2_id In order to utilize this table using JPA I would need to create a surrogate primary key to the link table. However, the existing table must not be modified at all. I would like to create another table which would contain also a primary key in addition to the foreign keys: TABLE_NEW: id table1_id table2_id All changes to TABLE_ORIG should be reflected in TABLE_NEW, and vice versa. Is this doable in mysql?

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  • Best solution for a comment table for multiple content types

    - by KRTac
    I'm currently designing a comments table for a site I'm building. Users will be able to upload images, link videos and add audio files to the profile. Each of these types of content must be commentable. Now I'm wondering what's the best approach to this. My current options are: 1. to have one big comments table and a link tables for every content type (comments_videos, ...) with comment_id and _id. 2. to have comments separated by the type of content their for. So each type of content would have his own comments table with the comments for that type.

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  • Using implicit conversion as a substitute for multiple inheritance in .NET

    - by Daniel Plaisted
    I have a situation where I would like to have objects of a certain type be able to be used as two different types. If one of the "base" types was an interface this wouldn't be an issue, but in my case it is preferable that they both be concrete types. I am considering adding copies of the methods and properties of one of the base types to the derived type, and adding an implicit conversion from the derived type to that base type. Then users will be able treat the derived type as the base type by using the duplicated methods directly, by assigning it to a variable of the base type, or by passing it to a method that takes the base type. It seems like this solution will fit my needs well, but am I missing anything? Is there a situation where this won't work, or where it is likely to add confusion instead of simplicity when using the API?

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  • Performance Tricks for C# Logging

    - by Charles
    I am looking into C# logging and I do not want my log messages to spend any time processing if the message is below the logging threshold. The best I can see log4net does is a threshold check AFTER evaluating the log parameters. Example: _logger.Debug( "My complicated log message " + thisFunctionTakesALongTime() + " will take a long time" ) Even if the threshold is above Debug, thisFunctionTakesALongTime will still be evaluated. In log4net you are supposed to use _logger.isDebugEnabled so you end up with if( _logger.isDebugEnabled ) _logger.Debug( "Much faster" ) I want to know if there is a better solution for .net logging that does not involve a check each time I want to log. In C++ I am allowed to do LOG_DEBUG( "My complicated log message " + thisFunctionTakesALongTime() + " will take no time" ) since my LOG_DEBUG macro does the log level check itself. This frees me to have a 1 line log message throughout my app which I greatly prefer. Anyone know of a way to replicate this behavior in C#?

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  • Is it immoral to write crappy code even if readability and correctness is not a requirement?

    - by mafutrct
    There are cases when crappy (i.e. unreadable and buggy) code is not much of a problem. For instance, imagine you need to generate a big text file that mostly follows a simple pattern with a few very complex exceptions. What do you do? You quickly write a simple algorithm and insert the exceptional bits in the output manually to save 4 hours. The code is unreadable, and the output is flawed, but it's still the correct way since it is way faster. But let's get this straight: I hate bad code. I've had to read and work with code that caused my stomach to hurt. I care a lot about good code. And actually, I caught myself thinking that it is immoral to write bad code even though the dirty approach is sometimes superior. I was surprised by myself and found my idea to be very irrational. Did you ever experience this? Should I just get rid of this stupid idea and use the most efficient approach to coding?

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  • Anything similar to Hibernate in PHP?

    - by harigm
    I am a Java programmer and was working on a project using Hibernate and Struts for some time. Now For my new project, I am working on PHP and Mysql (learning PHP). Is there any technology which is similar to Hibernate for PHP? If yes, can anyone give me the link where I can understand and use it? Is there a POJO concept in PHP?

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  • Computation geometry: find where's the triangle after rotation, tranlastion or reflection in a mirro

    - by newba
    Hi, I have a small contest problem in which is given a set of points, in 2D, that form a triangle. This triangle may be subject to an arbitrary rotation, may be subject to an arbitrary translation (both in the 2D plane) and may be subject to a reflection on a mirror, but its dimensions were kept unchanged. Then, they give me a set of points in the plane, and I have to find 3 points that form my triangle after one or more of those geometric operations. Example: 5 15 8 5 20 10 6 5 17 5 20 20 5 10 5 15 20 15 10 I bet that have to apply some known algorithm, but I don't know which. The most common are: convex hull, sweep plane, triangulation, etc. Can someone give a tip? I don't need the code, only a push, please!

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  • How to apply Single Responsibility Principle to a service class

    - by Shekhar
    Hello Suppose we are designing a UserServiceImpl class which does CRUD(Create, Read, Update, and Delete) operations. In my view Create, Read, Update, and Delete are four reasons for a class to change. Does this class violates Single Responsibility Principle? If it violates, then should we have four classes like CreateUserServiceImpl, ReadUserServiceImpl, UpdateUserServiceImpl, and DeleteUserServiceImpl. Isn't it an overkill to have lots of classes? Thanks Shekhar

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  • How do I indicate success and failure with colour?

    - by Steve McLeod
    I need to make a Java component that turns the background a certain colour when a process passed, and another colour when the process failed. My first thought was: green for success, red for failure. But then I read that 10% of males can't differentiate between these two colours. What would be a better combination of colours? (For the nitpickers: yes, I know that colour alone doesn't suffice, that text, shape, and noise can also be used. Nevertheless I am asking about the appropriate use of colour.)

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  • What is the length of time to send a list of 200,000 integers from a client's browser to an internet

    - by indiehacker
    Over the connections that most people in the USA have in their homes, what is the approximate length of time to send a list of 200,000 integers from a client's browser to an internet sever (say Google app engine)? Does it change much if the data is sent from an iPhone? How does the length of time increase as the size of the integer list increases (say with a list of a million integers) ? Context: I wasn't sure if I should write code to do some simple computations and sorting of such lists for the browser in javascript or for the server in python, so I wanted to explore this issue of how long it takes to send the output data from a browser to a server over the web in order to help me decide where (client's browser or app engine server) is the best place for such computations to be processed.

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  • Are there old versions of Windows UX guidelines somewhere?

    - by Camilo Martin
    Since I've read Windows User Experience Interaction Guidelines (there's a PDF download avaliable) I've found it to be admirably self-deprecating, humbly pointing out their own horrible UI practices long scolded by Joel Spolsky. I'd like to know, however, what they had in mind while they made those mistakes. Is this (terrific) UX Guidelines document something new, or were there previous issues of such? If so, where can I find them? My prayers to Google yielded no leniency.

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  • Graph-structured databases and Php

    - by stagas
    I want to use a graph database using php. Can you point out some resources on where to get started? Is there any example code / tutorial out there? Or are there any other methods of storing data that relate to each other in totally random/abstract situations? - Very abstract example of the relations needed: John relates to Mary, both relate to School, John is Tall, Mary is Short, John has Blue Eyes, Mary has Green Eyes, query I want is which people are related to 'Short people that have Green Eyes and go to School' - answer John - Another example: TrackA -> ArtistA -> ArtistB -> AlbumA -----> [ label ] -> AlbumB -----> [ A ] -> TrackA:Remix -> Genre:House -> [ Album ] -----> [ label ] TrackB -> [ C ] [ B ] Example queries: Which Genre is TrackB closer to? answer: House - because it's related to Album C, which is related to TrackA and is related to Genre:House Get all Genre:House related albums of Label A : result: AlbumA, AlbumB - because they both have TrackA which is related to Genre:House - It is possible in MySQL but it would require a fixed set of attributes/columns for each item and a complex non-flexible query, instead I need every attribute to be an item by itself and instead of 'belonging' to something, to be 'related' to something.

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  • How to fluent-map this (using fluent nhibernate)?

    - by vikasde
    I have two tables in my database "Styles" and "BannedStyles". They have a reference via the ItemNo. Now styles can be banned per store. So if style x is banned at store Y then its very possible that its not banned at store Z or vice verse. What is the best way now to map this to a single entity? Should I be mapping this to a single entity? My Style entity looks like this: public class Style { public virtual int ItemNo { get; set;} public virtual string SKU { get; set; } public virtual string StyleName { get; set; } public virtual string Description { get; set; } public virtual Store Store { get; set; } public virtual bool IsEntireStyleBanned { get; set; } }

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  • Anticipate factorial overflow

    - by Flavius
    Hi I'm wondering how I could anticipate that the next iteration will generate an integer overflow while calculating the factorial F. Let's say that at each iteration I have an int I and the maximum value is MAX_INT. It sounds like a homework, I know. It's not. It's just me asking myself "stupid" questions.

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  • 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".

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  • How to record different authentication types (username / password vs token based) in audit log

    - by RM
    I have two types of users for my system, normal human users with a username / password, and delegation authorized accounts through OAuth (i.e. using a token identifier). The information that is stored for each is quite different, and are managed by different subsytems. They do however interact with the same tables / data within the system, so I need to maintain the audit trail regardless of whether human user, or token-based user modified the data. My solution at the moment is to have a table called something like AuditableIdentity, and then have the two types inheriting off that table (either in the single table, or as two seperate tables with 1 to 1 PK with AuditableIdentity. All operations would use the common AuditableIdentity PK for CreatedBy, ModifiedBy etc columns. There isn't any FK constraint on the audit columns, so any text can go in there, but I want an easy way to easily determine whether it was a human or system that made the change, and joining to the one AuditableIdentity table seems like a clean way to do that? Is there a best practice for this scenario? Is this an appropriate way of approaching the problem - or would you not bother with the common table and just rely on joins (to the two seperate un-related user / token tables) later to determine which user type matches which audit records?

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  • List of Lua derived VMs and Languages

    - by Shane Holloway
    Is there a compendium of virtual machines and languages derived or inspired by Lua? By derived, I mean usage beyond embedding and extending with modules. I'm wanting to research the Lua technology tree, and am looking for our combined knowledge of what already exists. Current List: Bright - A C-like Lua Derivative http://bluedino.net/luapix/Bright.pdf Agena - An Algol68/SQL like Lua Derivative http://agena.sourceforge.net/ LuaJIT - A (very impressive) JIT for Lua http://luajit.org MetaLua - An ML-style language extension http://metalua.luaforge.net/

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  • 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?

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  • 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.

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  • Images not responsive although in responsive container

    - by Darren Sweeney
    I have the following: <div id="hp_imgs"> <img src="/images/hp/1.jpg"> <img src="/images/hp/2.jpg"> <img src="/images/hp/3.jpg"> <img src="/images/hp/4.jpg"> <img src="/images/hp/5.jpg"> <img src="/images/hp/6.jpg"> <img src="/images/hp/7.jpg"> <img src="/images/hp/8.jpg"> </div> The images were sized when created to form a grid of sorts, so need to be in the order where they are. Consequently, when/if the page is resized I want the images to resize and stay where they are. Here's what I'm trying but images are simply staying the same size and not resizing: #hp_imgs { width:66%; float:left; } #hp_imgs img { float:left; margin:2px; border-radius:4px; display: block; max-width:100%; height:100%; } Is there a better/different way to achieve this? FIDDLE Here's a sample to play with: Fiddle

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  • 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?

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  • java Properties - to expose or not to expose?

    - by ring bearer
    This might be an age old problem and I am sure everyone has their own ways. Suppose I have some properties defined such as secret.user.id=user secret.password=password website.url=http://stackoverflow.com Suppose I have 100 different classes and places where I need to use these properties. Which one is good (1) I create a Util class that will load all properties and serve them using a key constant Such as : Util is a singleton that loads all properties and keeps up on getInstance() call. Util myUtil = Util.getInstance(); String user = myUtil.getConfigByKey(Constants.SECRET_USER_ID); String password = myUtil.getConfigByKey(Constants.SECRET_PASSWORD); .. //getConfigByKey() - inturns invokes properties.get(..) doSomething(user, password) So wherever I need these properties, I can do steps above. (2) I create a meaningful Class to represent these properties; say, ApplicationConfig and provide getters to get specific properties. So above code may look like: ApplicationConfig config = ApplicationConfig.getInstance(); doSomething(config.getSecretUserId(), config.getPassword()); //ApplicationConfig would have instance variables that are initialized during // getInstance() after loading from properties file. Note: The properties file as such will have only minor changes in the future. My personal choice is (2) - let me hear some comments?

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