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• Zend DB inserting relational data

  - by Wimbjorno

  I'm using the Zend Framework database relationships for a couple of weeks now. My first impression is pretty good, but I do have a question related to inserting related data into multiple tables. For a little test application I've related two tables with each other by using a fuse table. +---------------+ +---------------+ +---------------+ | Pages | | Fuse | | Prints | +---------------+ +---------------+ +---------------+ | pageid | | fuseid | | printid | | page_active | | fuse_page | | print_title | | page_author | | fuse_print | | print_content | | page_created | | fuse_locale | | ... | | ... | | ... | +---------------+ +---------------+ +---------------+ Above is an example of my DB architecture Now, my problem is how to insert related data to two separate tables and insert the two newly created ID's into the fuse table at the same time. If someone could could maybe explain or give me a topic related tutorial. I would appreciate it!

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• Where are good examples of Web applications built for skilled and intense use?

  - by ProfK

  I have spent most of my development career writing backend code, or front-end apps for used as daily business tools, by at least semi-skilled staff, e.g. order-tracking, sales capture, etc. That those I helped build peformed their tasks well is comfort enough, but I am still seeking excellence in the building of these kind of apps, versus the more trendy emphasis on slow and sensual interpersonal relationships with the UI. Can anyone recommend reading on this type of application (LOB?) on the web today? Any available examples to study?

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• Sqlalchemy: Many to Many relationship error

  - by 1001010101

  Dear everyone, I am following the Many to many relationship described on http://www.sqlalchemy.org/docs/mappers.html#many-to-many #This is actually a VIEW tb_mapping_uGroups_uProducts = Table( 'mapping_uGroups_uProducts', metadata, Column('upID', Integer, ForeignKey('uProductsInfo.upID')), Column('ugID', Integer, ForeignKey('uGroupsInfo.ugID')) ) tb_uProducts = Table( 'uProductsInfo', metadata, Column('upID', Integer, primary_key=True) ) mapper( UnifiedProduct, tb_uProducts) tb_uGroupsInfo = Table( 'uGroupsInfo', metadata, Column('ugID', Integer, primary_key=True) ) mapper( UnifiedGroup, tb_uGroupsInfo, properties={ 'unifiedProducts': relation(UnifiedProduct, secondary=tb_mapping_uGroups_uProducts, backref="unifiedGroups") }) where the relationship between uProduct and uGroup are N:M. When I run the following sess.query(UnifiedProduct).join(UnifiedGroup).distinct()[:10] I am getting the error: sqlalchemy.exc.ArgumentError: Can't find any foreign key relationships between 'uProductsInfo' and 'uGroupsInfo' What am I doing wrong?

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• Is there a generic open-source reporting system out there?

  - by syntactico

  I recently started a position at a new company, and one of the first projects they want is an internal reporting system that points at database A, B, C and reports various metrics/statistics/predictions. Basically, the same thing I've done or worked on and every company I've ever been hired by. Since this gets a bit boring after a while, I was wondering if there already exists some sort of open-source package that accomplishes this goal. Ideally, it would work with multiple databases out-of-box (PostgreSQL, MySQL, MSSQL, Oracle minimally), determine relationships between tables (either automatically from their schemas, or allow you to manually set them up after pooling all the tables), allow you to create reports based on a subset of tables, customizing what data you wanted to be displayed/calculated (I suppose this would be challenging since you've no idea what every audience wants, and would need to make this flexible) I'm debating making something like this in my spare time if one does not already exist. Just curious.

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• Tool to view/plan keyboard shortcuts?

  - by Willfulwizard

  I'm curious if there are any tools available* that will help me map out keyboard shortcuts for the application I'm working on? Being able to see what combinations are in use, the relationships between normal, ctrl, shift, and alt combinations, and especially what combinations are NOT in use, would be wonderfully helpful. Please forgive me if I am missing an obvious solution, but I've had no luck searching for such a tool myself, due to every application in existence having its own keyboard shortcuts, and all of those being listed on the web. Thanks! *Naturally, I'd prefer free/cheap, but it can't hurt to hear about any expensive options.

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• Rails 2.3.5: How does one add an error when it doesn't make sense to put it in a validation?

  - by randombits

  I recently was trying to add errors.add_to_base code in the middle of some model logic and was wondering why it wasn't showing up in my view that was iterating over all errors. I then ran across this e-mail which explains why: http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/e045ec1dead1ff06?pli=1 The question is then, how does one add errors with add_to_base if it doesn't make sense to put them into a validate method? I have some complex logic. The model needs to talk to a has_many relationship which has its own relationships that go through a myriad of conditionals to figure out if a request makes sense. It's nothing that can be tied to a validate method easily. How does one add errors then accordingly?

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• transform file/directory structure into 'tree' in javascript

  - by dave

  I have an array of objects that looks like this: [{ name: 'test', size: 0, type: 'directory', path: '/storage/test' }, { name: 'asdf', size: 170, type: 'directory', path: '/storage/test/asdf' }, { name: '2.txt', size: 0, type: 'file', path: '/storage/test/asdf/2.txt' }] There could be any number of arbitrary path's, this is the result of iterating through files and folders within a directory. What I'm trying to do is determine the 'root' node of these. Ultimately, this will be stored in mongodb and use materialized path to determine it's relationships. In this example, /storage/test is a root with no parent. /storage/test/asdf has the parent of /storage/test which is the parent to /storage/test/asdf/2.txt. My question is, how would you go about iterating through this array, to determine the parent's and associated children? Any help in the right direction would be great! Thank you

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• Is there a tool that will show diagrams of my SQL database in real-time?

  - by Rising Star

  I've created some diagrams of SQL tables using the "Reverse Engineer" feature of Microsoft Office Visio. I like being able to visualize my relational databases in this manner. However, what I get is just a static document that I can print, e-mail to colleagues, and click widgets on. Earlier this year, I saw at a demo that the new version of Visual Studio 2010 has a new feature called the "Architect Explorer", which allows developers to view relationships among .net classes on the fly. It has many features for filtering the data that the developer is interested in. It would be really awesome if I could visually browse my tables and stored procedures and see what is related to what by primary key, foreign key, and referenced in stored procedures. I realize that I'm talking about two entirely different technologies and it's not a perfect analogy, but is there some similar tool that would allow me to visualize tables in my SQL database?

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• Complex class using PHP soapserver mapclass

  - by user559343

  Hi all, I need to create a server for processing SOAP requests. I have the wsdl and xml specifications, but I have a doubt: the xml elements are pretty complex, they are not simple type, but they have parent/child relationships (e.g. I have a Book class with an author subclass). How can I map this to PHP classes? In this example, should I create an author class i.e.: class Author { public $name; public $surname; } and then class Book { public $author; } will $author be a class of type Author? Or a typed array? Any help will be appreciated Thanks and happy new year!

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• Custom DDL Templates for Visual Studio 2010

  - by Stacey

  I was wondering if anyone knows of some good community distributed custom DDL templates for Entity Framework 4.0. The default DDL to SQL10 Works well enough, but we're looking to do some customization to the naming convention that it just isn't offering us. I'm not really finding many samples out there of people doing this, so I was hoping someone might know of a resource I'm overlooking (perhaps I am searching for it wrong, or misunderstanding how the whole process works) Specifically we're wanting to change up how it writes out fields from relationships. For instance, the default template puts in.. tablename_propertyendpoint_propertyname. We're wanting to find tune this to our naming scheme a little more. And none of us can quite figure out where in the .tt files it is doing this exact behavior.

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• iOS Development: Can I store an array of integers in a Core Data object without creating a new table to represent the array?

  - by BeachRunnerJoe

  Hello. I'm using Core Data and I'm trying to figure out the simplest way to store an array of integers in one of my Core Data entities. Currently, my entities contain various arrays of objects that are more complex than a single number, so it makes sense to represent those arrays as tables in my DB and attach them using relationships. If I want to store a simple array of integers, do I need to create a new table with a single column and attach it using a one-to-many relationship? Or is there a more simple way? Thanks in advance for your wisdom!

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• How could I compare these database values in PHP?

  - by Dan

  So a user selects from a drop down list a value. I take this value, put it into a variable, then select from the database the ID value of that table A holding the selected value also. So now I'm trying to use that ID value to get to a many-to-many relationship table that has the selected value from table A to a different table B. The many-to-many relationship table has both IDs. How can I compare this using PHP? So it would be like: $A = $_POST['a']; $sql = "SELECT a, aID from TABLEA WHERE a = $A"; What do I do then to compare the aID with the many-to-many relationships table, then get the other ID in that table and then take that ID to get values from table B?

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• Related Models in Rails 3

  - by Jack

  Hi, I am just starting my first Rails 3 project and am having some difficulties. I have two related models, projects and clients. I have set up the relationships as has_many and belongs_to. However in my projects views I can only access the client_id of the project. I would like to access the client's name and other parameters. I am sure that previously in rails, I could just use project.client.name, but this is not working. Is there a new feature of Rails 3 that I have missed? Cheers

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• Java Util Linked List - how to find next?

  - by drozzy

  When using Java LinkedList how do you find out the element's next or previous relationships? I mean, in a regular linked list I would do something like this: Node node1 = new Node(); Node node2 = new Node(); LinkedList list = new LinkedList(); list.add(node1); list.add(node2); //then my node1 will know who it's next is: assertEquals(node2, node1.next()); But in Java's LinkedList, the data does not seem to be modified. So how do I actually find out who the "next" (or "previous" in the case of doubly-linked lists) element is?

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• how to integrate my users database table with the aspnet_users table that comes with asp.net members

  - by ooo

  i have a database that already has a users table COLUMNS: userID - int loginName - string First - string Last - string i just installed the asp.net membership table. Right now all of my tables are joined into my users table foreign keyed into the "userId" field How do i integrate asp.net_users table into my schema? here are the ideas i thought of: Add a membership_id field to my users table and on new inserts, include that new field in my users table. This seems like the cleanest way as i dont need to break any existing relationships. break all existing relationship and move all of the fields in my user table into the asp.net_users table. This seems like a pain but ultimately will lead to the most simple, normalized solution any thoughts?

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• OOW 2013 Summary for Fusion Middleware Architects & Administrators by Simon Haslam

  - by JuergenKress

  OOW 2013 Summary for Fusion Middleware Architects & Administrators by Simon Haslam This September during Oracle OpenWorld 2013 the weather in San Francisco, as you see can from the photo, was exceptionally sunny. The dramatic final few days of the Americas Cup sailing competition, being held every day in the bay, coincided with the conference and meant that there was almost a holiday feel to the whole event. Here's my annual round-up of what I think was most interesting at OpenWorld 2013 for Fusion Middleware architects and administrators; I hope you find it useful and if you think I've missed something please add a comment! WebLogic and Cloud Application Foundation (CAF) The big WebLogic release of the year has already happened a few months ago with 12.1.2 so I won't duplicate that here. Will Lyons discussed the WebLogic and Coherence roadmap which essentially is that 12.1.3 will probably be released to coincide with SOA 12c next year and that 12.1.4, the next feature-rich WebLogic release, is more likely to be in 2015. This latter release will probably include full Java EE 7 support, have enhancements for multi-tenancy and further auto-scaling features to support increased density (i.e. more WebLogic usage for the same amount of hardware). There's a new Oracle Virtual Assembly Builder (OVAB) out already and an Oracle Traffic Director (OTD) 12c release round the corner too. Also of relevance to administrators is that Oracle has increased the support lifetime for Fusion Middleware 11g (e.g. WebLogic 10.3.6) so that Premier Support will now run to the end of 2018 and Extended Support until 2021 - this should remove any Oracle-driven pressure to upgrade at least. Java Mission Control Java Mission Control (JMC) is the HotSpot Java 7 version of JRockit 6 Mission Control, a very nice performance monitoring tool from Oracle's BEA acquisition. Flight Recorder is a feature built into the JVM which records diagnostic events into, typically, a circular buffer which can then be used for historical analysis, particularly in the case of a JVM crash or hang. It's been available separately for WebLogic only for perhaps a year now but, more significantly, it now includes JVM events and was bundled in with JDK7 Update 40 a few weeks ago. I attended a couple of interesting Java One sessions on JMC/Flight Recorder and have to say it's looking really good - it has all the previous JRMC features except for memory leak detector, plus some enhancements around operative sets and ECID filtering I think. Marcus also showed how you could add your own events into flight recorder by building your own event class - they are then available for graphing alongside all the other events in JMC. This uses a currently an unsupported/undocumented API, but it's also the same one that WebLogic uses for WLDF events so I imagine it is stable. I'm not sure quite whether this would be useful to custom applications, as opposed to infrastructure services or ISV packaged applications, but it was a very nice demonstration. I've been testing JMC / FR enabling on several environments recently and my confidence is growing - it feels robust and I think could very soon be part of my standard builds. Read the full article here. WebLogic Partner Community For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Wiki Technorati Tags: OOW,Simon Haslam,Oracle OpenWorld,WebLogic,WebLogic Community,Oracle,OPN,Jürgen Kress

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• career in Mobile sw/Application Development [closed]

  - by pramod

  i m planning to do a course on Wireless & mobile computing.The syllabus are given below.Please check & let me know whether its worth to do.How is the job prospects after that.I m a fresher & from electronic Engg.The modules are- *Wireless and Mobile Computing (WiMC) – Modules* C, C++ Programming and Data Structures 100 Hours C Revision C, C++ programming tools on linux(Vi editor, gdb etc.) OOP concepts Programming constructs Functions Access Specifiers Classes and Objects Overloading Inheritance Polymorphism Templates Data Structures in C++ Arrays, stacks, Queues, Linked Lists( Singly, Doubly, Circular) Trees, Threaded trees, AVL Trees Graphs, Sorting (bubble, Quick, Heap , Merge) System Development Methodology 18 Hours Software life cycle and various life cycle models Project Management Software: A Process Various Phases in s/w Development Risk Analysis and Management Software Quality Assurance Introduction to Coding Standards Software Project Management Testing Strategies and Tactics Project Management and Introduction to Risk Management Java Programming 110 Hours Data Types, Operators and Language Constructs Classes and Objects, Inner Classes and Inheritance Inheritance Interface and Package Exceptions Threads Java.lang Java.util Java.awt Java.io Java.applet Java.swing XML, XSL, DTD Java n/w programming Introduction to servlet Mobile and Wireless Technologies 30 Hours Basics of Wireless Technologies Cellular Communication: Single cell systems, multi-cell systems, frequency reuse, analog cellular systems, digital cellular systems GSM standard: Mobile Station, BTS, BSC, MSC, SMS sever, call processing and protocols CDMA standard: spread spectrum technologies, 2.5G and 3G Systems: HSCSD, GPRS, W-CDMA/UMTS,3GPP and international roaming, Multimedia services CDMA based cellular mobile communication systems Wireless Personal Area Networks: Bluetooth, IEEE 802.11a/b/g standards Mobile Handset Device Interfacing: Data Cables, IrDA, Bluetooth, Touch- Screen Interfacing Wireless Security, Telemetry Java Wireless Programming and Applications Development(J2ME) 100 Hours J2ME Architecture The CLDC and the KVM Tools and Development Process Classification of CLDC Target Devices CLDC Collections API CLDC Streams Model MIDlets MIDlet Lifecycle MIDP Programming MIDP Event Architecture High-Level Event Handling Low-Level Event Handling The CLDC Streams Model The CLDC Networking Package The MIDP Implementation Introduction to WAP, WML Script and XHTML Introduction to Multimedia Messaging Services (MMS) Symbian Programming 60 Hours Symbian OS basics Symbian OS services Symbian OS organization GUI approaches ROM building Debugging Hardware abstraction Base porting Symbian OS reference design porting File systems Overview of Symbian OS Development – DevKits, CustKits and SDKs CodeWarrior Tool Application & UI Development Client Server Framework ECOM STDLIB in Symbian iPhone Programming 80 Hours Introducing iPhone core specifications Understanding iPhone input and output Designing web pages for the iPhone Capturing iPhone events Introducing the webkit CSS transforms transitions and animations Using iUI for web apps Using Canvas for web apps Building web apps with Dashcode Writing Dashcode programs Debugging iPhone web pages SDK programming for web developers An introduction to object-oriented programming Introducing the iPhone OS Using Xcode and Interface builder Programming with the SDK Toolkit OS Concepts & Linux Programming 60 Hours Operating System Concepts What is an OS? Processes Scheduling & Synchronization Memory management Virtual Memory and Paging Linux Architecture Programming in Linux Linux Shell Programming Writing Device Drivers Configuring and Building GNU Cross-tool chain Configuring and Compiling Linux Virtual File System Porting Linux on Target Hardware WinCE.NET and Database Technology 80 Hours Execution Process in .NET Environment Language Interoperability Assemblies Need of C# Operators Namespaces & Assemblies Arrays Preprocessors Delegates and Events Boxing and Unboxing Regular Expression Collections Multithreading Programming Memory Management Exceptions Handling Win Forms Working with database ASP .NET Server Controls and client-side scripts ASP .NET Web Server Controls Validation Controls Principles of database management Need of RDBMS etc Client/Server Computing RDBMS Technologies Codd’s Rules Data Models Normalization Techniques ER Diagrams Data Flow Diagrams Database recovery & backup SQL Android Application 80 Hours Introduction of android Why develop for android Android SDK features Creating android activities Fundamental android UI design Intents, adapters, dialogs Android Technique for saving data Data base in Androids Maps, Geocoding, Location based services Toast, using alarms, Instant messaging Using blue tooth Using Telephony Introducing sensor manager Managing network and wi-fi connection Advanced androids development Linux kernel security Implement AIDL Interface. Project 120 Hours

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• Countdown of Top 10 Reasons to Never Ever Use a Pie Chart

  - by Tony Wolfram

    Pie charts are evil. They represent much of what is wrong with the poor design of many websites and software applications. They're also innefective, misleading, and innacurate. Using a pie chart as your graph of choice to visually display important statistics and information demonstrates either a lack of knowledge, laziness, or poor design skills. Figure 1: A floating, tilted, 3D pie chart with shadow trying (poorly)to show usage statistics within a graphics application.   Of course, pie charts in and of themselves are not evil. This blog is really about designers making poor decisions for all the wrong reasons. In order for a pie chart to appear on a web page, somebody chose it over the other alternatives, and probably thought they were doing the right thing. They weren't. Using a pie chart is almost always a bad design decision. Figure 2: Pie Chart from an Oracle Reports User Guide   A pie chart does not do the job of effectively displaying information in an elegant visual form.  Being circular, they use up too much space while not allowing their labels to line up. Bar charts, line charts, and tables do a much better job. Expert designers, statisticians, and business analysts have documented their many failings, and strongly urge software and report designers not to use them. It's obvious to them that the pie chart has too many inherent defects to ever be used effectively. Figure 3: Demonstration of how comparing data between multiple pie charts is difficult.   Yet pie charts are still used frequently in today's software applications, financial reports, and websites, often on the opening page as a symbol of how the data inside is represented. In an attempt to get a flashy colorful graphic to break up boring text, designers will often settle for a pie chart that looks like pac man, a colored spinning wheel, or a 3D floating alien space ship.     Figure 4: Best use of a pie chart I've found yet.   Why is the pie chart so popular? Through its constant use and iconic representation as the classic chart, the idea persists that it must be a good choice, since everyone else is still using it. Like a virus or an urban legend, no amount of vaccine or debunking will slow down the use of pie charts, which seem to be resistant to logic and common sense. Even the new iPad from Apple showcases the pie chart as one of its options.     Figure 5: Screen shot of new iPad showcasing pie charts. Regardless of the futility in trying to rid the planet of this often used poor design choice, I now present to you my top 10 reasons why you should never, ever user a pie chart again.    Number 10 - Pie Charts Just Don't Work When Comparing Data Number 9 - You Have A Better Option: The Sorted Horizontal Bar Chart Number 8 - The Pie Chart is Always Round Number 7 - Some Genius Will Make It 3D Number 6 - Legends and Labels are Hard to Align and Read Number 5 - Nobody Has Ever Made a Critical Decision Using a Pie Chart Number 4 - It Doesn't Scale Well to More Than 2 Items Number 3 - A Pie Chart Causes Distortions and Errors Number 2 - Everyone Else Uses Them: Debunking the "Urban Legend" of Pie Charts Number 1 - Pie Charts Make You Look Stupid and Lazy  

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• Migrating VB6 to HTML5 is not a fiction - Customer success story

  - by Webgui

  All of you VB developers in the present or past would probably find it hard to believe that the old VB code can be migrated and modernized into the latest .NET based HTML5 without having to rewrite the application. But we have been working on such tools for the past couple of years and already have several real world applications that were fully 'transposed' from VB6. The solution is called Instant CloudMove and its main tool is called the TranspositionStudio. It is a unique solution that relies on the concept of transposition. Transposition comes from mathematics and music and refers to exchanging elements while everything else remains the same or moving an element as is from one environment to another. This means that we are taking the source code and put it in a modern technological environment with relatively few adjustments.The concept is based on a set of Mapping Expressions which are basically links between an element in the source environment and one in the target environment that has the same functionality. About 95% of the code is usually mapped out-of-the-box and the rest is handled with easy-to-use mapping tools designed for Visual Studio developers providing them with a familiar environment and concepts for completing the mapping and allowing them to extend and customize existing mapping expressions. The solution is also based on a circular workflow that enables developers to make any changes as required until the result is satisfying.As opposed to existing migration solutions that offer automation are usually a “black box” to the user, the transposition concept enables full visibility, flexibility and control over the code and process at all times allowing to also add/change functionalities or upgrade the UI within the process and tools.This is exactly the case with our customer’s aging VB6 PMS (Property Management System) which needed a technological update as well as a design refresh. The decision was to move the VB6 application which had about 1 million lines of code into the latest web technology. Since the application was initially written 13 years ago and had many upgrades since the code must be very patchy and includes unused sections. As a result, the company Mihshuv Group considered rewriting the entire application in Java since it already had the knowledge. Rewrite would allow starting with a clean slate and designing functionality, database architecture, UI without any constraints. On the other hand, rewrite entitles a long and detailed specification work as well as a thorough QA and this translates into a long project with high risk and costs.So the company looked for a migration solution as an alternative; the research lead to Gizmox and after examining the technology it was decided to perform a hybrid project which would include an automatic transposition of the core of the VB6 application (200,000 lines of code) while they redesigning the UI, adding new functionality, deleting unused code and rewriting about 140 reports with Crystal Reports will be done manually using Visual WebGui development tools.The migration part of the project was completed in 65 days by 3 developers from Mihshuv Group guided by Gizmox migration experts while the rewrite and UI upgrade tasks took about the same. So in only a few months period Mihshuv Group generated an up-to-date product, written in the latest Web technology with modern, friendly UI and improved functionality. Guest selection screen of the original VB6 PMS Guest selection screen on the new web–based PMS Compared to the initial plan to rewrite the entire application in Java, the hybrid migration/rewrite approach taken by Mihshuv Group using Gizmox technology proved as a great decision. In terms of time and cost there were substantial savings; from a project that was priced for at least a year (without taking into account the huge risk and uncertainty) it became a few months project only. More about this and other customer stories can be found here

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• How to handle multi-processing of libraries which already spawn sub-processes?

  - by exhuma

  I am having some trouble coming up with a good solution to limit sub-processes in a script which uses a multi-processed library and the script itself is also multi-processed. Both, the library and script are modifiable by us. I believe the question is more about design than actual code, but for what it's worth, it's written in Python. The goal of the library is to hide implementation details of various internet routers. For that reason, the library has a "Proxy" factory method which takes the IP of a router as parameter. The factory then probes the device using a set of possible proxies. Usually, there is one proxy which immediately knows that is is able to send commands to this device. All others usually take some time to return (given a timeout). One thought was already to simply query the device for an identifier, and then select the proper proxy using that, but in order to do so, you would already need to know how to query the device. Abstracting this knowledge is one of the main purposes of the library, so that becomes a little bit of a "circular-requirement"/deadlock: To connect to a device, you need to know what proxy to use, and to know what proxy to create, you need to connect to a device. So probing the device is - as we can see - the best solution so far, apart from keeping a lookup-table somewhere. The library currently kills all remaining processes once a valid proxy has been found. And yes, there is always only one good proxy per device. Currently there are about 12 proxies. So if one create a proxy instance using the factory, 12 sub-processes are spawned. So far, this has been really useful and worked very well. But recently someone else wanted to use this library to "broadcast" a command to all devices. So he took the library, and wrote his own multi-processed script. This obviously spawned 12 * n processes where n is the number of IPs to which he broadcasted. This has given us two problems: The host on which the command was executed slowed down to a near halt. Aborting the script with CTRL+C ground the system to a total halt. Not even the hardware console responded anymore! This may be due to some Python strangeness which still needs to be investigated. Maybe related to http://bugs.python.org/issue8296 The big underlying question, is how to design a library which does multi-processing, so other applications which use this library and want to be multi-processed themselves do not run into system limitations. My first thought was to require a pool to be passed to the library, and execute all tasks in that pool. In that way, the person using the library has control over the usage of system resources. But my gut tells me that there must be a better solution. Disclaimer: My experience with multiprocessing is fairly limited. I have implemented a few straightforward which did not require access control to resources. So I have not yet any practical experience with semaphores or mutexes. p.s.: In the future, we may have enough information to do this without the probing. But the database which would contain the proper information is not yet operational. Also, the design about multiprocessing a multiprocessed library intrigues me :)

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• Application using JOGL stays in Limbo when closing

  - by Roy T.

  I'm writing a game using Java and OpenGL using the JOGL bindings. I noticed that my game doesn't terminate properly when closing the window even though I've set the closing operation of the JFrame to EXIT_ON_CLOSE. I couldn't track down where the problem was so I've made a small reproduction case. Note that on some computers the program terminates normally when closing the window but on other computers (notably my own) something in the JVM keeps lingering, this causes the JFrame to never be disposed and the application to never exit. I haven't found something in common between the computers that had difficulty terminating. All computers had Windows 7, Java 7 and the same version of JOGL and some terminated normally while others had this problem. The test case is as follows: public class App extends JFrame implements GLEventListener { private GLCanvas canvas; @Override public void display(GLAutoDrawable drawable) { GL3 gl = drawable.getGL().getGL3(); gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f); gl.glClear(GL3.GL_COLOR_BUFFER_BIT); gl.glFlush(); } // The overrides for dispose (the OpenGL one), init and reshape are empty public App(String title, boolean full_screen, int width, int height) { //snipped setting the width and height of the JFRAME GLProfile profile = GLProfile.get(GLProfile.GL3); GLCapabilities capabilities = new GLCapabilities(profile); canvas = new GLCanvas(capabilities); canvas.addGLEventListener(this); canvas.setSize(getWidth(), getHeight()); add(canvas); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //!!! setVisible(true); } @Override public void dispose() { System.out.println("HELP"); // } public static void main( String[] args ) { new App("gltut 01", false, 1280, 720); } } As you can see this doesn't do much more than adding a GLCanvas to the frame and registering the main class as the GLEventListener. So what keeps lingering? I'm not sure. I've made some screenshots. The application running normally. The application after the JFrame is closed, note that the JVM still hasn't exited or printed a return code. The application after it was force closed. Note the return code -1, so it wasnt just the JVM standing by or something the application really hadn't exited yet. So what is keeping the application in Limbo? Might it be the circular reference between the GLCanvas and the JFrame? I thought the GC could figure that out. If so how should I deal with that when I want to exit? Is there any other clean-up required when using JOGL? I've tried searching but it doesn't seem to be necessary. Edit, to clarify: there are 2 dispose functions dispose(GLAutoDrawable arg) which is a member of GLEventListener and dispose() which is a member of JFrame. The first one is called correctly (but I wouldn't know what to there, destroying the GLAutoDrawable or the GLCanvas gives an infinite exception loop) the second one is never called.

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• Javascript object dependencies

  - by Anurag

  In complex client side projects, the number of Javascript files can get very large. However, for performance reasons it's good to concatenate these files, and compress the resulting file for sending over the wire. I am having problems in concatenating these as the dependencies are included after they are needed in some cases. For instance, there are 2 files: /modules/Module.js <requires Core.js> /modules/core/Core.js The directories are recursively traversed, and Module.js gets included before Core.js, which causes errors. This is just a simple example where dependencies could span across directories, and there could be other complex cases. There are no circular dependencies though. The Javascript structure I follow is similar to Java packages, where each file defines a single Object (I'm using MooTools, but that's irrelevant). The structure of each javascript file and the dependencies is always consistent: Module.js var Module = new Class({ Implements: Core, ... }); Core.js var Core = new Class({ ... }); What practices do you usually follow to handle dependencies in projects where the number of Javascript files is huge, and there are inter-file dependencies?

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• Repository pattern with lazying loading using POCO

  - by Simon G

  Hi, I'm in the process of starting a new project and creating the business objects and data access etc. I'm just using plain old clr objects rather than any orms. I've created two class libraries: 1) Business Objects - holds all my business objects, all this objects are light weight with only properties and business rules. 2) Repository - this is for all my data access. The majority of my objects will have child list in and my question is what is the best way to lazy load these values as I don't want to bring back unnecessary information if I dont need to. I've thought about when using the "get" on the child property to check if its "null" and if it is call my repository to get the child information. This has two problems from what I can see: 1) The object "knows" how to get itself I would rather no data access logic be held in the object. 2) This required both classes to reference each other which in visual studio throws a circular dependency error. Does anyone have any suggestions on how to overcome this issue or any recommendations on my projects layout and where it can be improved? Thanks

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• OpenCV Python HoughCircles error

  - by Dan

  Hi, I'm working on a program that detects circular shapes in images. I decided a Hough Transform would be the best, and I found one in the OpenCV library. The problem is that when I try to use it I get an error that I have no idea how to fix. Is OpenCV for Python not fully implemented? Is there a fix to the library I need for the program to work? Here's the code: import cv #cv.NamedWindow("camera", 1) capture = cv.CaptureFromCAM(0) while True: img = cv.QueryFrame(capture) gray = cv.CreateImage(cv.GetSize(img), 8, 1) edges = cv.CreateImage(cv.GetSize(img), 8, 1) cv.CvtColor(img, gray, cv.CV_BGR2GRAY) cv.Canny(gray, edges, 50, 200, 3) cv.Smooth(gray, gray, cv.CV_GAUSSIAN, 9, 9) storage = cv.CreateMat(1, 2, cv.CV_32FC3) #This is the line that throws the error cv.HoughCircles(edges, storage, cv.CV_HOUGH_GRADIENT, 2, gray.height/4, 200, 100) #cv.ShowImage("camera", img) if cv.WaitKey(10) == 27: break And here is the error I'm getting: OpenCV Error: Null pinter () in unknown function, file ..\..\..\..\ocv\openc\src\cxcore\cxdatastructs.cpp, line 408 Traceback (most recent call last): File "ellipse-detect-webcam.py", line 20, in cv.HoughCircles(edges, storage, cv.CV_HOUGH_GRADIENT, 2, gray.height/4, 200, 100) cv.error Thanks in advance for the help.

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• Cannot find interface declaration for 'UIResponder'

  - by lfe-eo

  Hi all, I am running into this issue when trying to compile code for an iPhone app that I inherited from a previous developer. I've poked around on a couple forums and it seems like the culprit may be a circular #import somewhere. First - Is there any easy way to find if this is the case/find what files the loop is in? Second - Its definitely possible this isn't the problem. This is the full error (truncated file paths so its easier to view here): In file included from [...]/Frameworks/UIKit.framework/Headers/UIView.h:9, from [...]/Frameworks/UIKit.framework/Headers/UIActivityIndicatorView.h:8, from [...]/Frameworks/UIKit.framework/Headers/UIKit.h:11, from /Users/wbs/Documents/EINetIPhone/EINetIPhone_Prefix.pch:13: [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:15: error: expected ')' before 'UIResponder' [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:17: error: expected '{' before '-' token [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:42: warning: '@end' must appear in an @implementation context [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:51: error: expected ':' before ';' token [...]/Frameworks/UIKit.framework/Headers/UIResponder.h:58: error: cannot find interface declaration for 'UIResponder' As you can see, there are other errors alongside this one. These seem to be simple syntax errors, however, they appear in one of Apple's UIKit files (not my own) so I am seriously doubting that Apple's code is truly producing these errors. I'm stumped as to how to solve this issue. If anyone has any ideas of things I could try or ways/places I could get more info on the problem, I'd really appreciate it. I'm very new to Obj-C and iPhone coding.

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