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• Timezones and the DateTimeField - Django

  - by RadiantHex

  Hi folks, I'm trying to implement a "time ago" feature, for the displaying of items on a site. As I'm caching the pages I wish to use javascript in order to render the "time ago". Javascript knows local time and problably the Timezone of the local machine so I could play with that, but that would require to hard code the server's timezone. Therefore I'm trying to figure out a simple way to pass a ISO 8601 timestamp, in GMT time. Is there any simple and straight forward way for doing this? Help would be much appreciated! =)

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• Learning content for MCSDs: Web Applications and Windows Store Apps using HTML5

  Recently, I started again to learn for various Microsoft certifications. First candidate on my way to MSCD: Web Applications is the Exam 70-480: Programming in HTML5 with JavaScript and CSS3. Motivation to go for a Microsoft exam I guess, this is quite personal but let me briefly describe my intentions to go that exam. First, I'm doing web development since the 1990's. Working with HTML, CSS and Javascript is happening almost daily in my workspace. And honestly, I do not only do 'pure' web development but already integrated several HTML/CSS/Javascript frontend UIs into an existing desktop application (written in Visual FoxPro) inclusive two-way communication and data exchange. Hm, might be an interesting topic for another blog article here... Second, this exam has a very interesting aspect which is listed at the bottom of the exam's details: Credit Toward Certification When you pass Exam 70-480: Programming in HTML5 with JavaScript and CSS3, you complete the requirements for the following certification(s): Programming in HTML5 with JavaScript and CSS3 Specialist Exam 70-480: Programming in HTML5 with JavaScript and CSS3: counts as credit toward the following certification(s): MCSD: Web Applications MCSD: Windows Store Apps using HTML5 So, passing one single exam will earn you specialist certification straight-forward, and opens the path to higher levels of certifications. Preparations and learning path Well, due to a newsletter from Microsoft Learning (MSL) I caught interest in picking up the circumstances and learning materials for this particular exam. As of writing this article there is a promotional / voucher code available which enables you to register for this exam for free! Simply register yourself with or log into your existing account at Prometric, choose the exam for a testing facility near to you and enter the voucher code HTMLJMP (available through 31.03.2013 or while supplies last). Hurry up, there are restrictions... As stated above, I'm already very familiar with web development and the programming flavours involved into this. But of course, it is always good to freshen up your knowledge and reflect on yourself. Microsoft is putting a lot of effort to attract any kind of developers into the 'App Development'. Whether it is for the Windows 8 Store or the Windows Phone 8 Store, doesn't really matter. They simply need more apps. This demand for skilled developers also comes with a nice side-effect: Lots and lots of material to study. During the first couple of hours, I could easily gather high quality preparation material - again for free! Following is just a small list of starting points. If you have more resources, please drop me a message in the comment section, and I'll be glad to update this article accordingly. Developing HTML5 Apps Jump Start This is an accelerated jump start video course on development of HTML5 Apps for Windows 8. There are six modules that are split into two video sessions per module. Very informative and intense course material. This is packed stuff taken from an official preparation course for exam 70-480. Developing Windows Store Apps with HTML5 Jump Start Again, an accelerated preparation video course on Windows 8 Apps. There are six modules with two video sessions each which will catapult you to your exam. This is also related to preps for exam 70-481. Programming Windows 8 Apps with HTML, CSS, and JavaScript Kraig Brockschmidt delves into the ups and downs of Windows 8 App development over 800+ pages. Great eBook to read, study, and to practice the samples - best of all, it's for free. codeSHOW() This is a Windows 8 HTML/JS project with the express goal of demonstrating simple development concepts for the Windows 8 platform. Code, code and more code... absolutely great stuff to study and practice. Microsoft Virtual Academy I already wrote about the MVA in a previous article. Well, if you haven't registered yourself yet, now is the time. The list is not complete for sure, but this might keep you busy for at least one or even two weeks to go through the material. Please don't hesitate to add more resources in the comment section. Right now, I'm already through all videos once, and digging my way through chapter 4 of Kraig's book. Additional material - Pluralsight Apart from those free online resources, I also following some courses from the excellent library of Pluralsight. They already have their own section for Windows 8 development, but of course, you get companion material about HTML5, CSS and Javascript in other sections, too. Introduction to Building Windows 8 Applications Building Windows 8 Applications with JavaScript and HTML Selling Windows 8 Apps HTML5 Fundamentals Using HTML5 and CSS3 HTML5 Advanced Topics CSS3 etc... Interesting to see that Michael Palermo provides his course material on multiple platforms. Fantastic! You might also pay a visit to his personal blog. Hm, it just came to my mind that Aaron Skonnard of Pluralsight publishes so-called '24 hours Learning Paths' based on courses available in the course library. Would be interested to see a combination for Windows 8 App development using HTML5, CSS3 and Javascript in the future. Recommended workspace environment Well, you might have guessed it but this requires Windows 8, Visual Studio 2012 Express or another flavour, and a valid Developers License. Due to an MSDN subscription I working on VS 2012 Premium with some additional tools by Telerik. Honestly, the fastest way to get you up and running for Windows 8 App development is the source code archive of codeSHOW(). It does not only give you all source code in general but contains a couple of SDKs like Bing Maps, Microsoft Advertising, Live ID, and Telerik Windows 8 controls... for free! Hint: Get the Windows Phone 8 SDK as well. Don't worry, while you are studying the material for Windows 8 you will be able to leverage from this knowledge to development for the phone platform, too. It takes roughly one to two hours to get your workspace and learning environment, at least this was my time frame due to slow internet connection and an aged spare machine. ;-) Oh, before I forget to mention it, as soon as you're done, go quickly to the Windows Store and search for ClassBrowserPlus. You might not need it ad hoc for your development using HTML5, CSS and Javascript but I think that it is a great developer's utility that enables you to view the properties, methods and events (along with help text) for all Windows 8 classes. It's always good to look behind the scenes and to explore how it is made. Idea: Start/join a learning group The way you learn new things or intensify your knowledge in a certain technology is completely up to your personal preference. Back in my days at the university, we used to meet once or twice a week in a small quiet room to exchange our progress, questions and problems we ran into. In general, I recommend to any software craftsman to lift your butt and get out to exchange with other developers. Personally, I like this approach, as it gives you new points of view and an insight into others' own experience with certain techniques and how they managed to solve tricky issues. Just keep it relaxed and not too formal after all, and you might a have a good time away from your dull office desk. Give your machine a break, too.

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• ruby / rails / mysql performance degraded on Snow Leopard

  - by adamaig

  I've burned a bunch of hours on this. I'm not having problems getting things to build, but I am seeing that my test suite runs about 2x slower than when I was on OS X 10.5.x . I've spent a lot of time playing around with different optimization settings (learning to avoid homebrew's llvm-gcc compilation). I've just learned that I needed to tweaks /Library/Preferences/SystemConfiguration/com.apple.Boot.plist in order to get the kernel to boot in 64 bit mode. However, my rails app is still running a bit slower than before, even after warming up the mysql server. So what performance tweaks might i need to look into? Right now the stock ruby 1.8.7 runs faster than 1.9.1 for some things, and I'd really like to know if there is anything I should be looking for. All my dev software has been compiled for x86_64, mysql with -O2 optimization, using regular gcc (not llvm-gcc).

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• JPA + Hibernate + Named Query + how to JOIN a subquery result

  - by Srihari

  Can anybody help me in converting the following native query into a Named Query? Native Query: SELECT usr1.user_id, urr1.role_id, usr2.user_id, urr2.role_id, usr1.school_id, term.term_name, count(material.material_id) as "Total Book Count", fpc.FOLLETT_PENDING_COUNT as "Follett Pending Count", rrc.RESOLUTION_REQUIRED_COUNT as "Resolution Required Count" FROM va_school sch JOIN va_user_school_rel usr1 on sch.school_id=usr1.school_id JOIN va_user_role_rel urr1 on usr1.user_id=urr1.user_id and urr1.role_id=1001 JOIN va_user_school_rel usr2 on sch.school_id=usr2.school_id JOIN va_user_role_rel urr2 on usr2.user_id=urr2.user_id and urr2.role_id=1002 JOIN va_term term on term.school_id = usr1.school_id JOIN va_class course on course.term_id = term.term_id JOIN va_material material on material.class_id = course.class_id LEFT JOIN (SELECT VA_CLASS.TERM_ID as "TERM_ID", COUNT(*) as "FOLLETT_PENDING_COUNT" FROM VA_CLASS JOIN VA_MATERIAL ON VA_MATERIAL.CLASS_ID = VA_CLASS.CLASS_ID WHERE VA_CLASS.reference_flag = 'A' AND trunc(VA_MATERIAL.FOLLETT_STATUS) = 0 GROUP BY VA_CLASS.TERM_ID) fpc on term.term_id = fpc.term_id LEFT JOIN (SELECT VA_CLASS.TERM_ID as "TERM_ID", COUNT(*) as "RESOLUTION_REQUIRED_COUNT" FROM VA_CLASS JOIN VA_MATERIAL ON VA_MATERIAL.CLASS_ID = VA_CLASS.CLASS_ID WHERE VA_CLASS.reference_flag = 'A' AND trunc(VA_MATERIAL.FOLLETT_STATUS) = 1 GROUP BY VA_CLASS.TERM_ID) rrc on term.term_id = rrc.term_id WHERE course.reference_flag = 'A' GROUP BY usr1.user_id, urr1.role_id, usr2.user_id, urr2.role_id, usr1.school_id, term.term_name, fpc.FOLLETT_PENDING_COUNT, rrc.RESOLUTION_REQUIRED_COUNT ORDER BY usr1.school_id, term.term_name; Thanks in advance. Srihari

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• phantom error "error parsing XML: unbound prefix"

  - by Brad Hein

  The error "error parsing XML: unbound prefix" shows up on my main layout: main.xml when I first open Eclipse. To make the error go away, all I have to do is make a modification to the file, then undo it, then hit save (have to make a change in order to be able to save file and thus trigger the new syntax check). My environment is: Fedora Eclipse Platform Version: 3.4.2 Based on build id: 20090211-1700 My target is Android API level 5. The first time I saw the error I spent a long time trying to track down "the problem" but later realized there isn't really a problem, it's just a phantom error. Screenshot: http://i50.tinypic.com/2i89iee.jpg Who should I report this to?

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• Best Data Structure For Time Series Data

  - by TriParkinson

  Hi all, I wonder if someone could take a minute out of their day to give their two cents on my problem. I would like some suggestions on what would be the best data structure for representing, on disk, a large data set of time series data. The main priority is speed of insertion, with other priorities in decreasing order; speed of retrieval, size on disk, size in memory, speed of removal. I have seen that B+ trees are often used in database because of their fast search times, but how about for fast insertion times? Is a linked list really the way to go? Thanks in advance for your time, Tri

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• Using Dynamics AX's Business Conectors to Generate Sales Orders

  - by FelipeFiali

  So, just like the title says, I need to create an application that gets data from another Database, and shoves it through Dynamics AX's throat. This data comes from a portal, not Enterprise Portal, but a PHP one. It stores some data from the order in a separate database. So as said, I need to 'import' that to AX, creating the sales orders with the data I have from the other database. Also I'd like some references on Business Conector too, does it handle all those RECIDS and references that AX uses for me? Thanks in advance. EDIT: OK, I'm able to insert records in AX's database, theres just one problem. I can't generate the internal ID. Like, the 'AccountNum' field for the CustTable. Is there a way to capture it from business connector?

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• Diff tool to align shuffled lines

  - by Ken Bloom

  Suppose I have two documents that are identical except the lines are shuffled. Is there a tool that can show me which lines in document A correspond to which lines on document B by drawing lines to connect them (kinda like Cairo does for machine translation word alignments)? What if the files have some level of differing lines (I don't want to figure out which lines are similar to each other -- if there isn't an exact match for a line, then that line has no match.) Note: I am not looking to sort the files and compare them, rather I am looking to get a visualization of how far out of order the files are relative to each other, and which particular regions tend to move together, and which tend to be shuffled.

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• How to implement UIViewController rotation in response to orientation changes?

  - by Greg Maletic

  My app has about 10 different UIViewControllers, just one of which I want to switch to landscape mode if the device is rotated. (All the rest, I want to keep in portrait.) In order to implement rotation on that one view, I needed to implement its controller's 'shouldAutorotate' method and return YES. Since this view is accessed via a navigation controller, I also needed to create a subclass of UINavigationController that implements 'shouldAutorotate' and return YES. This solution works, but too well. I find that all of the UIViewControllers I push onto my subclass of UINavigationController respond to rotation, even if I implement 'shouldAutorotate' and return NO. (Remember: I only want one particular UIViewController to respond to rotation, not every one in the navigation controller's stack.) So, my question is: how do I best do this? All the solutions I can come up with seem 1) cumbersome, and 2) worse, don't seem to work. Thanks very much.

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• checkins/recent not returning comments or even counts of comments

  - by Gilbert

  My application has been using the checkins/recent endpoint to show where all the current users friends are currently at and I had included a button the user could press to comment on a checkin. The button used to have the comment count on it until recently. It seems the checkins/recent endpoint no longer returns comments or even a comment count for those checkins. I would have to query each checkin in order to get the comment count which adds to the data usage not to mention API usage counts. Is there another way to do this that I'm not seeing? Could you please at least put the comment count back? You have the photo information, why not comments? Thanks

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• Querying a Cassandra column family for rows that have not been updated in X days

  - by knorv

  I'm moving an existing MySQL based application over to Cassandra. So far finding the equivalent Cassandra data model has been quite easy, but I've stumbled on the following problem for which I'd appreciate some input: Consider a MySQL table holding millions of entities: CREATE TABLE entities ( id INT AUTO_INCREMENT NOT NULL, entity_information VARCHAR(...), entity_last_updated DATETIME, PRIMARY KEY (id), KEY (entity_last_updated) ); The table is regularly queried for entities that need to be updated: SELECT id FROM entities WHERE entity_last_updated IS NULL OR entity_last_updated < DATE_ADD(NOW(), INTERVAL -7*24 HOUR) ORDER BY entity_last_updated ASC; The entities returned by this queries are then updated using the following query: UPDATE entities SET entity_information = ?, entity_last_updated = NOW() WHERE id = ?; What would be the corresponding Cassandra data model that would allow me to store the given information and effectively query the entities table for entities that need to be updated (that is: entities that have not been updated in the last seven days)?

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• Can operator= may be not a member?

  - by atch

  Having construction in a form: struct Node { Node():left_(nullptr), right_(nullptr) { } int id_; Node* left_; Node* right_; }; I would like to enable syntax: Node parent; Node child; parent.right_ = child; So in order to do so I need: Node& operator=(Node* left, Node right); but I'm getting msg that operator= has to be a member fnc; Is there any way to circumvent this restriction?

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• Problem building with MSBuild on Team Build

  - by mrwayne

  Hi, I have recently upgraded from TFS2005 to TFS2010 (and sub-sequently the team build server). I used to be able to get a team build on one of my solutions to work pretty easily, (see structure below) Solution |_Web Site | |_Bin | |_Other Files |_Project 1 |_Project 2 |_Project (n) Now, i can no longer get a build working correctly as it doesnt appear to build all my projects any longer (i've had to create a new build definition). Either that, or its not building the projects in such an order that when it hits project X, that a project it depends on (Project A), has not yet been built, and as such fails. I'm just basically trying to build a web site (not web application project), with some Dependant / linked projects. Why must it be so hard! Everything builds fine in the IDE. If i even open the solution copied to the build server under the 'Sources' directory, i am able to build it fine in the IDE on that server. No such luck with MSBuild though. Thoughts?

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• group expression in jasper reports

  - by ed1t

  I've a report which has a has 5 columns on each page and I have a group defined which shows columns related to A | B | C | D | E - main column X | Y | Z - group - A is the key I have my query ORDER BY A, but when it is displayed it doesn't print the results in next page if A is changed. Following is how I have a group defined. <group name="A" isResetPageNumber="true" > <groupExpression><![CDATA[$F{A}]]></groupExpression> <groupHeader> <band/> </groupHeader> <groupFooter> <band/> </groupFooter> </group> does A need to be part of the group?

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• Debugging problems in Visual Studio 2005 - No source code available for the current location

  - by espais

  Hi all I've searched up and down Google for others with a similar problem, and while I can find the error I don't think that other people have the same base problem that I do. Basically, I had to create a project for a unit-testing environment in order to run this test suite. First, I add my original C file, compile, and then a test file (C++) is generated. I then exclude my original source from the project, include this test script (which includes the original source at the top), and then run. I can debug the test file fine, but when it jumps to the original C file I get the dreaded 'no source code available for the current location' error. Both files are located within the same location, and I compiled the original file without any issue. Anybody have any thoughts about this? Its driving me crazy!

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• Problems with mod_Rewrite

  - by Giorgi

  Hello, Originally I had following .htaccess file: php_value display_errors 1 php_value error_reporting 7 AddDefaultCharset utf-8 Options -Indexes <Files ~ ".*\.(info|tpl)$"> Order allow,deny Deny from all </Files> RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.*)$ /index.php/$1 [L,QSA] Which triggered 500 internal server error, so I moved first two lines to the php.ini file. after that, error disappeared, but redirect is not working, it simply redirects to the empty page, error log shows: file not found also, another log shows: PHP Warning: Unknown: open_basedir restriction in effect. File() is not within the allowed path(s): (/home/:/usr/lib/php:/usr/local/lib/php:/tmp/:/usr/local/:/usr/bin) in Unknown on line 0 I tried to write in RewriteLog which triggered 500 server error again A little help? Thank you in advance P.S. cPanel 11.24.5-STABLE (Build: 38506) Apache version 2.2.15 (Unix) MySQL version 5.0.85-community PHP version 5.2.9 Operating system Linux Apache/2.2.15 (Unix) mod_ssl/2.2.15 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 mod_fcgid/2.3.5

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• Upgrading Visual Studio 2010 RC to RTM

  - by Brant Bobby

  I have the RC build of VS2010 installed on my computer. Now that the RTM build is out, I want to upgrade. Aside from the main Visual Studio package and .NET Framework 4, what else should I remove before I install the RTM build in order to minimize potential breakage/conflicts? VS2010 installs a whole bunch of ancillary packages and I'm not sure which ones have been upgraded between RC and RTM. (Extra credit: I've got another machine that is still running Beta 2. Would the procedure be the same?)

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• Best Allocation Algorithm

  - by shaju

  Hi, I am looking for a best allocation algorithm for the below scenario. We have requirement for say 18 pieces. I have the stock in my shelf as follows. Bin A - 10 Bin B - 6 Bin C - 3 Bin D - 4 Algorithm should propose the bins in the following order Bin A(10) , Bin D (4), Bin C (3) Real scenario we have n number of bins with different quantities.We need to find the optimal combination. Objective is to maxmize the allocation quantity. Can you please help. Regards, Shaju

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• Why can't I declare C# methods virtual and static?

  - by Luke

  I have a helper class that is just a bunch of static methods and would like to subclass the helper class. Some behavior is unique depending on the subclass so I would like to call a virtual method from the base class, but since all the methods are static I can't create a plain virtual method (need object reference in order to access virtual method). Is there any way around this? I guess I could use a singleton.. HelperClass.Instance.HelperMethod() isn't so much worse than HelperClass.HelperMethod(). Brownie points for anyone that can point out some languages that support virtual static methods. Edit: OK yeah I'm crazy. Google search results had me thinking I wasn't for a bit there.

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• Compound IDENTITY column in SQL SERVER 2008

  - by Asaf R

  An Orders table has a CustomerId column and an OrderId column. For certain reasons it's important that OrderId is no longer than 2-bytes. There will be several million orders in total, which makes 2-bytes not enough. A customer will have no more than several thousand orders making 2-bytes enough. The obvious solution is to have the (CustomerId, OrderId) be unique rather than (OrderId) itself. The problem is generating the next Customer's OrderId. Preferably, without creating a separate table for each customer (even if it contains only an IDENTITY column), in order to keep the upper layers of the solution simple. Q: how would you generate the next OrderId so that (CustomerId, OrderId) is unique but OrderId itself is allowed to have repetitions? Does Sql Server 2008 have a built in functionality for doing this? For lack of a better term I'm calling it a Compound IDENTITY column.

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• Can NSDictionary be used with TableView on iPhone?

  - by bobo

  In a UITableViewController subclass, there are some methods that need to be implemented in order to load the data and handle the row selection event: - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; //there is only one section needed for my table view } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [myList count]; //myList is a NSDictionary already populated in viewDidLoad method } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease ]; } // indexPath.row returns an integer index, // but myList uses keys that are not integer, // I don't know how I can retrieve the value and assign it to the cell.textLabel.text return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // Handle row on select event, // but indexPath.row only returns the index, // not a key of the myList NSDictionary, // this prevents me from knowing which row is selected } How is NSDictionary supposed to work with TableView? What is the simplest way to get this done?

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• Subsonic 3.0 Query limit with MySQL c#.net LinQ

  - by omegawkd

  Hello, a quick question which may or may not be easily answered. Currently, in order to return a limited result set of data to my calling reference using SubSonic I use a similar function as below: _DataSet = from CatSet in t2_aspnet_shopping_item_category.All() join CatProdAssignedLink in t2_aspnet_shopping_link_categoryproduct.All() on CatSet.CategoryID equals CatProdAssignedLink.CategoryID join ProdSet in t2_aspnet_shopping_item_product.All() on CatProdAssignedLink.ProductID equals ProdSet.ProductID where ProdSet.ProductID == __ProductID orderby CatProdAssignedLink.LinkID ascending select CatSet; and select the first item from the data set. Is there a way to limit the lookup initially to a certain amount of rows? I'm using MySQL as the base database.

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• Tomcat JAXB 1 and 2 linkage error

  - by Alex

  I'm running a tomcat 6, spring, apache cxf webservice, know it is a must to add one third party library to my webapp to fulfill an order. I have jaxb-impl-2.1.12.jar for apache cxf in WEB-INF/lib folder and the new library which contains the JAXB 1.0 runtime. JAXB 2 ist used by apache cxf for dynamic clients (i need them). So is there a possibility to run the webapps with both libraries? Error: Caused by: java.lang.LinkageError: You are trying to run JAXB 2.0 runtime but you have old JAXB 1.0 runtime earlier in the classpath. Please remove the JAXB 1.0 runtime for 2.0 runtime to work correctly.

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• MySQL Cluster 7.3 Labs Release – Foreign Keys Are In!

  - by Mat Keep

  0 0 1 1097 6254 Homework 52 14 7337 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:EN-US;} Summary (aka TL/DR): Support for Foreign Key constraints has been one of the most requested feature enhancements for MySQL Cluster. We are therefore extremely excited to announce that Foreign Keys are part of the first Labs Release of MySQL Cluster 7.3 – available for download, evaluation and feedback now! (Select the mysql-cluster-7.3-labs-June-2012 build) In this blog, I will attempt to discuss the design rationale, implementation, configuration and steps to get started in evaluating the first MySQL Cluster 7.3 Labs Release. Pace of Innovation It was only a couple of months ago that we announced the General Availability (GA) of MySQL Cluster 7.2, delivering 1 billion Queries per Minute, with 70x higher cross-shard JOIN performance, Memcached NoSQL key-value API and cross-data center replication.  This release has been a huge hit, with downloads and deployments quickly reaching record levels. The announcement of the first MySQL Cluster 7.3 Early Access lab release at today's MySQL Innovation Day event demonstrates the continued pace in Cluster development, and provides an opportunity for the community to evaluate and feedback on new features they want to see. What’s the Plan for MySQL Cluster 7.3? Well, Foreign Keys, as you may have gathered by now (!), and this is the focus of this first Labs Release. As with MySQL Cluster 7.2, we plan to publish a series of preview releases for 7.3 that will incrementally add new candidate features for a final GA release (subject to usual safe harbor statement below*), including: - New NoSQL APIs; - Features to automate the configuration and provisioning of multi-node clusters, on premise or in the cloud; - Performance and scalability enhancements; - Taking advantage of features in the latest MySQL 5.x Server GA. Design Rationale MySQL Cluster is designed as a “Not-Only-SQL” database. It combines attributes that enable users to blend the best of both relational and NoSQL technologies into solutions that deliver web scalability with 99.999% availability and real-time performance, including: Concurrent NoSQL and SQL access to the database; Auto-sharding with simple scale-out across commodity hardware; Multi-master replication with failover and recovery both within and across data centers; Shared-nothing architecture with no single point of failure; Online scaling and schema changes; ACID compliance and support for complex queries, across shards. Native support for Foreign Key constraints enables users to extend the benefits of MySQL Cluster into a broader range of use-cases, including: - Packaged applications in areas such as eCommerce and Web Content Management that prescribe databases with Foreign Key support. - In-house developments benefiting from Foreign Key constraints to simplify data models and eliminate the additional application logic needed to maintain data consistency and integrity between tables. Implementation The Foreign Key functionality is implemented directly within MySQL Cluster’s data nodes, allowing any client API accessing the cluster to benefit from them – whether using SQL or one of the NoSQL interfaces (Memcached, C++, Java, JPA or HTTP/REST.) The core referential actions defined in the SQL:2003 standard are implemented: CASCADE RESTRICT NO ACTION SET NULL In addition, the MySQL Cluster implementation supports the online adding and dropping of Foreign Keys, ensuring the Cluster continues to serve both read and write requests during the operation. An important difference to note with the Foreign Key implementation in InnoDB is that MySQL Cluster does not support the updating of Primary Keys from within the Data Nodes themselves - instead the UPDATE is emulated with a DELETE followed by an INSERT operation. Therefore an UPDATE operation will return an error if the parent reference is using a Primary Key, unless using CASCADE action, in which case the delete operation will result in the corresponding rows in the child table being deleted. The Engineering team plans to change this behavior in a subsequent preview release. Also note that when using InnoDB "NO ACTION" is identical to "RESTRICT". In the case of MySQL Cluster “NO ACTION” means “deferred check”, i.e. the constraint is checked before commit, allowing user-defined triggers to automatically make changes in order to satisfy the Foreign Key constraints. Configuration There is nothing special you have to do here – Foreign Key constraint checking is enabled by default. If you intend to migrate existing tables from another database or storage engine, for example from InnoDB, there are a couple of best practices to observe: 1. Analyze the structure of the Foreign Key graph and run the ALTER TABLE ENGINE=NDB in the correct sequence to ensure constraints are enforced 2. Alternatively drop the Foreign Key constraints prior to the import process and then recreate when complete. Getting Started Read this blog for a demonstration of using Foreign Keys with MySQL Cluster.  You can download MySQL Cluster 7.3 Labs Release with Foreign Keys today - (select the mysql-cluster-7.3-labs-June-2012 build) If you are new to MySQL Cluster, the Getting Started guide will walk you through installing an evaluation cluster on a singe host (these guides reflect MySQL Cluster 7.2, but apply equally well to 7.3) Post any questions to the MySQL Cluster forum where our Engineering team will attempt to assist you. Post any bugs you find to the MySQL bug tracking system (select MySQL Cluster from the Category drop-down menu) And if you have any feedback, please post them to the Comments section of this blog. Summary MySQL Cluster 7.2 is the GA, production-ready release of MySQL Cluster. This first Labs Release of MySQL Cluster 7.3 gives you the opportunity to preview and evaluate future developments in the MySQL Cluster database, and we are very excited to be able to share that with you. Let us know how you get along with MySQL Cluster 7.3, and other features that you want to see in future releases. * Safe Harbor Statement This information is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

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• Is it possible to create a quine in every turing-complete language?

  - by sub

  I just wanted to know if it is 100% possible, if my language is turing-complete, to write a program in it that prints itself out (of course not using a file reading function) So if the language just has the really necessary things in order to make it turing complete (I would prove that by translating Brainf*ck code to it), like output, variables, conditions and gotos (hell yes, gotos), can I try writing a quine in it? I'm also asking this because I'm not sure that a quine directly fits into Turing's law that the turing machine is capable of any computational task. I just want to know so I don't try for years without knowing that it may be impossible.

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