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  • Implementation of "Automatic Lightweight Migration" for Core Data (iPhone)

    - by RickiG
    Hi I would like to make my app able to do an automatic lightweight migration when I add new attributes to my core data model. In the guide from Apple this is the only info on the subject I could find: Automatic Lightweight Migration To request automatic lightweight migration, you set appropriate flags in the options dictionary you pass in addPersistentStoreWithType:configuration:URL:options:error:. You need to set values corresponding to both the NSMigratePersistentStoresAutomaticallyOption and the NSInferMappingModelAutomaticallyOption keys to YES: NSError *error; NSURL *storeURL = <#The URL of a persistent store#>; NSPersistentStoreCoordinator *psc = <#The coordinator#>; NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys: [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil]; if (![psc addPersistentStoreWithType:<#Store type#> configuration:<#Configuration or nil#> URL:storeURL options:options error:&error]) { // Handle the error. } My NSPersistentStoreCoordinator is initialized in this way: - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { if (persistentStoreCoordinator != nil) { return persistentStoreCoordinator; } NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"FC.sqlite"]]; NSError *error = nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } return persistentStoreCoordinator; } I am having trouble seeing where and how I should add the Apple code to get the Automatic Lightweight Migration working?

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  • Migrating a Large amount of data from old publishing site to new site

    - by tommizzle
    Hi, I am currently in the process of creating a new news/publishing site on the Movable Type platform. There are around 20 or so sites with 20,000+ rows of data to be moved/aggregated to ~8 sites (we have a number of location specific sites and are going to aggregate the content from these into 1 single site for each niche). We have discussed how to do this and came to the conclusion that it would probably be better to hire somebody to do it (I could probably do it, but i'm limited on time and am sure that a specialist would be more efficient). So my questions to you guys are: 1) What kind of skill set should we look for in an applicant? 2) There will be a large amount of input from our side... is getting somebody to work remotely out of the question? 3) How long would a task like this traditionally take (I know this question is very subjective, but an estimation would be awesome)? 4) Do you have any recommendations for firms who would be able to take on a large task like this? Thanks in advance, Tom

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  • Spring Data Neo4J @Indexed(unique = true) not working

    - by Markus Lamm
    I'm new to Neo4J and I have, probably an easy question. There're NodeEntitys in my application, a property (name) is annotated with @Indexed(unique = true) to achieve the uniqueness like I do in JPA with @Column(unique = true). My problem is, that when I persist an entity with a name that already exists in my graph, it works fine anyway. But I expected some kind of exception here...?! Here' s an overview over basic my code: @NodeEntity public abstract class BaseEntity implements Identifiable { @GraphId private Long entityId; ... } public class Role extends BaseEntity { @Indexed(unique = true) private String name; ... } public interface RoleRepository extends GraphRepository<Role> { Role findByName(String name); } @Service public class RoleServiceImpl extends BaseEntityServiceImpl<Role> implements { private RoleRepository repository; @Override @Transactional public T save(final T entity) { return getRepository().save(entity); } } And this is my test: @Test public void testNameUniqueIndex() { final List<Role> roles = Lists.newLinkedList(service.findAll()); final String existingName = roles.get(0).getName(); Role newRole = new Role.Builder(existingName).build(); newRole = service.save(newRole); } That's the point where I expect something to go wrong! How can I ensure the uniqueness of a property, without checking it for myself?? THANKS IN ADVANCE FOR ANY IDEAS!! P.S.: I'm using neo4j 1.8.M07, spring-data-neo4j 2.1.0.BUILD-SNAPSHOT and Spring 3.1.2.RELEASE.

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  • nested sortable table rows jquery

    - by FLY
    Hi, I am trying to sort rows of a table, and put them as 'child' elements of a table row I found this: http://code.google.com/p/nestedsortables/ this works with ul li lists, but i want to build it for a table. <table> <thead> <th>tablehead</th> </thead> <tbody> <tr><td>somevalue</td></tr> <tr><td>somevalue2</td></tr> </tbody> </table> so yeah you can use jquery.sortable() and sort the rows, but i want 'somevalue' to be become a child element of 'somevalue2' if you drag 'somevalue' over 'somevalue2' I don't know if it is posible with a table. can anyone help me? Thnx!

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  • Assert parameters in a table-valued UDF

    - by Clay Lenhart
    Is there a way to create "asserts" on the parameters of a table-valued UDF. I'd like to use a table-valued UDF for performance reasons, however I know that certain parameter combinations (like start and end dates that are more than a month apart) will cause performance issues on the server for all users. End users query the database via Excel using UDFs. UDFs (and table-valued UDFs in particular) are useful when the data is too large for Excel. Users write simple SQL queries that categorizes the data into groups to reduce the number of rows. For example, the user may be interested in weekly aggregates rather than hourly ones. Users write a group by SELECT statement to reduce the rows by 24x7=168 times. I know I can write RAISERROR statements in multistatement UDFs, but table-valued UDFs are integrated in the query optimizer so these queries are more efficient with table-valued UDFs. So, can I define assertions on the parameters passed to a table-valued UDF?

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  • Sensitive Data Storage - Best Practices

    - by Kenneth
    I recently started working on a personal project where I was connecting to a database using Java. This got me thinking. I have to provide the login information for a database account on the DB server in order to access the database. But if I hard code it in then it would be possible for someone to decompile the program and extract that login info. If I store it in an external setup file then the same problem exists only it would be even easier for them to get it. I could encrypt the data before storing it in either place but it seems like that's not really a fail safe either and I'm no encryption expert by any means. So what are some best practices for storing sensitive setup data for a program?

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  • Table sorting & pagination with jQuery and Razor in ASP.NET MVC

    - by hajan
    Introduction jQuery enjoys living inside pages which are built on top of ASP.NET MVC Framework. The ASP.NET MVC is a place where things are organized very well and it is quite hard to make them dirty, especially because the pattern enforces you on purity (you can still make it dirty if you want so ;) ). We all know how easy is to build a HTML table with a header row, footer row and table rows showing some data. With ASP.NET MVC we can do this pretty easy, but, the result will be pure HTML table which only shows data, but does not includes sorting, pagination or some other advanced features that we were used to have in the ASP.NET WebForms GridView. Ok, there is the WebGrid MVC Helper, but what if we want to make something from pure table in our own clean style? In one of my recent projects, I’ve been using the jQuery tablesorter and tablesorter.pager plugins that go along. You don’t need to know jQuery to make this work… You need to know little CSS to create nice design for your table, but of course you can use mine from the demo… So, what you will see in this blog is how to attach this plugin to your pure html table and a div for pagination and make your table with advanced sorting and pagination features.   Demo Project Resources The resources I’m using for this demo project are shown in the following solution explorer window print screen: Content/images – folder that contains all the up/down arrow images, pagination buttons etc. You can freely replace them with your own, but keep the names the same if you don’t want to change anything in the CSS we will built later. Content/Site.css – The main css theme, where we will add the theme for our table too Controllers/HomeController.cs – The controller I’m using for this project Models/Person.cs – For this demo, I’m using Person.cs class Scripts – jquery-1.4.4.min.js, jquery.tablesorter.js, jquery.tablesorter.pager.js – required script to make the magic happens Views/Home/Index.cshtml – Index view (razor view engine) the other items are not important for the demo. ASP.NET MVC 1. Model In this demo I use only one Person class which defines Person entity with several properties. You can use your own model, maybe one which will access data from database or any other resource. Person.cs public class Person {     public string Name { get; set; }     public string Surname { get; set; }     public string Email { get; set; }     public int? Phone { get; set; }     public DateTime? DateAdded { get; set; }     public int? Age { get; set; }     public Person(string name, string surname, string email,         int? phone, DateTime? dateadded, int? age)     {         Name = name;         Surname = surname;         Email = email;         Phone = phone;         DateAdded = dateadded;         Age = age;     } } 2. View In our example, we have only one Index.chtml page where Razor View engine is used. Razor view engine is my favorite for ASP.NET MVC because it’s very intuitive, fluid and keeps your code clean. 3. Controller Since this is simple example with one page, we use one HomeController.cs where we have two methods, one of ActionResult type (Index) and another GetPeople() used to create and return list of people. HomeController.cs public class HomeController : Controller {     //     // GET: /Home/     public ActionResult Index()     {         ViewBag.People = GetPeople();         return View();     }     public List<Person> GetPeople()     {         List<Person> listPeople = new List<Person>();                  listPeople.Add(new Person("Hajan", "Selmani", "[email protected]", 070070070,DateTime.Now, 25));                     listPeople.Add(new Person("Straight", "Dean", "[email protected]", 123456789, DateTime.Now.AddDays(-5), 35));         listPeople.Add(new Person("Karsen", "Livia", "[email protected]", 46874651, DateTime.Now.AddDays(-2), 31));         listPeople.Add(new Person("Ringer", "Anne", "[email protected]", null, DateTime.Now, null));         listPeople.Add(new Person("O'Leary", "Michael", "[email protected]", 32424344, DateTime.Now, 44));         listPeople.Add(new Person("Gringlesby", "Anne", "[email protected]", null, DateTime.Now.AddDays(-9), 18));         listPeople.Add(new Person("Locksley", "Stearns", "[email protected]", 2135345, DateTime.Now, null));         listPeople.Add(new Person("DeFrance", "Michel", "[email protected]", 235325352, DateTime.Now.AddDays(-18), null));         listPeople.Add(new Person("White", "Johnson", null, null, DateTime.Now.AddDays(-22), 55));         listPeople.Add(new Person("Panteley", "Sylvia", null, 23233223, DateTime.Now.AddDays(-1), 32));         listPeople.Add(new Person("Blotchet-Halls", "Reginald", null, 323243423, DateTime.Now, 26));         listPeople.Add(new Person("Merr", "South", "[email protected]", 3232442, DateTime.Now.AddDays(-5), 85));         listPeople.Add(new Person("MacFeather", "Stearns", "[email protected]", null, DateTime.Now, null));         return listPeople;     } }   TABLE CSS/HTML DESIGN Now, lets start with the implementation. First of all, lets create the table structure and the main CSS. 1. HTML Structure @{     Layout = null;     } <!DOCTYPE html> <html> <head>     <title>ASP.NET & jQuery</title>     <!-- referencing styles, scripts and writing custom js scripts will go here --> </head> <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th> value </th>                 </tr>             </thead>             <tbody>                 <tr>                     <td>value</td>                 </tr>             </tbody>             <tfoot>                 <tr>                     <th> value </th>                 </tr>             </tfoot>         </table>         <div id="pager">                      </div>     </div> </body> </html> So, this is the main structure you need to create for each of your tables where you want to apply the functionality we will create. Of course the scripts are referenced once ;). As you see, our table has class tablesorter and also we have a div with id pager. In the next steps we will use both these to create the needed functionalities. The complete Index.cshtml coded to get the data from controller and display in the page is: <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </thead>             <tbody>                 @{                     foreach (var p in ViewBag.People)                     {                                 <tr>                         <td>@p.Name</td>                         <td>@p.Surname</td>                         <td>@p.Email</td>                         <td>@p.Phone</td>                         <td>@p.DateAdded</td>                     </tr>                     }                 }             </tbody>             <tfoot>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </tfoot>         </table>         <div id="pager" style="position: none;">             <form>             <img src="@Url.Content("~/Content/images/first.png")" class="first" />             <img src="@Url.Content("~/Content/images/prev.png")" class="prev" />             <input type="text" class="pagedisplay" />             <img src="@Url.Content("~/Content/images/next.png")" class="next" />             <img src="@Url.Content("~/Content/images/last.png")" class="last" />             <select class="pagesize">                 <option selected="selected" value="5">5</option>                 <option value="10">10</option>                 <option value="20">20</option>                 <option value="30">30</option>                 <option value="40">40</option>             </select>             </form>         </div>     </div> </body> So, mainly the structure is the same. I have added @Razor code to create table with data retrieved from the ViewBag.People which has been filled with data in the home controller. 2. CSS Design The CSS code I’ve created is: /* DEMO TABLE */ body {     font-size: 75%;     font-family: Verdana, Tahoma, Arial, "Helvetica Neue", Helvetica, Sans-Serif;     color: #232323;     background-color: #fff; } table { border-spacing:0; border:1px solid gray;} table.tablesorter thead tr .header {     background-image: url(images/bg.png);     background-repeat: no-repeat;     background-position: center right;     cursor: pointer; } table.tablesorter tbody td {     color: #3D3D3D;     padding: 4px;     background-color: #FFF;     vertical-align: top; } table.tablesorter tbody tr.odd td {     background-color:#F0F0F6; } table.tablesorter thead tr .headerSortUp {     background-image: url(images/asc.png); } table.tablesorter thead tr .headerSortDown {     background-image: url(images/desc.png); } table th { width:150px;            border:1px outset gray;            background-color:#3C78B5;            color:White;            cursor:pointer; } table thead th:hover { background-color:Yellow; color:Black;} table td { width:150px; border:1px solid gray;} PAGINATION AND SORTING Now, when everything is ready and we have the data, lets make pagination and sorting functionalities 1. jQuery Scripts referencing <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.pager.js")" type="text/javascript"></script> 2. jQuery Sorting and Pagination script   <script type="text/javascript">     $(function () {         $("table.tablesorter").tablesorter({ widthFixed: true, sortList: [[0, 0]] })         .tablesorterPager({ container: $("#pager"), size: $(".pagesize option:selected").val() });     }); </script> So, with only two lines of code, I’m using both tablesorter and tablesorterPager plugins, giving some options to both these. Options added: tablesorter - widthFixed: true – gives fixed width of the columns tablesorter - sortList[[0,0]] – An array of instructions for per-column sorting and direction in the format: [[columnIndex, sortDirection], ... ] where columnIndex is a zero-based index for your columns left-to-right and sortDirection is 0 for Ascending and 1 for Descending. A valid argument that sorts ascending first by column 1 and then column 2 looks like: [[0,0],[1,0]] (source: http://tablesorter.com/docs/) tablesorterPager – container: $(“#pager”) – tells the pager container, the div with id pager in our case. tablesorterPager – size: the default size of each page, where I get the default value selected, so if you put selected to any other of the options in your select list, you will have this number of rows as default per page for the table too. END RESULTS 1. Table once the page is loaded (default results per page is 5 and is automatically sorted by 1st column as sortList is specified) 2. Sorted by Phone Descending 3. Changed pagination to 10 items per page 4. Sorted by Phone and Name (use SHIFT to sort on multiple columns) 5. Sorted by Date Added 6. Page 3, 5 items per page   ADDITIONAL ENHANCEMENTS We can do additional enhancements to the table. We can make search for each column. I will cover this in one of my next blogs. Stay tuned. DEMO PROJECT You can download demo project source code from HERE.CONCLUSION Once you finish with the demo, run your page and open the source code. You will be amazed of the purity of your code.Working with pagination in client side can be very useful. One of the benefits is performance, but if you have thousands of rows in your tables, you will get opposite result when talking about performance. Hence, sometimes it is nice idea to make pagination on back-end. So, the compromise between both approaches would be best to combine both of them. I use at most up to 500 rows on client-side and once the user reach the last page, we can trigger ajax postback which can get the next 500 rows using server-side pagination of the same data. I would like to recommend the following blog post http://weblogs.asp.net/gunnarpeipman/archive/2010/09/14/returning-paged-results-from-repositories-using-pagedresult-lt-t-gt.aspx, which will help you understand how to return page results from repository. I hope this was helpful post for you. Wait for my next posts ;). Please do let me know your feedback. Best Regards, Hajan

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  • The Best Ways to Lock Down Your Multi-User Computer

    - by Lori Kaufman
    Whether you’re sharing a computer with other family members or friends at home, or securing computers in a corporate environment, there may be many reasons why you need to protect the programs, data, and settings on the computers. This article presents multiple ways of locking down a Windows 7 computer, depending on the type of usage being employed by the users. You may need to use a combination of several of the following methods to protect your programs, data, and settings. How to Stress Test the Hard Drives in Your PC or Server How To Customize Your Android Lock Screen with WidgetLocker The Best Free Portable Apps for Your Flash Drive Toolkit

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  • WCF/ADO.NET Data Services - Could not load type 'System.Data.Services.Providers.IDataServiceUpdatePr

    - by Sahil Malik
    Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). When you try accessing ListData.svc, do you get the following error? Could not load type 'System.Data.Services.Providers.IDataServiceUpdateProvider' from assembly 'System.Data.Services, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. Well, if you followed the instructions in Chapter 1 of my book to build your VM, you wouldn’t run into the above issue. But if you do, you need to install  -   For Windows Vista and Windows 2008 - http://www.microsoft.com/downloads/details.aspx?familyid=4B710B89-8576-46CF-A4BF-331A9306D555&displaylang=en For Windows 7 and Windows 2008 R2 - http://www.microsoft.com/downloads/details.aspx?familyid=79d7f6f8-d6e9-4b8c-8640-17f89452148e&displaylang=en Remember to: a) Install the x64 version, and b) Do an IISReset before trying again. Comment on the article ....

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  • SQL SERVER – Integration Services Balanced Data Distributor – SSIS Balanced Data Distributor

    - by pinaldave
    Microsoft SSIS Balanced Data Distributor (BDD) is a new SSIS transform. This transform takes a single input and distributes the incoming rows to one or more outputs uniformly via multithreading. The transform takes one pipeline buffer worth of rows at a time and moves it to the next output in a round robin fashion. It’s balanced and synchronous so if one of the downstream transforms or destinations is slower than the others, the rest of the pipeline will stall so this transform works best if all of the outputs have identical transforms and destinations. Download SQL Server Integration Services Balanced Data Distributor Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Yes, you can benefit from both data and backup compression

    - by AaronBertrand
    Earlier today, MSSQLTips posted a backup compression tip by Thomas LaRock ( blog | twitter ). In that article, Tom states: "If you are already compressing data then you will not see much benefit from backup compression." I don't want to argue with a rock star, and I will concede that he may be right in some scenarios. Nonetheless, I tweeted that "it depends;" Thomas then asked for "an example where you have data comp and you also see a large benefit from backup comp?" My initial reaction came about...(read more)

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  • Update/Insert With ADF Web Service Data Control

    - by shay.shmeltzer
    The Web service data control (WSDC) in ADF is a powerful feature that allows you to easily build a UI on top of WS interfaces exposed by other systems. However when you drag a WSDC to a page you usually get a set of output components where the data is shown. So how would you actually do an update operation on those values? The answer is that you need a call to another method in your WSDC that does the update - but what if you want to pass to it the actual values that you get from the get method you invoked before? Here is a demo showing how to do that: The two tricks that are shown here are: Changing the properties of items in the DC to be updateable - this gives you inputText fields instead of outputText fields. And passing the currentRow.dataProvider to the update method (and choosing the right iterator for this).

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  • Start your journey into Big Data with the Oracle Academy today!

    - by KLaker
     Big Data has the power to change the way we work, live, and think. The datafication of everything will create unprecedented demand for data scientists, software developers and engineers who can derive value from unstructured data to transform the world. The Oracle Academy Big Data Resource Guide is a collection of articles, videos, and other resources organized to help you gain a deeper understanding of the exciting field of Big Data. To start your journey visit the Oracle Academy website here: https://academy.oracle.com/oa-web-big-data.html. This landing pad will guide through the whole area of big data using the following structure: What is “Big Data” Engineered Systems Integration Database and Data Analytics Advanced Information Supplemental Information This is great resource packed with must-see videos and must-read whitepapers and blog posts by industry leaders.  Enjoy Technorati Tags: Big Data, Data Warehousing, Oracle, Training

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  • Moving large amounts of data between shared hosts

    - by Bryan M.
    I recently acquired a client who is a photographer and was interested in moving web hosts since his current host had threatened to throw him off due to CPU spiking. The migration went fairly easily, with about 350MBs of website and media files. Then I discovered about 60GBs of client galleries he had failed to mention. I am unable to move this much data myself, since I'm capping out at about 20kb/s on the FTP connection. Has anyone encountered a situation where they needed to migrate this much data between cheap hosting? Should we contact the hosting companies about this (he is moving from Westhost to MediaTemple)?

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  • Data Warehouse Workshop

    - by Davide Mauri
    I’m really really pleased to announce that it’s possible to register to the Data Warehouse Workshop that I and Thomas Kejser developed togheter.  Several months ago we decided to join forces in order to create a workshop that would contain not only the theoretical stuff, but also the experience we both have and all the best practices and lesson learned that can make the difference between a success and a failure when building a Data Warehouse. The first sheduled date is 7 February in Kista (Sweden): http://www.eventzilla.net/web/event?eventid=2138965081 and until 30th November there is the Super Early Bird to save more the 100€ (150$). The workshop will be very similar to the one I delivered at PASS Summit summit, with some extra technical stuff since it’s one hour longer. In addition to that for this first version both me and Thomas will be present, so it’s a great change  to make sure you super-charge your DW/BI project with insights that aren’t available anywhere else! If you’re into the BI field and you live in Europe, don’t miss this opportunity!

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  • What do I need to know about Data Structures and Algorithms in the "real" world

    - by Ray T Champion
    I just finished the data structures and algorithms course in school , I took it during the summer so 6wks course vs a 16 wk course during the regular semester. So not only was the course hard but it was really really really fast. My question is what do I need to know about data structures in the real world? I understand what they do and how they work, for the most part, but I had a real tough time coding them , I wouldn't be able to write the code for a binary tree class or a balanced tree class from scratch .... Is that bad? should I retake it , or is knowledge of how they work sufficient, without being able to write the classes from scratch?

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  • Coherence Data Guarantees for Data Reads - Basic Terminology

    - by jpurdy
    When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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  • Can data classes contain methods for validation?

    - by Arturas M
    OK, say I have a data class for a user: public class User { private String firstName; private String lastName; private long personCode; private Date birthDate; private Gender gender; private String email; private String password; Now let's say I want to validate email, whether names are not empty, whether birth date is in normal range, etc. Can I put that validation method in this class together with data? Or should it be in UserManager which in my case handles the lists of these users?

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  • How much data validation is too much? [closed]

    - by adbertram
    Possible Duplicate: Data input validation - Where? How much? I'm a new PHP developer and am into Powershell quite a bit but this question is language agnostic. I've been questioning my code quite a bit lately thinking about how many nets I should setup to catch exceptions, verify results, etc. I realize that I could go crazy trying to verify each and every line of code but at the same time I want the code as resilient as possible. I'm not talking about user input but verifying output from methods. Is there some standard or rule of thumb to go by when deciding when and where to do data validation?

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  • Data structure for file search

    - by poly
    I've asked this question before and I got a few answers/idea, but I'm not sure how to implement them. I'm building a telecom messaging solution. Currently, I'm using a database to save my transaction/messages for the network stack I've built, and as you know it's slower than using a data structure (hash, linkedlist, etc...). My problem is that the data can be really huge, and it won't fit in the memory. I was thinking of saving the records in a file and the a key and line number in a hash, then if I want to access some record then I can get the line number from the hash, and get it from the file. I don't know how efficient is this; I think the database is doing a way better job than this on my behalf. Please share whatever you have in mind.

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  • Answered: Selecting even table rows from a table element

    - by mvrak
    The issue I am having is: How do I go from a variable pointing at an element to using CSS selectors? I want to make this work: function highlight(table) {$(table " > :even").toggleClass('highlight');} where table is a reference to a table element. I don't want answers that tell me to use $('#table') because that defeats the point of the generality I am trying to make. Thanks

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  • Mysql table Crashed during Optimize, table repair taking too long

    - by hellohellosharp
    One of my vital tables was being optimzied and MySQL crashed in the middle of it. It then said the table was corrupt. I am running repair but it is taking over an hour, I need this table up ASAP (I will even truncate it if necessary). Please help me get this solved. The table has about 54 million rows. This is a MyISAM. Any additional information needed, just ask. Here are the contents of my my.cnf: [mysqld] max_connections = 850 max_user_connections = 850 query_cache_size = 128M skip-external-locking key_buffer_size = 64M max_allowed_packet = 8M table_open_cache = 256 sort_buffer_size = 4M net_buffer_length = 16K read_buffer_size = 1M read_rnd_buffer_size = 1M myisam_sort_buffer_size = 32M innodb_file_per_table tmp_table_size = 100M max_heap_table_size = 64M thread_cache_size = 8 wait_timeout=25 interactive_timeout=25 table_cache=600 innodb_buffer_pool_size = 4G innodb_thread_concurrency = 8 innodb_flush_method = O_DIRECT # This setting allows the use of asynchronous I/O in InnoDB. # The following files track usage of this resource: # - /proc/sys/fs/aio-max-nr # - /proc/sys/fs/aio-nr # Default limit is 65536, of which a single instance of mysql uses 2661 out of the box innodb_use_native_aio = 1

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  • Scrambling Sensitive Data in E-Business Suite Release 12 Cloned Environments

    - by Elke Phelps (Oracle Development)
    Securing the Oracle E-Business Suite includes protecting the underlying E-Business data in production and non-production databases.  While steps can be taken to provide a secure configuration to limit EBS access, a better approach to protecting non-production data is simply to scramble (mask) the data in the non-production copy.  You can use the Oracle Data Masking Pack with Oracle Enterprise Manager today to scramble sensitive data in cloned environments. Due to data dependencies, scrambling E-Business Suite data is not a trivial task.  The data needs to be scrubbed in such a way that allows the application to continue to function.  Using the Data Masking Pack in E-Business Suite environments is now easier with the release of new set of templates for E-Business Suite databases: Oracle E-Business Suite Release 12.1.3 Template for Data Masking Pack (Patch13898999) This template works with the Oracle Data Masking Pack and Oracle Enterprise Manager to obscure sensitive E-Business Suite information that is copied from production to non-production environments.  Is there a charge for this? Yes. You must purchase licenses for Oracle Enterprise Manager and the Oracle Data Masking Pack plug-in. The Oracle E-Business Suite 12.1.3 Template for the Data Masking Pack is included with the Oracle Data Masking Pack license.  You can contact your Oracle account manager for more details about licensing. What does data masking do in E-Business Suite environments? Application data masking does the following: De-identify the data:  Scramble identifiers of individuals, also known as personally identifiable information or PII.  Examples include information such as name, account, address, location, and driver's license number. Mask sensitive data:  Mask data that, if associated with personally identifiable information (PII), would cause privacy concerns.  Examples include compensation, health and employment information.   Maintain data validity:  Provide a fully functional application. How can EBS customers use data masking? The Oracle E-Business Suite Template for Data Masking Pack can be used in situations where confidential or regulated data needs to be shared with other non-production users who need access to some of the original data, but not necessarily every table.  Examples of non-production users include internal application developers or external business partners such as offshore testing companies, suppliers or customers.  The Oracle E-Business Suite Template for Data Masking Pack is applied to a non-production environment with the Enterprise Manager Grid Control Data Masking Pack.  When applied, the Oracle E-Business Suite Template for Data Masking Pack will create an irreversibly scrambled version of your production database for development and testing.   References For additional information on the Oracle E-Business Suite Template for Data Masking Pack please refer to the following: Masking Sensitive Data for Non-production Use in the Oracle Enterprise Manager Concepts 11g Using the Oracle E-Business Suite, Release 12.1.3 Template for the Data Masking Pack, Note 1437485.1 Related Articles Webcast Replay Available: E-Business Suite Data Protection Oracle E-Business Suite Plug-in 4.0 Released for OEM 11g (11.1.0.1)

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  • E-Business Suite 12.1.3 Data Masking Certified with Enterprise Manager 12c

    - by Elke Phelps (Oracle Development)
    Following up on our prior announcement for EM 11g, we're pleased to announce the certification of the E-Business Suite 12.1.3 Data Masking Template for the Data Masking Pack with Enterprise Manager Cloud Control 12c. You can use the Oracle Data Masking Pack with Oracle Enterprise Manager Grid Control 12c to scramble sensitive data in cloned E-Business Suite environments.  Due to data dependencies, scrambling E-Business Suite data is not a trivial task.  The data needs to be scrubbed in such a way that allows the application to continue to function.  You may scramble data in E-Business Suite cloned environments with EM12c using the following template: E-Business Suite 12.1.3 Data Masking Template for Data Masking Pack with EM12c (Patch 14407414) What does data masking do in E-Business Suite environments? Application data masking does the following: De-identify the data:  Scramble identifiers of individuals, also known as personally identifiable information or PII.  Examples include information such as name, account, address, location, and driver's license number. Mask sensitive data:  Mask data that, if associated with personally identifiable information (PII), would cause privacy concerns.  Examples include compensation, health and employment information.   Maintain data validity:  Provide a fully functional application. How can EBS customers use data masking? The Oracle E-Business Suite Template for Data Masking Pack can be used in situations where confidential or regulated data needs to be shared with other non-production users who need access to some of the original data, but not necessarily every table.  Examples of non-production users include internal application developers or external business partners such as offshore testing companies, suppliers or customers.  The template works with the Oracle Data Masking Pack and Oracle Enterprise Manager to obscure sensitive E-Business Suite information that is copied from production to non-production environments. The Oracle E-Business Suite Template for Data Masking Pack is applied to a non-production environment with the Enterprise Manager Grid Control Data Masking Pack.  When applied, the Oracle E-Business Suite Template for Data Masking Pack will create an irreversibly scrambled version of your production database for development and testing.  What's new with EM 12c? Some of the execution steps may also be performed with EM Command Line Interface (EM CLI).  Support of EM CLI is a new feature with the E-Business Suite Release 12.1.3 template for EM 12c.  Is there a charge for this? Yes. You must purchase licenses for the Oracle Data Masking Pack plug-in. The Oracle E-Business Suite 12.1.3 Template for the Data Masking Pack is included with the Oracle Data Masking Pack license.  You can contact your Oracle account manager for more details about licensing. References Additional details and requirements are provided in the following My Oracle Support Note: Using Oracle E-Business Suite Release 12.1.3 Template for the Data Masking Pack with Oracle Enterprise Manager 12.1.0.2 Data Masking Tool (Note 1481916.1) Masking Sensitive Data in the Oracle Database Real Application Testing User's Guide 11g Release 2 (11.2) Related Articles Scrambling Sensitive Data in E-Business Suite

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