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  • Core Data strategy using in memory cache, or no core data at all?

    - by randombits
    I have a user interface where the user can check off a bunch of items from a tableview, almost like a todo list. The items are populated from a Core Data stack. I need to be able to take all of the items they're clicking through and put them into a "temporary" shopping cart. Once they're in the shopping cart, users can go through the list and remove the items, or just submit them to a server. The thing is, the selected items are temporary just like an internet based shopping cart. It's nothing something that gets persisted once the application closes. Once the view is no longer in display, I can assume that the shopping cart is safe to discard. What's the best way to approach this? Since the user is essentially clicking on instances that map back to a Core Data entity .. should I setup a different persistence store such as in memory and add that store to my managed object context?

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  • Help choosing the right data structure

    - by devoured elysium
    I need a data structure with the following requirements: Needs to be able to get elements by index (like a List). I will always just add / remove elements from the end of the structure. I am inclined to use an ArrayList. In this situation, it seems to be O(1) both to read elements (they always are?), remove elements (I only need to remove them at the end of the list) and to add(I only add to the end of the list). There is only the problem that time to time the ArrayList will have a performance penalty when it's completly full and I need to add more elements to it. Is there any other better idea? I don't think of a data structure that'd beat the ArrayList here. Thanks

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  • Store data in Ruby on Rails without Database

    - by snowmaninthesun
    I have a few data values that I need to store on my rails app and wanted to know if there are any alternatives to creating a database table just to do this simple task. Background: I'm writing some analytics and dashboard tools for my ruby on rails app and i'm hoping to speed up the dashboard by caching results that will never change. Right now I pull all users for the last 30 days, and re arange them so I can see the number of new users per day. It works great but takes quite a long time, in reality I should only need to calculate the most recent day and just store the rest of the array somewhere else. Where is the best way to store this array? Creating a database table seems a bit overkill, and i'm not sure that global variables are the correct answer. Is there a best practice for persisting data like this? If anyone has done anything like this before let me know what you did and how it turned out.

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  • Designing DAOs for data sources other than a database

    - by James P.
    Hi, Until now I've been used to using DAOs to retrieve information from databases. Other sources of data are possible though and I'm wondering if and how the pattern could be applied in general. For example, I'm now working on an application that fetches XML on the web. The XML file could be considered as a data source and the actual fetching is similar in principle to a database request. I'm not quite sure how the DAO could be structured though. Any views on the subject are welcome.

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  • Programming DataEntry&Forms: Population of Official Common Data Lists

    - by rlb.usa
    As a programmer of data-entry forms of all kinds, I often find myself making fields for things like Country and State. Consider: Perhaps a list the 50 United States names is an easy thing to find (does one include DC?) , but the countries are not. Nearly every site you find has a differing list with all of the political goings on over the years, and they become outdated quickly. What's the best practice regarding population of these kinds of lists? Is there an official list somewhere that one uses to populate these kinds of formal/official fields? Where do you get this data from, when it's not exactly specified in the specs?

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  • Store image in core data and Retina Display ?

    - by shani
    Hi I have an app that has hundreds of words with 3/4 images for each word. I have 2 versions of each word one for iOS 3 and one for retina display. I wish to save the images as data and connect them to the appropriate word so it will be easy to pull them later. my question is - how do i get the suitable size ? its works great with the @2x wjen you get it from the app file system, but hoe does it supposed to work when i get it from data ? thanks shani

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  • Entity Framework 4 & WCF Data Service: N:M mapping

    - by JJO
    I have three tables in my database: An A table, a B table, and a many-to-many ABMapping table. For simplicity, A and B are keyed with identity columns; ABMapping has just two columns: AId and BId. I built an Entity Framework 4 model from this, and it did correctly identify the N:M mapping between A and B. I then built a WCF Data Service based on this EF model. I'm trying to consume this WCF Data Service. Unfortunately, I can't figure out how to get a mapping between As and Bs to map back to the database. I've tried something like this: A a = new A(); B b = new B(); a.Bs.Add(b); connection.SaveChanges(); But this doesn't seem to have worked. Any clues? What am I missing?

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  • Twin edges - Half edge data structure

    - by Pradeep Kumar
    I have implemented a Half-edge data structure for loading 3d objects. I find that the part of assigning twin/pair edges takes the longest computation time (especially for objects which have hundreds of thousands half edges). The reason is that I use nested loops to accomplish this. Is there a simpler and efficient way of doing this? Below is the code which I've written. HE is the half-edge data structure. hearr is a vector containing all the half edges. vert is the starting vertex and end is the ending vertex. Thanks!! HE *e1,*e2; for(size_t i=0;i<hearr.size();i++){ e1=hearr[i]; for(size_t j=1;j<hearr.size();j++){ e2=hearr[j]; if((e1->vert==e2->end)&&(e2->vert==e1->end)){ e1->twin=e2; e2->twin=e1; } } }

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  • How to copy a structure with pointers to data inside (so to copy pointers and data they point to)?

    - by Kabumbus
    so I have a structure like struct GetResultStructure { int length; char* ptr; }; I need a way to make a full copy of it meaning I need a copy to have a structure with new ptr poinnting on to copy of data I had in original structure. Is It any how possible? I mean any structure I have which contains ptrs will have some fields with its lengths I need a function that would copy my structure coping all ptrs and data they point to by given array of lengthes... Any cool boost function for it? Or any way how to create such function?

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  • Where does one get data like Country:(list) State:(list)

    - by rlb.usa
    As a programmer of data-entry forms of all kinds, I often find myself making fields for things like Country: <choose from list>, State: <choose from list>, Race/Ethnicity: <choose from list>. Consider: Perhaps a list the 50 United States names is an easy thing to find (does one include DC?) , but the countries are not. Nearly every site you find has a differing list with all of the political goings on over the years, and they become outdated quickly. What's the best/common practice regarding population of these kinds of lists? Where does this data come from if it's not given in the specs?

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  • The data structure of libev watchers

    - by changchang
    Libev uses three data structures to storage different watchers. Heap: for watchers that sorted by time, such as ev_timer and ev_periodic. Linked list: such as ev_io, ev_signal, ev_child and etc. Array: such as ev_prepare, ev_check, ev_async and etc. There is no doubt about that uses heap to store timer watcher. But what is the criteria of selecting linked list and array? The data structure that stores ev_io watchers seems a little complex. It first is an array that with fd as its index and the element in the array is a linked list of ev_io watcher. It is more convenient to allocate space for array if use linked list as element. Is it the reason? Or just because of the insert or remove operation of ev_io is more frequently and the ev_prepare seems more stable? Or any other reasons?

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  • Manipulate data for scaling

    - by user1487000
    I have this data: Game 1: 7.0/10.0, Reviewed: 1000 times Game 2: 7.5/10.0, Reviewed: 3000 times Game 3: 8.9/10.0, Reviewed: 140,000 times Game 4: 10.0/10.0 Reviewed: 5 times . . . I want to manipulate this data in a way to make each rating reflective of how many times it has been reviewed. For example Game 3 should have a little heavier weight than than Game 4, since it has been reviewed way more. And Game 2's 7 should be weighted more than Game 1's 7. Is there a proper function to do this scaling? In such a way that ScaledGameRating = OldGameRating * (some exponential function?)

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  • Fragmented Log files could be slowing down your database

    - by Fatherjack
    Something that is sometimes forgotten by a lot of DBAs is the fact that database log files get fragmented in the same way that you get fragmentation in a data file. The cause is very different but the effect is the same – too much effort reading and writing data. Data files get fragmented as data is changed through normal system activity, INSERTs, UPDATEs and DELETEs cause fragmentation and most experienced DBAs are monitoring their indexes for fragmentation and dealing with it accordingly. However, you don’t hear about so many working on their log files. How can a log file get fragmented? I’m glad you asked. When you create a database there are at least two files created on the disk storage; an mdf for the data and an ldf for the log file (you can also have ndf files for extra data storage but that’s off topic for now). It is wholly possible to have more than one log file but in most cases there is little point in creating more than one as the log file is written to in a ‘wrap-around’ method (more on that later). When a log file is created at the time that a database is created the file is actually sub divided into a number of virtual log files (VLFs). The number and size of these VLFs depends on the size chosen for the log file. VLFs are also created in the space added to a log file when a log file growth event takes place. Do you have your log files set to auto grow? Then you have potentially been introducing many VLFs into your log file. Let’s get to see how many VLFs we have in a brand new database. USE master GO CREATE DATABASE VLF_Test ON ( NAME = VLF_Test, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test.mdf', SIZE = 100, MAXSIZE = 500, FILEGROWTH = 50 ) LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5MB, MAXSIZE = 250MB, FILEGROWTH = 5MB ); go USE VLF_Test go DBCC LOGINFO; The results of this are firstly a new database is created with specified files sizes and the the DBCC LOGINFO results are returned to the script editor. The DBCC LOGINFO results have plenty of interesting information in them but lets first note there are 4 rows of information, this relates to the fact that 4 VLFs have been created in the log file. The values in the FileSize column are the sizes of each VLF in bytes, you will see that the last one to be created is slightly larger than the others. So, a 5MB log file has 4 VLFs of roughly 1.25 MB. Lets alter the CREATE DATABASE script to create a log file that’s a bit bigger and see what happens. Alter the code above so that the log file details are replaced by LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 1GB, MAXSIZE = 25GB, FILEGROWTH = 1GB ); With a bigger log file specified we get more VLFs What if we make it bigger again? LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5GB, MAXSIZE = 250GB, FILEGROWTH = 5GB ); This time we see more VLFs are created within our log file. We now have our 5GB log file comprised of 16 files of 320MB each. In fact these sizes fall into all the ranges that control the VLF creation criteria – what a coincidence! The rules that are followed when a log file is created or has it’s size increased are pretty basic. If the file growth is lower than 64MB then 4 VLFs are created If the growth is between 64MB and 1GB then 8 VLFs are created If the growth is greater than 1GB then 16 VLFs are created. Now the potential for chaos comes if the default values and settings for log file growth are used. By default a database log file gets a 1MB log file with unlimited growth in steps of 10%. The database we just created is 6 MB, let’s add some data and see what happens. USE vlf_test go -- we need somewhere to put the data so, a table is in order IF OBJECT_ID('A_Table') IS NOT NULL DROP TABLE A_Table go CREATE TABLE A_Table ( Col_A int IDENTITY, Col_B CHAR(8000) ) GO -- Let's check the state of the log file -- 4 VLFs found EXECUTE ('DBCC LOGINFO'); go -- We can go ahead and insert some data and then check the state of the log file again INSERT A_Table (col_b) SELECT TOP 500 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO -- insert 500 rows and we get 22 VLFs EXECUTE ('DBCC LOGINFO'); go -- Let's insert more rows INSERT A_Table (col_b) SELECT TOP 2000 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO 10 -- insert 2000 rows, in 10 batches and we suddenly have 107 VLFs EXECUTE ('DBCC LOGINFO'); Well, that escalated quickly! Our log file is split, internally, into 107 fragments after a few thousand inserts. The same happens with any logged transactions, I just chose to illustrate this with INSERTs. Having too many VLFs can cause performance degradation at times of database start up, log backup and log restore operations so it’s well worth keeping a check on this property. How do we prevent excessive VLF creation? Creating the database with larger files and also with larger growth steps and actively choosing to grow your databases rather than leaving it to the Auto Grow event can make sure that the growths are made with a size that is optimal. How do we resolve a situation of a database with too many VLFs? This process needs to be done when the database is under little or no stress so that you don’t affect system users. The steps are: BACKUP LOG YourDBName TO YourBackupDestinationOfChoice Shrink the log file to its smallest possible size DBCC SHRINKFILE(FileNameOfTLogHere, TRUNCATEONLY) * Re-size the log file to the size you want it to, taking in to account your expected needs for the coming months or year. ALTER DATABASE YourDBName MODIFY FILE ( NAME = FileNameOfTLogHere, SIZE = TheSizeYouWantItToBeIn_MB) * – If you don’t know the file name of your log file then run sp_helpfile while you are connected to the database that you want to work on and you will get the details you need. The resize step can take quite a while This is already detailed far better than I can explain it by Kimberley Tripp in her blog 8-Steps-to-better-Transaction-Log-throughput.aspx. The result of this will be a log file with a VLF count according to the bullet list above. Knowing when VLFs are being created By complete coincidence while I have been writing this blog (it’s been quite some time from it’s inception to going live) Jonathan Kehayias from SQLSkills.com has written a great article on how to track database file growth using Event Notifications and Service Broker. I strongly recommend taking a look at it as this is going to catch any sneaky auto grows that take place and let you know about them right away. Hassle free monitoring of VLFs If you are lucky or wise enough to be using SQL Monitor or another monitoring tool that let’s you write your own custom metrics then you can keep an eye on this very easily. There is a custom metric for VLFs (written by Stuart Ainsworth) already on the site and there are some others there are very useful so take a moment or two to look around while you are there. Resources MSDN – http://msdn.microsoft.com/en-us/library/ms179355(v=sql.105).aspx Kimberly Tripp from SQLSkills.com – http://www.sqlskills.com/BLOGS/KIMBERLY/post/8-Steps-to-better-Transaction-Log-throughput.aspx Thomas LaRock at Simple-Talk.com – http://www.simple-talk.com/sql/database-administration/monitoring-sql-server-virtual-log-file-fragmentation/ Disclosure I am a Friend of Red Gate. This means that I am more than likely to say good things about Red Gate DBA and Developer tools. No matter how awesome I make them sound, take the time to compare them with other products before you contact the Red Gate sales team to make your order.

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  • A Custom View Engine with Dynamic View Location

    - by imran_ku07
        Introduction:          One of the nice feature of ASP.NET MVC framework is its pluggability. This means you can completely replace the default view engine(s) with a custom one. One of the reason for using a custom view engine is to change the default views location and sometimes you need to change the views location at run-time. For doing this, you can extend the default view engine(s) and then change the default views location variables at run-time.  But, you cannot directly change the default views location variables at run-time because they are static and shared among all requests. In this article, I will show you how you can dynamically change the views location without changing the default views location variables at run-time.       Description:           Let's say you need to synchronize the views location with controller name and controller namespace. So, instead of searching to the default views location(Views/ControllerName/ViewName) to locate views, this(these) custom view engine(s) will search in the Views/ControllerNameSpace/ControllerName/ViewName folder to locate views.           First of all create a sample ASP.NET MVC 3 application and then add these custom view engines to your application,   public class MyRazorViewEngine : RazorViewEngine { public MyRazorViewEngine() : base() { AreaViewLocationFormats = new[] { "~/Areas/{2}/Views/%1/{1}/{0}.cshtml", "~/Areas/{2}/Views/%1/{1}/{0}.vbhtml", "~/Areas/{2}/Views/%1/Shared/{0}.cshtml", "~/Areas/{2}/Views/%1/Shared/{0}.vbhtml" }; AreaMasterLocationFormats = new[] { "~/Areas/{2}/Views/%1/{1}/{0}.cshtml", "~/Areas/{2}/Views/%1/{1}/{0}.vbhtml", "~/Areas/{2}/Views/%1/Shared/{0}.cshtml", "~/Areas/{2}/Views/%1/Shared/{0}.vbhtml" }; AreaPartialViewLocationFormats = new[] { "~/Areas/{2}/Views/%1/{1}/{0}.cshtml", "~/Areas/{2}/Views/%1/{1}/{0}.vbhtml", "~/Areas/{2}/Views/%1/Shared/{0}.cshtml", "~/Areas/{2}/Views/%1/Shared/{0}.vbhtml" }; ViewLocationFormats = new[] { "~/Views/%1/{1}/{0}.cshtml", "~/Views/%1/{1}/{0}.vbhtml", "~/Views/%1/Shared/{0}.cshtml", "~/Views/%1/Shared/{0}.vbhtml" }; MasterLocationFormats = new[] { "~/Views/%1/{1}/{0}.cshtml", "~/Views/%1/{1}/{0}.vbhtml", "~/Views/%1/Shared/{0}.cshtml", "~/Views/%1/Shared/{0}.vbhtml" }; PartialViewLocationFormats = new[] { "~/Views/%1/{1}/{0}.cshtml", "~/Views/%1/{1}/{0}.vbhtml", "~/Views/%1/Shared/{0}.cshtml", "~/Views/%1/Shared/{0}.vbhtml" }; } protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.CreatePartialView(controllerContext, partialPath.Replace("%1", nameSpace)); } protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.CreateView(controllerContext, viewPath.Replace("%1", nameSpace), masterPath.Replace("%1", nameSpace)); } protected override bool FileExists(ControllerContext controllerContext, string virtualPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.FileExists(controllerContext, virtualPath.Replace("%1", nameSpace)); } } public class MyWebFormViewEngine : WebFormViewEngine { public MyWebFormViewEngine() : base() { MasterLocationFormats = new[] { "~/Views/%1/{1}/{0}.master", "~/Views/%1/Shared/{0}.master" }; AreaMasterLocationFormats = new[] { "~/Areas/{2}/Views/%1/{1}/{0}.master", "~/Areas/{2}/Views/%1/Shared/{0}.master", }; ViewLocationFormats = new[] { "~/Views/%1/{1}/{0}.aspx", "~/Views/%1/{1}/{0}.ascx", "~/Views/%1/Shared/{0}.aspx", "~/Views/%1/Shared/{0}.ascx" }; AreaViewLocationFormats = new[] { "~/Areas/{2}/Views/%1/{1}/{0}.aspx", "~/Areas/{2}/Views/%1/{1}/{0}.ascx", "~/Areas/{2}/Views/%1/Shared/{0}.aspx", "~/Areas/{2}/Views/%1/Shared/{0}.ascx", }; PartialViewLocationFormats = ViewLocationFormats; AreaPartialViewLocationFormats = AreaViewLocationFormats; } protected override IView CreatePartialView(ControllerContext controllerContext, string partialPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.CreatePartialView(controllerContext, partialPath.Replace("%1", nameSpace)); } protected override IView CreateView(ControllerContext controllerContext, string viewPath, string masterPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.CreateView(controllerContext, viewPath.Replace("%1", nameSpace), masterPath.Replace("%1", nameSpace)); } protected override bool FileExists(ControllerContext controllerContext, string virtualPath) { var nameSpace = controllerContext.Controller.GetType().Namespace; return base.FileExists(controllerContext, virtualPath.Replace("%1", nameSpace)); } }             Here, I am extending the RazorViewEngine and WebFormViewEngine class and then appending /%1 in each views location variable, so that we can replace /%1 at run-time. I am also overriding the FileExists, CreateView and CreatePartialView methods. In each of these method implementation, I am replacing /%1 with controller namespace. Now, just register these view engines in Application_Start method in Global.asax.cs file,   protected void Application_Start() { ViewEngines.Engines.Clear(); ViewEngines.Engines.Add(new MyRazorViewEngine()); ViewEngines.Engines.Add(new MyWebFormViewEngine()); ................................................ ................................................ }             Now just create a controller and put this controller's view inside Views/ControllerNameSpace/ControllerName folder and then run this application. You will find that everything works just fine.       Summary:          ASP.NET MVC uses convention over configuration to locate views. For many applications this convention to locate views is acceptable. But sometimes you may need to locate views at run-time. In this article, I showed you how you can dynamically locate your views by using a custom view engine. I am also attaching a sample application. Hopefully you will enjoy this article too. SyntaxHighlighter.all()  

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  • Implementing a Custom Coherence PartitionAssignmentStrategy

    - by jpurdy
    A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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  • Records not being saved to core data sqlite file

    - by esd100
    I'm a complete newbie when it comes to iOS programming and much less Core Data. It's rather non-intuitive for me, as I really came into my own with programming with MATLAB, which I guess is more of a 'scripting' language. At any rate, my problem is that I had no idea what I had to do to create a database for my application. So I read a little bit and thought I had to create a SQL database of my stuff and then import it. Long story short, I created a SQLite db and I want to use the work I have already done to import stuff into my CoreData database. I tried exporting to comma-delimited files and xml files and reading those in, but I didn't like it and it seemed like an extra step that I shouldn't need to do. So, I imported the SQLite database into my resources and added the sqlite framework. I have my core data model setup and it is setting up the SQLite database for the model correctly in the background. When I run through my program to add objects to my entities, it seems to work and I can even fetch results afterward. However, when I inspect the Core Data Database SQLite file, no records have been saved. How is it possible for it to fetch results but not save them to the database? - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ //load in the path for resources NSString *paths = [[NSBundle mainBundle] resourcePath]; NSString *databaseName = @"histology.sqlite"; NSString *databasePath = [paths stringByAppendingPathComponent:databaseName]; [self createDatabase:databasePath ]; NSError *error; if ([[self managedObjectContext] save:&error]) { NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]); } // Test listing all CELLS from the store NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entityMO = [NSEntityDescription entityForName:@"CELL" inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entityMO]; NSArray *fetchedObjects = [[self managedObjectContext] executeFetchRequest:fetchRequest error:&error]; for (CELL *cellName in fetchedObjects) { //NSLog(@"cellName: %@", cellName); } -(void) createDatabase:databasePath { NSLog(@"The createDatabase function was entered."); NSLog(@"The databasePath is %@ ",[databasePath description]); // Setup the database object sqlite3 *histoDatabase; // Open the database from filessytem if(sqlite3_open([databasePath UTF8String], &histoDatabase) == SQLITE_OK) { NSLog(@"The database was opened"); // Setup the SQL Statement and compile it for faster access const char *sqlStatement = "SELECT * FROM CELL"; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(histoDatabase, sqlStatement, -1, &compiledStatement, NULL) != SQLITE_OK) { NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(histoDatabase)); } if(sqlite3_prepare_v2(histoDatabase, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { // Loop through the results and add them to cell MO array while(sqlite3_step(compiledStatement) == SQLITE_ROW) { CELL *cellMO = [NSEntityDescription insertNewObjectForEntityForName:@"CELL" inManagedObjectContext:[self managedObjectContext]]; if (sqlite3_column_type(compiledStatement, 0) != SQLITE_NULL) { cellMO.cellName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)]; } else { cellMO.cellName = @"undefined"; } if (sqlite3_column_type(compiledStatement, 1) != SQLITE_NULL) { cellMO.cellDescription = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; } else { cellMO.cellDescription = @"undefined"; } NSLog(@"The contents of NSString *cellName = %@",[cellMO.cellName description]); } } // Release the compiled statement from memory sqlite3_finalize(compiledStatement); } sqlite3_close(histoDatabase); } I have a feeling that it has something to do with the timing of opening/closing both of the databases? Attached I have some SQL debugging output to the terminal 2012-05-28 16:03:39.556 MedPix[34751:fb03] The createDatabase function was entered. 2012-05-28 16:03:39.557 MedPix[34751:fb03] The databasePath is /Users/jack/Library/Application Support/iPhone Simulator/5.1/Applications/A6B2A79D-BA93-4E24-9291-5B7948A3CDF4/MedPix.app/histology.sqlite 2012-05-28 16:03:39.559 MedPix[34751:fb03] The database was opened 2012-05-28 16:03:39.560 MedPix[34751:fb03] The database was prepared 2012-05-28 16:03:39.575 MedPix[34751:fb03] CoreData: annotation: Connecting to sqlite database file at "/Users/jack/Library/Application Support/iPhone Simulator/5.1/Applications/A6B2A79D-BA93-4E24-9291-5B7948A3CDF4/Documents/MedPix.sqlite" 2012-05-28 16:03:39.576 MedPix[34751:fb03] CoreData: annotation: creating schema. 2012-05-28 16:03:39.577 MedPix[34751:fb03] CoreData: sql: pragma page_size=4096 2012-05-28 16:03:39.578 MedPix[34751:fb03] CoreData: sql: pragma auto_vacuum=2 2012-05-28 16:03:39.630 MedPix[34751:fb03] CoreData: sql: BEGIN EXCLUSIVE 2012-05-28 16:03:39.631 MedPix[34751:fb03] CoreData: sql: SELECT TBL_NAME FROM SQLITE_MASTER WHERE TBL_NAME = 'Z_METADATA' 2012-05-28 16:03:39.632 MedPix[34751:fb03] CoreData: sql: CREATE TABLE ZCELL ( Z_PK INTEGER PRIMARY KEY, Z_ENT INTEGER, Z_OPT INTEGER, ZCELLDESCRIPTION VARCHAR, ZCELLNAME VARCHAR ) ... 2012-05-28 16:03:39.669 MedPix[34751:fb03] CoreData: annotation: Creating primary key table. 2012-05-28 16:03:39.671 MedPix[34751:fb03] CoreData: sql: CREATE TABLE Z_PRIMARYKEY (Z_ENT INTEGER PRIMARY KEY, Z_NAME VARCHAR, Z_SUPER INTEGER, Z_MAX INTEGER) 2012-05-28 16:03:39.672 MedPix[34751:fb03] CoreData: sql: INSERT INTO Z_PRIMARYKEY(Z_ENT, Z_NAME, Z_SUPER, Z_MAX) VALUES(1, 'CELL', 0, 0) ... 2012-05-28 16:03:39.701 MedPix[34751:fb03] CoreData: sql: CREATE TABLE Z_METADATA (Z_VERSION INTEGER PRIMARY KEY, Z_UUID VARCHAR(255), Z_PLIST BLOB) 2012-05-28 16:03:39.702 MedPix[34751:fb03] CoreData: sql: SELECT TBL_NAME FROM SQLITE_MASTER WHERE TBL_NAME = 'Z_METADATA' 2012-05-28 16:03:39.703 MedPix[34751:fb03] CoreData: sql: DELETE FROM Z_METADATA WHERE Z_VERSION = ? 2012-05-28 16:03:39.704 MedPix[34751:fb03] CoreData: sql: INSERT INTO Z_METADATA (Z_VERSION, Z_UUID, Z_PLIST) VALUES (?, ?, ?) 2012-05-28 16:03:39.705 MedPix[34751:fb03] CoreData: sql: COMMIT 2012-05-28 16:03:39.710 MedPix[34751:fb03] CoreData: sql: pragma cache_size=200 2012-05-28 16:03:39.711 MedPix[34751:fb03] CoreData: sql: SELECT Z_VERSION, Z_UUID, Z_PLIST FROM Z_METADATA 2012-05-28 16:03:39.712 MedPix[34751:fb03] The contents of NSString *cellName = Beta Cell 2012-05-28 16:03:39.712 MedPix[34751:fb03] The contents of NSString *cellName = Gastric Chief Cell ... 2012-05-28 16:03:39.714 MedPix[34751:fb03] The database was prepared 2012-05-28 16:03:39.764 MedPix[34751:fb03] The createDatabase function has finished. Now fetching. 2012-05-28 16:03:39.765 MedPix[34751:fb03] CoreData: sql: SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCELLDESCRIPTION, t0.ZCELLNAME FROM ZCELL t0 2012-05-28 16:03:39.766 MedPix[34751:fb03] CoreData: annotation: sql connection fetch time: 0.0008s 2012-05-28 16:03:39.767 MedPix[34751:fb03] CoreData: annotation: total fetch execution time: 0.0016s for 0 rows. 2012-05-28 16:03:39.768 MedPix[34751:fb03] cellName: <CELL: 0x6bbc120> (entity: CELL; id: 0x6bbc160 <x-coredata:///CELL/t57D10DDD-74E2-474F-97EE-E3BD0FF684DA34> ; data: { cellDescription = "S cells are cells which release secretin, found in the jejunum and duodenum. They are stimulated by a drop in pH to 4 or below in the small intestine's lumen. The released secretin will increase the s"; cellName = "S Cell"; organs = ( ); specimens = ( ); systems = ( ); tissues = ( ); }) ... Sections were cut short to abbreviate. But note that the fetch results contain information, but it says that total fetch execution was for "0" rows? How can that be? Any help will be greatly appreciated, especially detailed explanations. :) Thanks.

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  • data validation on wpf passwordbox:type password, re-type password

    - by black sensei
    Hello Experts !! I've built a wpf windows application in with there is a registration form. Using IDataErrorInfo i could successfully bind the field to a class property and with the help of styles display meaningful information about the error to users.About the submit button i use the MultiDataTrigger with conditions (Based on a post here on stackoverflow).All went well. Now i need to do the same for the passwordbox and apparently it's not as straight forward.I found on wpftutorial an article and gave it a try but for some reason it wasn't working. i've tried another one from functionalfun. And in this Functionalfun case the properties(databind,databound) are not recognized as dependencyproperty even after i've changed their name as suggested somewhere in the comments plus i don't have an idea whether it will work for a windows application, since it's designed for web. to give you an idea here is some code on textboxes <Window.Resources> <data:General x:Key="recharge" /> <Style x:Key="validButton" TargetType="{x:Type Button}" BasedOn="{StaticResource {x:Type Button}}" > <Setter Property="IsEnabled" Value="False"/> <Style.Triggers> <MultiDataTrigger> <MultiDataTrigger.Conditions> <Condition Binding="{Binding ElementName=txtRecharge, Path=(Validation.HasError)}" Value="false" /> </MultiDataTrigger.Conditions> <Setter Property="IsEnabled" Value="True" /> </MultiDataTrigger> </Style.Triggers> </Style> <Style x:Key="txtboxerrors" TargetType="{x:Type TextBox}" BasedOn="{StaticResource {x:Type TextBox}}"> <Style.Triggers> <Trigger Property="Validation.HasError" Value="true"> <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}"/> <Setter Property="Validation.ErrorTemplate"> <Setter.Value> <ControlTemplate> <DockPanel LastChildFill="True"> <TextBlock DockPanel.Dock="Bottom" FontSize="8" FontWeight="ExtraBold" Foreground="red" Padding="5 0 0 0" Text="{Binding ElementName=showerror, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"></TextBlock> <Border BorderBrush="Red" BorderThickness="2"> <AdornedElementPlaceholder Name="showerror" /> </Border> </DockPanel> </ControlTemplate> </Setter.Value> </Setter> </Trigger> </Style.Triggers> </Style> </Window.Resources> <TextBox Margin="12,69,12,70" Name="txtRecharge" Style="{StaticResource txtboxerrors}"> <TextBox.Text> <Binding Path="Field" Source="{StaticResource recharge}" ValidatesOnDataErrors="True" UpdateSourceTrigger="PropertyChanged"> <Binding.ValidationRules> <ExceptionValidationRule /> </Binding.ValidationRules> </Binding> </TextBox.Text> </TextBox> <Button Height="23" Margin="98,0,0,12" Name="btnRecharge" VerticalAlignment="Bottom" Click="btnRecharge_Click" HorizontalAlignment="Left" Width="75" Style="{StaticResource validButton}">Recharge</Button> some C# : class General : IDataErrorInfo { private string _field; public string this[string columnName] { get { string result = null; if(columnName == "Field") { if(Util.NullOrEmtpyCheck(this._field)) { result = "Field cannot be Empty"; } } return result; } } public string Error { get { return null; } } public string Field { get { return _field; } set { _field = value; } } } So what are suggestion you guys have for me? I mean how would you go about this? how do you do this since the databinding first purpose here is not to load data onto the fields they are just (for now) for data validation. thanks for reading this.

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  • How to populate a core data store programmatically?

    - by jdmuys
    I have ran out of hairs to pull with a crash in this routine that populates a core data store from a 9000+ line plist file. The crash happened at the very end of the routine inside the call to [managedObjectContext save:&error]. While if I save after every object insertion, the crash doesn't happen. Of course, saving after every object insertion totally kills the performance (from less than a second to many minutes). I modified my code so that it saves every K insertions, and the crash happens as soon as K = 2. The crash is an out-of-bound exception for an NSArray: Serious application error. Exception was caught during Core Data change processing: *** -[NSCFArray objectAtIndex:]: index (1) beyond bounds (1) with userInfo (null) Also maybe relevant, when the exception happen, my fetch result controller controllerDidChangeContent: delegate routine is in the call stack. It simply calls my table view endUpdate routine. I am now running out of ideas. How am I supposed to populate a core data store with a table view? Here is the call stack: #0 0x901ca4e6 in objc_exception_throw #1 0x01d86c3b in +[NSException raise:format:arguments:] #2 0x01d86b9a in +[NSException raise:format:] #3 0x00072cb9 in _NSArrayRaiseBoundException #4 0x00010217 in -[NSCFArray objectAtIndex:] #5 0x002eaaa7 in -[UITableView(_UITableViewPrivate) _endCellAnimationsWithContext:] #6 0x002def02 in -[UITableView endUpdates] #7 0x00004863 in -[AirportViewController controllerDidChangeContent:] at AirportViewController.m:463 #8 0x01c43be1 in -[NSFetchedResultsController(PrivateMethods) _managedObjectContextDidChange:] #9 0x0001462a in _nsnote_callback #10 0x01d31005 in _CFXNotificationPostNotification #11 0x00011ee0 in -[NSNotificationCenter postNotificationName:object:userInfo:] #12 0x01ba417d in -[NSManagedObjectContext(_NSInternalNotificationHandling) _postObjectsDidChangeNotificationWithUserInfo:] #13 0x01c03763 in -[NSManagedObjectContext(_NSInternalChangeProcessing) _createAndPostChangeNotification:withDeletions:withUpdates:withRefreshes:] #14 0x01b885ea in -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] #15 0x01bbe728 in -[NSManagedObjectContext save:] #16 0x000039ea in -[AirportViewController populateAirports] at AirportViewController.m:112 Here is the code to the routine. I apologize because a number of lines are probably irrelevant, but I'd rather err on that side. The crash happens the very first time it calls [managedObjectContext save:&error]: - (void) populateAirports { NSBundle *meBundle = [NSBundle mainBundle]; NSString *dbPath = [meBundle pathForResource:@"DuckAirportsBin" ofType:@"plist"]; NSArray *initialAirports = [[NSArray alloc] initWithContentsOfFile:dbPath]; //********************************************************************************* // get existing countries NSMutableDictionary *countries = [[NSMutableDictionary alloc] initWithCapacity:200]; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Country" inManagedObjectContext:managedObjectContext]; [fetchRequest setEntity:entity]; NSError *error = nil; NSArray *values = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; if (!values) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } int numCountries = [values count]; NSLog(@"We have %d countries in store", numCountries); for (Country *aCountry in values) { [countries setObject:aCountry forKey:aCountry.code]; } [fetchRequest release]; //********************************************************************************* // read airports int numAirports = 0; int numUnsavedAirports = 0; #define MAX_UNSAVED_AIRPORTS_BEFORE_SAVE 2 numCountries = 0; for (NSDictionary *anAirport in initialAirports) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSString *countryCode = [anAirport objectForKey:@"country"]; Country *thatCountry = [countries objectForKey:countryCode]; if (!thatCountry) { thatCountry = [NSEntityDescription insertNewObjectForEntityForName:@"Country" inManagedObjectContext:managedObjectContext]; thatCountry.code = countryCode; thatCountry.name = [anAirport objectForKey:@"country_name"]; thatCountry.population = 0; [countries setObject:thatCountry forKey:countryCode]; numCountries++; NSLog(@"Found %dth country %@=%@", numCountries, countryCode, thatCountry.name); } // now that we have the country, we create the airport Airport *newAirport = [NSEntityDescription insertNewObjectForEntityForName:@"Airport" inManagedObjectContext:managedObjectContext]; newAirport.city = [anAirport objectForKey:@"city"]; newAirport.code = [anAirport objectForKey:@"code"]; newAirport.name = [anAirport objectForKey:@"name"]; newAirport.country_name = [anAirport objectForKey:@"country_name"]; newAirport.latitude = [NSNumber numberWithDouble:[[anAirport objectForKey:@"latitude"] doubleValue]]; newAirport.longitude = [NSNumber numberWithDouble:[[anAirport objectForKey:@"longitude"] doubleValue]]; newAirport.altitude = [NSNumber numberWithDouble:[[anAirport objectForKey:@"altitude"] doubleValue]]; newAirport.country = thatCountry; // [thatCountry addAirportsObject:newAirport]; numAirports++; numUnsavedAirports++; if (numUnsavedAirports >= MAX_UNSAVED_AIRPORTS_BEFORE_SAVE) { if (![managedObjectContext save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } numUnsavedAirports = 0; } [pool release]; }

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  • SubSonic Stored Procedure Issue - Data Generated at Stored Procedure is different from Data Received

    - by ShaShaIn
    Hi All, I am facing a unknown problem while using stored procedure with SubSonic. I have written a stored procedure & application code that takes first name & last name as input parameter and return last login id as ouput parameter. It creates login id as first character of first name & complete last name for no-existing login id otherwise it adds 1 in the last login id e.g. First Name - Mark, Last Name - Waugh, First Login Id - MWaugh, Second Login Id - MWaugh1, Third Login Id - MWaugh2 etc. Stored Procedure SET ANSI_NULLS OFF GO SET QUOTED_IDENTIFIER ON GO CREATE PROCEDURE [dbo].[Users_FetchLoginId] ( @FirstName nvarchar(64), @LastName nvarchar(64), @LoginId nvarchar(256) OUTPUT ) AS DECLARE @UserId nvarchar(256); SET @UserId = NULL; SET @LoginId = NULL; SELECT @UserId = LoweredUserName FROM aspnet_Users WHERE LoweredUserName LIKE (LOWER(SUBSTRING(@FirstName,1,1) + @LastName)) IF @@rowcount = 0 OR @UserId IS NULL BEGIN SET @LoginId = (SUBSTRING(@FirstName, 1, 1) + @LastName); print @LoginId RETURN 1; END ELSE BEGIN SELECT TOP 1 LoweredUserName FROM aspnet_Users WHERE LoweredUserName LIKE (LOWER(SUBSTRING(@FirstName,1,1) + @LastName + '%')) ORDER BY LoweredUserName DESC RETURN 2; END Application Code public string FetchLoginId(string firstName, string lastName) { SubSonic.StoredProcedure sp = SPs.UsersFetchLoginId( firstName, lastName, null ); sp.Command.AddReturnParameter(); sp.Execute(); if (sp.Command.Parameters.Find(delegate(QueryParameter queryParameter) { return queryParameter.Mode == ParameterDirection.ReturnValue; }).ParameterValue != System.DBNull.Value) { int returnCode = Convert.ToInt32(sp.Command.Parameters.Find(delegate(QueryParameter queryParameter) { return queryParameter.Mode == ParameterDirection.ReturnValue; }).ParameterValue, CultureInfo.InvariantCulture); if (returnCode == 1) { // UserName as First Character of First Name & Full Last Name return sp.Command.Parameters[2].ParameterValue.ToString(); } if (returnCode == 2) { DataSet ds = sp.GetDataSet(); if (null == ds || null == ds.Tables[0] || 0 == ds.Tables[0].Rows.Count) return ""; string maxLoginId = ds.Tables[0].Rows[0]["LoweredUserName"].ToString(); string initialLoginId = firstName.Substring(0, 1) + lastName; int maxLoginIdIndex = 0; int initialLoginIdLength = initialLoginId.Length; if (maxLoginId.Substring(initialLoginIdLength).Length == 0) { maxLoginIdIndex++; // UserName as Max Lowered User Name Found & Incrementer as Suffix (Here, First Incrementer i.e. 1) return (initialLoginId + maxLoginIdIndex); } if (int.TryParse(maxLoginId.Substring(initialLoginIdLength), out maxLoginIdIndex)) { if (maxLoginIdIndex > 0) { maxLoginIdIndex++; // UserName as Max Lowered User Name Found & Incrementer as Suffix return (initialLoginId + maxLoginIdIndex); } } } } Now the problem is for some input (see test data below), the login id created at sql server end correctly but at application subsonic dal side, it truncates some characters. First Name - Jenelia and Last Name - Kanupatikenalaalayampentyalavelugoplansubhramanayam [dbo].[Users_FetchLoginId] - Execute Stored Procedure Separately - Login Id Is Correct JKanupatikenalaalayampentyalavelugoplansubhramanayam public string FetchLoginId(string firstName, string lastName) - Application Code DAL Side - LginId Is Wrongly Received From Stored Procedure JKanupatikenalaalayampentyalavelugoplansubhramanay You can easily see that 2 charactes are removed. If the data is correctly generated by stored procedure then why the characters are removed when data is received in output parameter of stored procedure? Is it due to any internal known or unknown bug of SubSonic? Your help is significant. Thanks in advance...

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  • Adding Core Data to existing iPhone project

    - by swalkner
    I'd like to add core data to an existing iPhone project, but I still get a lot of compile errors: NSManagedObjectContext undeclared Expected specifier-qualifier-list before 'NSManagedObjectModel' ... I already added the Core Data Framework to the target (right click on my project under "Targets", "Add" - "Existing Frameworks", "CoreData.framework"). My header-file: NSManagedObjectModel *managedObjectModel; NSManagedObjectContext *managedObjectContext; NSPersistentStoreCoordinator *persistentStoreCoordinator; [...] @property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel; @property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext; @property (nonatomic, retain, readonly) NSPersistentStoreCoordinator *persistentStoreCoordinator; What am I missing? Starting a new project is not an option... Thanks a lot! edit sorry, I do have those implementations... but it seems like the Library is missing... the implementation methods are full with compile error like "managedObjectContext undeclared", "NSPersistentStoreCoordinator undeclared", but also with "Expected ')' before NSManagedObjectContext" (although it seems like the parenthesis are correct)... #pragma mark - #pragma mark Core Data stack /** Returns the managed object context for the application. If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application. */ - (NSManagedObjectContext *) managedObjectContext { if (managedObjectContext != nil) { return managedObjectContext; } NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { managedObjectContext = [[NSManagedObjectContext alloc] init]; [managedObjectContext setPersistentStoreCoordinator: coordinator]; } return managedObjectContext; } /** Returns the managed object model for the application. If the model doesn't already exist, it is created by merging all of the models found in application bundle. */ - (NSManagedObjectModel *)managedObjectModel { if (managedObjectModel != nil) { return managedObjectModel; } managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain]; return managedObjectModel; } /** Returns the persistent store coordinator for the application. If the coordinator doesn't already exist, it is created and the application's store added to it. */ - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { if (persistentStoreCoordinator != nil) { return persistentStoreCoordinator; } NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Core_Data.sqlite"]]; NSError *error = nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&error]) { /* Replace this implementation with code to handle the error appropriately. abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button. Typical reasons for an error here include: * The persistent store is not accessible * The schema for the persistent store is incompatible with current managed object model Check the error message to determine what the actual problem was. */ NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } return persistentStoreCoordinator; }

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