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  • Return an opaque object to the caller without violating type-safety

    - by JS Bangs
    I have a method which should return a snapshot of the current state, and another method which restores that state. public class MachineModel { public Snapshot CurrentSnapshot { get; } public void RestoreSnapshot (Snapshot saved) { /* etc */ }; } The state Snapshot class should be completely opaque to the caller--no visible methods or properties--but its properties have to be visible within the MachineModel class. I could obviously do this by downcasting, i.e. have CurrentSnapshot return an object, and have RestoreSnapshot accept an object argument which it casts back to a Snapshot. But forced casting like that makes me feel dirty. What's the best alternate design that allows me to be both type-safe and opaque?

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  • which type is best for three radiobuttons?

    - by Manog
    Maybe you consider this question trivial but im just curious what is your opinion. I have three radiobuttons. "Show blue", "Show red" and "Show all". I did it with nullable boolean. There is collumn in database where blue is 0 and red is 1 so in metode i have to translate bool to int to compare those values (i do it in c#).Of course it works, but i wonder if it is the best solution. And question is wich type is best in this case? nullable bool, int, or maybe string?

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  • Switch Case on type of object (C#)

    - by Sem Dendoncker
    If you want to switch a type of object, what is the best way to do this? ex: private int GetNodeType(NodeDTO node) { switch (node.GetType()) { case typeof(CasusNodeDTO): return 1; case typeof(BucketNodeDTO): return 3; case typeof(BranchNodeDTO): return 0; case typeof(LeafNodeDTO): return 2; default: return -1; } } I know this doesn't work that way, but I was wondering how you could solve this. Is an if then else else else statement appropriate in this case? Or do you use this switch and add .ToString() to the types? Kind regards, Sem

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  • Implicit type conversion in DB/2 inserts?

    - by IronGoofy
    We're using SQL Inserts to insert some data via a script into DB/2 tables, e.g. CREATE TABLE TICKETS (TICKETID VARCHAR(10) NOT NULL); On my home installation, this statement works fine (note that I'm using an integer which is autoatically cast into a VarChar): INSERT INTO TICKETS (TICKETID) VALUES (1); while at my customer's site I get a type error. My question(s): Is this behavior version dependent? (I use a DB2 Express V9.7, while the customer has an Enterprise V9.5) Is there a config option to change the behavior? (I would like my home install to behave as close as possible as the production environment is going to be.)

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  • Is it possible to use XStream with an abstract node?

    - by Dan Watling
    My client application is making calls to a service that returns a common "root" XML, but a different result node. The "root" XML contains possible error codes. Is it possible to use XStream in this scenario? Example: public class RootNode { ErrorInfo errorInfo; BaseResult result; ... } public class ErrorInfo { String message; ... } public abstract BaseResult { } public class SearchResult extends BaseResult { List<Object> searchResults; ... } public class AccountResult extends BaseResult { String name; ... } The XML coming back could be one of two formats: <root> <errorInfo><message>...</message></errorInfo> <result> <searchResults>...</searchResults> </result> </root> OR <root> <errorInfo><message>...</message></errorInfo> <result> <name>...</name> </result> </root> I have set up my XStream object as follows: XStream x = new XStream(); x.alias("root", Root.class); x.alias("errorInfo", ErrorInfo.class); x.alias("result", <SearchResult.class OR AccountResult.class depending on what I am expecting back>); Of course, when I run this I receive an error telling me XStream cannot instantiate the base class (BaseResult). For fun, I also converted the BaseResult into an interface but received a similar error. I've looked through XStream's documentation and it isn't clear to me how to handle a situation like the one I just described. Is it even possible to do using XStream? Thanks, -Dan

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  • Big Data: Size isn’t everything

    - by Simon Elliston Ball
    Big Data has a big problem; it’s the word “Big”. These days, a quick Google search will uncover terabytes of negative opinion about the futility of relying on huge volumes of data to produce magical, meaningful insight. There are also many clichéd but correct assertions about the difficulties of correlation versus causation, in massive data sets. In reading some of these pieces, I begin to understand how climatologists must feel when people complain ironically about “global warming” during snowfall. Big Data has a name problem. There is a lot more to it than size. Shape, Speed, and…err…Veracity are also key elements (now I understand why Gartner and the gang went with V’s instead of S’s). The need to handle data of different shapes (Variety) is not new. Data developers have always had to mold strange-shaped data into our reporting systems, integrating with semi-structured sources, and even straying into full-text searching. However, what we lacked was an easy way to add semi-structured and unstructured data to our arsenal. New “Big Data” tools such as MongoDB, and other NoSQL (Not Only SQL) databases, or a graph database like Neo4J, fill this gap. Still, to many, they simply introduce noise to the clean signal that is their sensibly normalized data structures. What about speed (Velocity)? It’s not just high frequency trading that generates data faster than a single system can handle. Many other applications need to make trade-offs that traditional databases won’t, in order to cope with high data insert speeds, or to extract quickly the required information from data streams. Unfortunately, many people equate Big Data with the Hadoop platform, whose batch driven queries and job processing queues have little to do with “velocity”. StreamInsight, Esper and Tibco BusinessEvents are examples of Big Data tools designed to handle high-velocity data streams. Again, the name doesn’t do the discipline of Big Data any favors. Ultimately, though, does analyzing fast moving data produce insights as useful as the ones we get through a more considered approach, enabled by traditional BI? Finally, we have Veracity and Value. In many ways, these additions to the classic Volume, Velocity and Variety trio acknowledge the criticism that without high-quality data and genuinely valuable outputs then data, big or otherwise, is worthless. As a discipline, Big Data has recognized this, and data quality and cleaning tools are starting to appear to support it. Rather than simply decrying the irrelevance of Volume, we need as a profession to focus how to improve Veracity and Value. Perhaps we should just declare the ‘Big’ silent, embrace these new data tools and help develop better practices for their use, just as we did the good old RDBMS? What does Big Data mean to you? Which V gives your business the most pain, or the most value? Do you see these new tools as a useful addition to the BI toolbox, or are they just enabling a dangerous trend to find ghosts in the noise?

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  • SQL SERVER – MSQL_XP – Wait Type – Day 20 of 28

    - by pinaldave
    In this blog post, I am going to discuss something from my field experience. While consultation, I have seen various wait typed, but one of my customers who has been using SQL Server for all his operations had an interesting issue with a particular wait type. Our customer had more than 100+ SQL Server instances running and the whole server had MSSQL_XP wait type as the most number of wait types. While running sp_who2 and other diagnosis queries, I could not immediately figure out what the issue was because the query with that kind of wait type was nowhere to be found. After a day of research, I was relieved that the solution was very easy to figure out. Let us continue discussing this wait type. From Book On-Line: ?MSQL_XP occurs when a task is waiting for an extended stored procedure to end. SQL Server uses this wait state to detect potential MARS application deadlocks. The wait stops when the extended stored procedure call ends. MSQL_XP Explanation: This wait type is created because of the extended stored procedure. Extended Stored Procedures are executed within SQL Server; however, SQL Server has no control over them. Unless you know what the code for the extended stored procedure is and what it is doing, it is impossible to understand why this wait type is coming up. Reducing MSQL_XP wait: As discussed, it is hard to understand the Extended Stored Procedure if the code for it is not available. In the scenario described at the beginning of this post, our client was using third-party backup tool. The third-party backup tool was using Extended Stored Procedure. After we learned that this wait type was coming from the extended stored procedure of the backup tool they were using, we contacted the tech team of its vendor. The vendor admitted that the code was not optimal at some places, and within that day they had provided the patch. Once the updated version was installed, the issue on this wait type disappeared. As viewed in the wait statistics of all the 100+ SQL Server, there was no more MSSQL_XP wait type found. In simpler terms, you must first identify which Extended Stored Procedure is creating the wait type of MSSQL_XP and see if you can get in touch with the creator of the SP so you can help them optimize the code. If you have encountered this MSSQL_XP wait type, I encourage all of you to write how you managed it. Please do not mention the name of the vendor in your comment as I will not approve it. The focus of this blog post is to understand the wait types; not talk about others. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • Know your Data Lineage

    - by Simon Elliston Ball
    An academic paper without the footnotes isn’t an academic paper. Journalists wouldn’t base a news article on facts that they can’t verify. So why would anyone publish reports without being able to say where the data has come from and be confident of its quality, in other words, without knowing its lineage. (sometimes referred to as ‘provenance’ or ‘pedigree’) The number and variety of data sources, both traditional and new, increases inexorably. Data comes clean or dirty, processed or raw, unimpeachable or entirely fabricated. On its journey to our report, from its source, the data can travel through a network of interconnected pipes, passing through numerous distinct systems, each managed by different people. At each point along the pipeline, it can be changed, filtered, aggregated and combined. When the data finally emerges, how can we be sure that it is right? How can we be certain that no part of the data collection was based on incorrect assumptions, that key data points haven’t been left out, or that the sources are good? Even when we’re using data science to give us an approximate or probable answer, we cannot have any confidence in the results without confidence in the data from which it came. You need to know what has been done to your data, where it came from, and who is responsible for each stage of the analysis. This information represents your data lineage; it is your stack-trace. If you’re an analyst, suspicious of a number, it tells you why the number is there and how it got there. If you’re a developer, working on a pipeline, it provides the context you need to track down the bug. If you’re a manager, or an auditor, it lets you know the right things are being done. Lineage tracking is part of good data governance. Most audit and lineage systems require you to buy into their whole structure. If you are using Hadoop for your data storage and processing, then tools like Falcon allow you to track lineage, as long as you are using Falcon to write and run the pipeline. It can mean learning a new way of running your jobs (or using some sort of proxy), and even a distinct way of writing your queries. Other Hadoop tools provide a lot of operational and audit information, spread throughout the many logs produced by Hive, Sqoop, MapReduce and all the various moving parts that make up the eco-system. To get a full picture of what’s going on in your Hadoop system you need to capture both Falcon lineage and the data-exhaust of other tools that Falcon can’t orchestrate. However, the problem is bigger even that that. Often, Hadoop is just one piece in a larger processing workflow. The next step of the challenge is how you bind together the lineage metadata describing what happened before and after Hadoop, where ‘after’ could be  a data analysis environment like R, an application, or even directly into an end-user tool such as Tableau or Excel. One possibility is to push as much as you can of your key analytics into Hadoop, but would you give up the power, and familiarity of your existing tools in return for a reliable way of tracking lineage? Lineage and auditing should work consistently, automatically and quietly, allowing users to access their data with any tool they require to use. The real solution, therefore, is to create a consistent method by which to bring lineage data from these data various disparate sources into the data analysis platform that you use, rather than being forced to use the tool that manages the pipeline for the lineage and a different tool for the data analysis. The key is to keep your logs, keep your audit data, from every source, bring them together and use the data analysis tools to trace the paths from raw data to the answer that data analysis provides.

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  • Another BC30002: Type is not defined.

    - by brett
    Here's what I've done... I used wsdl.exe to create a .cs class for my wsdl service connection. I made a Visual Studio project to compile the .cs into a dll having namespace CalculatorService (CalculatorService.dll). Successful thus far. I created an asp.net project added my namespace import: %@ Import Namespace="CalculatorService" % I right-clicked on the project, clicked Add Reference, found my .dll, added it, built the project, checked /bin to ensure my dll was there (and it was). % 'I called the namespace:' Dim calcService As New CalculatorService.CalculatorService() 'called the function from the service' Dim xmlResult = calcService.GetSVS_ItemTable_XML("", "", "", "", "", "") 'printed the result' Response.Write(xmlResult) % All is well LOCALLY while debugging. It found the CalculatorService, connected to it, got the XML and displayed it. I then wanted to put it on the web so I built and published my project: under "Copy" - Only files needed to run this application...selected! Deploying on the web says Type 'CalculatorService.CalculatorService' is not defined. Here is a link to the live script: http://vansmith.com/_iaps.wsdl/pub/Default.aspx Any ideas?

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  • How to create this MongoMapper custom data type?

    - by Kapslok
    I'm trying to create a custom MongoMapper data type in RoR 2.3.5 called Translatable: class Translatable < String def initialize(translation, culture="en") end def languages end def has_translation(culture)? end def self.to_mongo(value) end def self.from_mongo(value) end end I want to be able to use it like this: class Page include MongoMapper::Document key :title, Translatable, :required => true key :content, String end Then implement like this: p = Page.new p.title = "Hello" p.title(:fr) = "Bonjour" p.title(:es) = "Hola" p.content = "Some content here" p.save p = Page.first p.languages => [:en, :fr, :es] p.has_translation(:fr) => true en = p.title => "Hello" en = p.title(:en) => "Hello" fr = p.title(:fr) => "Bonjour" es = p.title(:es) => "Hola" In mongoDB I imagine the information would be stored like: { "_id" : ObjectId("4b98cd7803bca46ca6000002"), "title" : { "en" : "Hello", "fr" : "Bonjour", "es" : "Hola" }, "content" : "Some content here" } So Page.title is a string that defaults to English (:en) when culture is not specified. I would really appreciate any help.

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  • Extending the .NET type system so the compiler enforces semantic meaning of primitive values in cert

    - by Drew Noakes
    I'm working with geometry a bit at the moment and am converting a lot between degrees and radians. Unfortunately, both of these are represented by double, so there's compile time warning/error if I try to pass a value in degrees where radians are expected. I believe F# has a compile-time solution for this (called units of measure.) I'd like to do something similar in C#. As another example, imagine a SQL library that accepts various query parameters as strings. It'd be good to have a way of enforcing that only clean strings were allowed to be passed in at runtime, and the only way to get a clean string was to pass through some SQL injection attack preventing logic. The obvious solution is to wrap the double/string/whatever in a new type to give it the type information the compiler needs. I'm curious if anyone has an alternative solution. If you do think wrapping is the only/best way, then please go into some of the downsides of the pattern (and any upsides I haven't mentioned too.) I'm especially concerned about the performance of abstracted primitive numeric types on my calculations at runtime.

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  • NSURLConnection receives data even if no data was thrown back

    - by Anna Fortuna
    Let me explain my situation. Currently, I am experimenting long-polling using NSURLConnection. I found this and I decided to try it. What I do is send a request to the server with a timeout interval of 300 secs. (or 5 mins.) Here is a code snippet: NSURL *url = [NSURL URLWithString:urlString]; NSURLRequest *request = [NSURLRequest requestWithURL:url cachePolicy:NSURLCacheStorageAllowedInMemoryOnly timeoutInterval:300]; NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&resp error:&err]; Now I want to test if the connection will "hold" the request if no data was thrown back from the server, so what I did was this: if (data != nil) [self performSelectorOnMainThread:@selector(dataReceived:) withObject:data waitUntilDone:YES]; And the function dataReceived: looks like this: - (void)dataReceived:(NSData *)data { NSLog(@"DATA RECEIVED!"); NSString *string = [NSString stringWithUTF8String:[data bytes]]; NSLog(@"THE DATA: %@", string); } Server-side, I created a function that will return a data once it fits the arguments and returns none if nothing fits. Here is a snippet of the PHP function: function retrieveMessages($vardata) { if (!empty($vardata)) { $result = check_data($vardata) //check_data is the function which returns 1 if $vardata //fits the arguments, and 0 if it fails to fit if ($result == 1) { $jsonArray = array('Data' => $vardata); echo json_encode($jsonArray); } } } As you can see, the function will only return data if the $result is equal to 1. However, even if the function returns nothing, NSURLConnection will still perform the function dataReceived: meaning the NSURLConnection still receives data, albeit an empty one. So can anyone help me here? How will I perform long-polling using NSURLConnection? Basically, I want to maintain the connection as long as no data is returned. So how will I do it? NOTE: I am new to PHP, so if my code is wrong, please point it out so I can correct it.

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  • How to maintain an ordered table with Core Data (or SQL) with insertions/deletions?

    - by Jean-Denis Muys
    This question is in the context of Core Data, but if I am not mistaken, it applies equally well to a more general SQL case. I want to maintain an ordered table using Core Data, with the possibility for the user to: reorder rows insert new lines anywhere delete any existing line What's the best data model to do that? I can see two ways: 1) Model it as an array: I add an int position property to my entity 2) Model it as a linked list: I add two one-to-one relations, next and previous from my entity to itself 1) makes it easy to sort, but painful to insert or delete as you then have to update the position of all objects that come after 2) makes it easy to insert or delete, but very difficult to sort. In fact, I don't think I know how to express a Sort Descriptor (SQL ORDER BY clause) for that case. Now I can imagine a variation on 1): 3) add an int ordering property to the entity, but instead of having it count one-by-one, have it count 100 by 100 (for example). Then inserting is as simple as finding any number between the ordering of the previous and next existing objects. The expensive renumbering only has to occur when the 100 holes have been filled. Making that property a float rather than an int makes it even better: it's almost always possible to find a new float midway between two floats. Am I on the right track with solution 3), or is there something smarter?

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  • Weird compile-time behavior when trying to use primitive type in generics

    - by polygenelubricants
    import java.lang.reflect.Array; public class PrimitiveArrayGeneric { static <T> T[] genericArrayNewInstance(Class<T> componentType) { return (T[]) Array.newInstance(componentType, 0); } public static void main(String args[]) { int[] intArray; Integer[] integerArray; intArray = (int[]) Array.newInstance(int.class, 0); // Okay! integerArray = genericArrayNewInstance(Integer.class); // Okay! intArray = genericArrayNewInstance(int.class); // Compile time error: // cannot convert from Integer[] to int[] integerArray = genericArrayNewInstance(int.class); // Run time error: // ClassCastException: [I cannot be cast to [Ljava.lang.Object; } } I'm trying to fully understand how generics works in Java. Things get a bit weird for me in the 3rd assignment in the above snippet: the compiler is complaining that Integer[] cannot be converted to int[]. The statement is 100% true, of course, but I'm wondering WHY the compiler is making this complaint. If you comment that line, and follow the compiler's "suggestion" as in the 4th assignment, the compiler is actually satisfied!!! NOW the code compiles just fine! Which is crazy, of course, since like the run time behavior suggests, int[] cannot be converted to Object[] (which is what T[] is type-erased into at run time). So my question is: why is the compiler "suggesting" that I assign to Integer[] instead for the 3rd assignment? How does the compiler reason to arrive to that (erroneous!) conclusion?

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  • Argument type deduction, references and rvalues

    - by uj2
    Consider the situation where a function template needs to forward an argument while keeping it's lvalue-ness in case it's a non-const lvalue, but is itself agnostic to what the argument actually is, as in: template <typename T> void target(T&) { cout << "non-const lvalue"; } template <typename T> void target(const T&) { cout << "const lvalue or rvalue"; } template <typename T> void forward(T& x) { target(x); } When x is an rvalue, instead of T being deduced to a constant type, it gives an error: int x = 0; const int y = 0; forward(x); // T = int forward(y); // T = const int forward(0); // Hopefully, T = const int, but actually an error forward<const int>(0); // Works, T = const int It seems that for forward to handle rvalues (without calling for explicit template arguments) there needs to be an forward(const T&) overload, even though it's body would be an exact duplicate. Is there any way to avoid this duplication?

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  • How can I scrape specific data from a website

    - by Stoney
    I'm trying to scrape data from a website for research. The urls are nicely organized in an example.com/x format, with x as an ascending number and all of the pages are structured in the same way. I just need to grab certain headings and a few numbers which are always in the same locations. I'll then need to get this data into structured form for analysis in Excel. I have used wget before to download pages, but I can't figure out how to grab specific lines of text. Excel has a feature to grab data from the web (Data-From Web) but from what I can see it only allows me to download tables. Unfortunately, the data I need is not in tables.

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  • How should I architect my Model and Data Access layer objects in my website?

    - by Robin Winslow
    I've been tasked with designing Data layer for a website at work, and I am very interested in architecture of code for the best flexibility, maintainability and readability. I am generally acutely aware of the value in completely separating out my actual Models from the Data Access layer, so that the Models are completely naive when it comes to Data Access. And in this case it's particularly useful to do this as the Models may be built from the Database or may be built from a Soap web service. So it seems to me to make sense to have Factories in my data access layer which create Model objects. So here's what I have so far (in my made-up pseudocode): class DataAccess.ProductsFromXml extends DataAccess.ProductFactory {} class DataAccess.ProductsFromDatabase extends DataAccess.ProductFactory {} These then get used in the controller in a fashion similar to the following: var xmlProductCreator = DataAccess.ProductsFromXml(xmlDataProvider); var databaseProductCreator = DataAccess.ProductsFromXml(xmlDataProvider); // Returns array of Product model objects var XmlProducts = databaseProductCreator.Products(); // Returns array of Product model objects var DbProducts = xmlProductCreator.Products(); So my question is, is this a good structure for my Data Access layer? Is it a good idea to use a Factory for building my Model objects from the data? Do you think I've misunderstood something? And are there any general patterns I should read up on for how to write my data access objects to create my Model objects?

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  • How are the conceptual pairs Abstract/Concrete, Generic/Specific, and Complex/Simple related to one another in software architecture?

    - by tjb1982
    (= 2 (+ 1 1)) take the above. The requirement of the '=' predicate is that its arguments be comparable. Any two structures are comparable in this case, and so the contract/requirement is pretty generic. The '+' predicate requires that its arguments be numbers. That's more specific. (socket domain type protocol) the arguments here are much more specific (even though the arguments are still just numbers and the function itself returns a file descriptor, which is itself an int), but the arguments are more abstract, and the implementation is built up from other functions whose abstractions are less abstract, which are themselves built from less and less abstract abstractions. To the point where the requirements are something like move from one location to another, observe whether the switch at that location is on or off, turn the switch on or off, or leave it the same, etc. But are functions also less and less complex the less abstract they are? And is there a relationship between the number and range of arguments of a function and the complexity of its implementation, as you go from more abstract to less abstract, and vice versa? (= 2 (+ 1 1) 2r10) the '=' predicate is more generic than the '+' predicate, and thus could be more complex in its implementation. The '+' predicate's contract is less generic, and so could be less complex in its implementation. Is this even a little correct? What about the 'socket' function? Each of those arguments is a number of some kind. What they represent, though, is something more elaborate. It also returns a number (just like the others do), which is also a representation of something conceptually much more elaborate than a number. To boil it down, I'm asking if there is a relationship between the following dimensions, and why: Abstract/Concrete Complex/Simple Generic/Specific And more specifically, do different configurations of these dimensions have a specific, measurable impact on the number and range of the arguments (i.e., the contract) of a function?

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  • Java Builder pattern with Generic type bounds

    - by I82Much
    Hi all, I'm attempting to create a class with many parameters, using a Builder pattern rather than telescoping constructors. I'm doing this in the way described by Joshua Bloch's Effective Java, having private constructor on the enclosing class, and a public static Builder class. The Builder class ensures the object is in a consistent state before calling build(), at which point it delegates the construction of the enclosing object to the private constructor. Thus public class Foo { // Many variables private Foo(Builder b) { // Use all of b's variables to initialize self } public static final class Builder { public Builder(/* required variables */) { } public Builder var1(Var var) { // set it return this; } public Foo build() { return new Foo(this); } } } I then want to add type bounds to some of the variables, and thus need to parametrize the class definition. I want the bounds of the Foo class to be the same as that of the Builder class. public class Foo<Q extends Quantity> { private final Unit<Q> units; // Many variables private Foo(Builder<Q> b) { // Use all of b's variables to initialize self } public static final class Builder<Q extends Quantity> { private Unit<Q> units; public Builder(/* required variables */) { } public Builder units(Unit<Q> units) { this.units = units; return this; } public Foo build() { return new Foo<Q>(this); } } } This compiles fine, but the compiler is allowing me to do things I feel should be compiler errors. E.g. public static final Foo.Builder<Acceleration> x_Body_AccelField = new Foo.Builder<Acceleration>() .units(SI.METER) .build(); Here the units argument is not Unit<Acceleration> but Unit<Length>, but it is still accepted by the compiler. What am I doing wrong here? I want to ensure at compile time that the unit types match up correctly.

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  • Core data migration failing with "Can't find model for source store" but managedObjectModel for source is present

    - by Ira Cooke
    I have a cocoa application using core-data, which is now at the 4th version of its managed object model. My managed object model contains abstract entities but so far I have managed to get migration working by creating appropriate mapping models and creating my persistent store using addPersistentStoreWithType:configuration:options:error and with the NSMigratePersistentStoresAutomaticallyOption set to YES. NSDictionary *optionsDictionary = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:NSMigratePersistentStoresAutomaticallyOption]; NSURL *url = [NSURL fileURLWithPath: [applicationSupportFolder stringByAppendingPathComponent: @"MyApp.xml"]]; NSError *error=nil; [theCoordinator addPersistentStoreWithType:NSXMLStoreType configuration:nil URL:url options:optionsDictionary error:&error] This works fine when I migrate from model version 3 to 4, which is a migration that involves adding attributes to several entities. Now when I try to add a new model version (version 5), the call to addPersistentStoreWithType returns nil and the error remains empty. The migration from 4 to 5 involves adding a single attribute. I am struggling to debug the problem and have checked all the following; The source database is in fact at version 4 and the persistentStoreCoordinator's managed object model is at version 5. The 4-5 mapping model as well as managed object models for versions 4 and 5 are present in the resources folder of my built application. I've tried various model upgrade paths. Strangely I find that upgrading from an early version 3 - 5 works .. but upgrading from 4 - 5 fails. I've tried adding a custom entity migration policy for migration of the entity whose attributes are changing ... in this case I overrode the method beginEntityMapping:manager:error: . Interestingly this method does get called when migration works (ie when I migrate from 3 to 4, or from 3 to 5 ), but it does not get called in the case that fails ( 4 to 5 ). I'm pretty much at a loss as to where to proceed. Any ideas to help debug this problem would be much appreciated.

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  • drop down and post data to data base

    - by DAFFODIL
    This is a form which retrieves data from db and displays them in table. At the beginning of each row there will be a check box. If there are 10 rows fetched, I ii check 5 rows and insert them in to diff db but here when, I click drop down box data is getting in to db automatically,bcoz I use onchange event. Any alternative to prevent this to happen. Data should be inserted only when, I click submit button. Any help will be appreciated <?php $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("form1", $con); error_reporting(E_ALL ^ E_NOTICE); $nam=$_REQUEST['select1']; $row=mysql_query("select * from inv where name='$nam'"); while($row1=mysql_fetch_array($row)) { $Name=$row1['Name']; $Address =$row1['Address']; $City=$row1['City']; $Pincode=$row1['Pincode']; $No=$row1['No']; $Date=$row1['Date']; $DCNo=$row1['DCNo']; $DcDate=$row1['DcDate']; $YourOrderNo=$row1['YourOrderNo']; $OrderDate=$row1['OrderDate']; $VendorCode=$row1['VendorCode']; $SNo=$row1['SNo']; $descofgoods=$row1['descofgoods']; $Qty=$row1['Qty']; $Rate=$row1['Rate']; $Amount=$row1['Amount']; } ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Untitled Document</title> <script type="text/javascript"> function ram(id) { var q=document.getElementById('qty_'+id).value; var r=document.getElementById('rate_'+id).value; document.getElementById('amt_'+id).value=q*r; } </script> </head> <body> <form id="form1" name="form1" method="post" action=""> <table width="1315" border="0"> <script type="text/javascript"> function g() { form1.submit(); } </script> <tr> <th>Name</th> <th align="left"><select name="select1" onchange="g();"> <option value="" selected="selected">select</option> <?php $row=mysql_query("select Name from inv "); while($row1=mysql_fetch_array($row)) { ?> <option value="<?php echo $row1['Name'];?>"><?php echo $row1['Name'];?></option> <?php } ?> </select></th> </tr> <tr> <th>Address</th> <th align="left"><textarea name="Address"><?php echo $Address;?></textarea></th> </tr> <tr> <th>City</th> <th align="left"><input type="text" name="City" value='<?php echo $City;?>' /></th> </tr> <tr> <th>Pincode</th> <th align="left"><input type="text" name="Pincode" value='<?php echo $Pincode;?>'></th> </tr> <tr> <th>No</th> <th align="left"><input type="text" name="No2" value='<?php echo $No;?>' readonly="" /></th> </tr> <tr> <th>Date</th> <th align="left"><input type="text" name="Date" value='<?php echo $Date;?>' /></th> </tr> <tr> <th>DCNo</th> <th align="left"><input type="text" name="DCNo" value='<?php echo $DCNo;?>' readonly="" /></th> </tr> <tr> <th>DcDate:</th> <th align="left"><input type="text" name="DcDate" value='<?php echo $DcDate;?>' /></th> </tr> <tr> <th>YourOrderNo</th> <th align="left"><input type="text" name="YourOrderNo" value='<?php echo $YourOrderNo;?>' readonly="" /></th> </tr> <tr> <th>OrderDate</th> <th align="left"><input type="text" name="OrderDate" value='<?php echo $OrderDate;?>' /></th> </tr> <tr> <th width="80">VendorCode</th> <th width="1225" align="left"><input type="text" name="VendorCode" value='<?php echo $VendorCode;?>' readonly="" /></th> </tr> </table> <table width="1313" border="0"> <tr> <td width="44">&nbsp;</td> <td width="71">SNO</td> <td width="527">DESCRIPTION</td> <td width="214">QUANTITY</td> <td width="214">RATE/UNIT</td> <td width="217">AMOUNT</td> </tr> <?php $i=1; $row=mysql_query("select * from inv where Name='$nam'"); while($row1=mysql_fetch_array($row)) { $SNo=$row1['SNo']; $descofgoods=$row1['descofgoods']; $Qty=$row1['Qty']; $Rate=$row1['Rate']; $Amount=$row1['Amount']; ?> <tr> <td><input type="checkbox" name="checkbox" value="checkbox" checked="checked"/></td> <td><input type="text" name="No[<?php echo $i?>]" value='<?php echo $SNo;?>' readonly=""/></td> <td><input type="text" name="descofgoods[<?php echo $i?>]" value='<?php echo $descofgoods;?>' /></td> <td><input type="text" name="qty[<?php echo $i?>]" maxlength="50000000" id="qty_<?PHP echo($i) ?>"/></td> <td><input type="text" name="Rate[<?php echo $i?>]" value='<?php echo $Rate;?>' id="rate_<?PHP echo($i) ?>" onclick="ram('<?PHP echo($i) ?>')";></td> <td><input type="text" name="Amount[<?php echo $i?>]" id="amt_<?PHP echo($i) ?>"/></td> </tr> <?php $i++;} ?> <tr> <td><input type="submit" value="submit" header("location:values to be brought for print page.php");/></td> </tr> </table> <label></label> </form> </body> </html> <?php /*error_reporting(E_ALL ^ E_NOTICE); $con = mysql_connect("localhost","root",""); if (!$con) { die('Could not connect: ' . mysql_error()); } mysql_select_db("form1", $con); /*if(checked=checkbox) { mysql_query="INSERT INTO invo (Name, Address, City, Pincode, No, Date, DCNo, DcDate, YourOrderNo, OrderDate, VendorCode, SNo, descofgoods, Qty, Rate, Amount) VALUES ('$_POST[Name]','$_POST[Address]','$_POST[City]','$_POST[Pincode]','$_POST[No]','$_POST[Date]','$_POST[DCNo]','$_POST[DcDate]','$_POST[YourOrderNo]','$_POST[OrderDate]','$_POST[VendorCode]','$_POST[SNo]','$_POST[descofgoods]','$_POST[qty]','$_POST[Rate]','$_POST[Amount]')"; } else { header("location:values to be brought for print page.php"); }*/ header("ins.php"); ?>

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  • Choosing a type for search results in C#

    - by Chris M
    I have a result set that will never exceed 500; the results that come back from the web-service are assigned to a search results object. The data from the webservice is about 2mb; the bit I want to use is about a third of each record, so this allows me to cache and quickly manipulate it. I want to be able to sort and filter the results with the least amount of overhead and as fast as possible so I used the VCSKICKS timing class to measure their performance Average Total (10,000) Type Create Sort Create Sort HashSet 0.1579 0.0003 1579 3 IList 0.0633 0.0002 633 2 IQueryable 0.0072 0.0432 72 432 Measured in Seconds using http://www.vcskicks.com/algorithm-performance.php I created the hashset through a for loop over the web-service response (adding to the hashset). The List & IQueryable were created using LINQ. Question I can understand why HashSet takes longer to create (the foreach loop vs linq); but why would IQueryable take longer to sort than the other two; and finally is there a better way to assign the HashSet. Thanks Actual Program public class Program { private static AuthenticationHeader _authHeader; private static OPSoapClient _opSession; private static AccommodationSearchResponse _searchResults; private static HashSet<SearchResults> _myHash; private static IList<SearchResults> _myList; private static IQueryable<SearchResults> _myIQuery; static void Main(string[] args) { #region Setup WebService _authHeader = new AuthenticationHeader { UserName = "xx", Password = "xx" }; _opSession = new OPSoapClient(); #region Setup Search Results _searchResults = _opgSession.SearchCR(_authHeader, "ENG", "GBP", "GBR"); #endregion Setup Search Results #endregion Setup WebService // HASHSET SpeedTester hashTest = new SpeedTester(TestHashSet); hashTest.RunTest(); Console.WriteLine("- Hash Test \nAverage Running Time: {0}; Total Time: {1}", hashTest.AverageRunningTime, hashTest.TotalRunningTime); SpeedTester hashSortTest = new SpeedTester(TestSortingHashSet); hashSortTest.RunTest(); Console.WriteLine("- Hash Sort Test \nAverage Running Time: {0}; Total Time: {1}", hashSortTest.AverageRunningTime, hashSortTest.TotalRunningTime); // ILIST SpeedTester listTest = new SpeedTester(TestList); listTest.RunTest(); Console.WriteLine("- List Test \nAverage Running Time: {0}; Total Time: {1}", listTest.AverageRunningTime, listTest.TotalRunningTime); SpeedTester listSortTest = new SpeedTester(TestSortingList); listSortTest.RunTest(); Console.WriteLine("- List Sort Test \nAverage Running Time: {0}; Total Time: {1}", listSortTest.AverageRunningTime, listSortTest.TotalRunningTime); // IQUERIABLE SpeedTester iqueryTest = new SpeedTester(TestIQueriable); iqueryTest.RunTest(); Console.WriteLine("- iquery Test \nAverage Running Time: {0}; Total Time: {1}", iqueryTest.AverageRunningTime, iqueryTest.TotalRunningTime); SpeedTester iquerySortTest = new SpeedTester(TestSortableIQueriable); iquerySortTest.RunTest(); Console.WriteLine("- iquery Sort Test \nAverage Running Time: {0}; Total Time: {1}", iquerySortTest.AverageRunningTime, iquerySortTest.TotalRunningTime); } static void TestHashSet() { var test = _searchResults.Items; _myHash = new HashSet<SearchResults>(); foreach(var x in test) { _myHash.Add(new SearchResults { Ref = x.Ref, Price = x.StandardPrice }); } } static void TestSortingHashSet() { var sorted = _myHash.OrderBy(s => s.Price); } static void TestList() { var test = _searchResults.Items; _myList = (from x in test select new SearchResults { Ref = x.Ref, Price = x.StandardPrice }).ToList(); } static void TestSortingList() { var sorted = _myList.OrderBy(s => s.Price); } static void TestIQueriable() { var test = _searchResults.Items; _myIQuery = (from x in test select new SearchResults { Ref = x.Ref, Price = x.StandardPrice }).AsQueryable(); } static void TestSortableIQueriable() { var sorted = _myIQuery.OrderBy(s => s.Price); } }

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  • How can I split abstract testcases in JUnit?

    - by Willi Schönborn
    I have an abstract testcase "AbstractATest" for an interface "A". It has several test methods (@Test) and one abstract method: protected abstract A unit(); which provides the unit under testing. No i have multiple implementations of "A", e.g. "DefaultA", "ConcurrentA", etc. My problem: The testcase is huge (~1500 loc) and it's growing. So i wanted to split it into multiple testcases. How can organize/structure this in Junit 4 without the need to have a concrete testcase for every implementation and abstract testcase. I want e.g. "AInitializeTest", "AExectueTest" and "AStopTest". Each being abstract and containing multiple tests. But for my concrete "ConcurrentA", i only want to have one concrete testcase "ConcurrentATest". I hope my "problem" is clear. EDIT Looks like my description was not that clear. Is it possible to pass a reference to a test? I know parameterized tests, but these require static methods, which is not applicable to my setup. Subclasses of an abstract testcase decide about the parameter.

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  • Abstract Design Pattern implementation

    - by Pathachiever11
    I started learning design patterns a while ago (only covered facade and abstract so far, but am enjoying it). I'm looking to apply the Abstract pattern to a problem I have. The problem is: Supporting various Database systems using one abstract class and a set of methods and properties, which then the underlying concrete classes (inheriting from abstract class) would be implementing. I have created a DatabaseWrapper abstract class and have create SqlClientData and MSAccessData concrete class that inherit from the DatabaseWrapper. However, I'm still a bit confused about how the pattern goes as far as implementing these classes on the Client. Would I do the following?: DatabaseWrapper sqlClient = new SqlClientData(connectionString); This is what I saw in an example, but that is not what I'm looking for because I want to encapsulate the concrete classes; I only want the Client to use the abstract class. This is so I can support for more database systems in the future with minimal changes to the Client, and creating a new concrete class for the implementations. I'm still learning, so there might be a lot of things wrong here. Please tell me how I can encapsulate all the concrete classes, and if there is anything wrong with my approach. Many Thanks! PS: I'm very excited to get into software architecture, but still am a beginner, so take it easy on me. :)

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  • Using antlr and the DLR together -- AST conversion

    - by RCIX
    I have an AST generated via ANTLR, and I need to convert it to a DLR-compatible one (Expression Trees). However, it would seem that i can't use tree pattern matchers for this as expression trees need their subtrees at instantiation (which i can't get). What solution would be best for me to use?

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