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  • What are the "Navigation Properties" in this data model for?

    - by d03boy
    I've been wondering how to properly set up many-to-many relationships in ASP.NET MVC 2 using Linq2Sql for quite some time now. I found this blog post that seems to have a similar model layout as mine. If you take a look at the first screenshot showing the data model you can see that each model has "Navigation Properties" at the bottom of it. What exactly is this and why don't my models have them? I have the proper foreign keys put in to place. Most specifically, I am looking at the relationship between the Article and Category models since that is the only many-to-many relationship that I see and that's what I'm trying to model. Obviously I use an intermediary joining table between these two tables but I am having trouble understanding the proper methodology for modeling that relationship and I'm not finding this information anywhere on The Google.

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  • loading data from file into 2d array

    - by Chris
    I am just starting with perl and would like some help with arrays please. I am reading lines from a data file and splitting the line into fields: open (INFILE, $infile); do { my $linedata = <INFILE>; my @data= split ',',$linedata; .... } until eof; I then want to store the individual field values (in @data) in and array so that the array looks like the input data file ie, the first "row" of the array contains the first line of data from INFILE etc. Each line of data from the infile contains 4 values, x,y,z and w and once the data are all in the array, I have to pass the array into another program which reads the x,y,z,w and displays the w value on a screen at the point determined by the x,y,z value. I can not pas the data to the other program on a row-by-row basis as the program expects the data to in a 2d matrtix format. Any help greatly appreciated. Chris

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  • How to retrieve JSON Data Array from ExtJS Store

    - by user291928
    Is there a method allowing me to return my stored data in an ExtJS Grid Panel exactly the way I loaded it using: var data = ["value1", "value2"] Store.loadData(data); I would like to have a user option to reload the Grid, but changes to the store need to be taken into account. The user can make changes and the grid is dynamically updated, but if I reload the grid, the data that was originally loaded is shown even though the database has been updated with the new changes. I would prefer not to reload the page and just let them reload the grid data itself with the newly changed store. I guess im looking for something like this: var data = Store.getData(); //data = ["value1", "value2"] after its all said and done. Or is there a different way to refresh the grid with new data that I am not aware of. Even using the proxy still uses the "original" data, not the new store. Thanks in advance

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  • Best way to store a large amount of game objects and update the ones onscreen

    - by user3002473
    Good afternoon guys! I'm a young beginner game developer working on my first large scale game project and I've run into a situation where I'm not quite sure what the best solution may be (if there is a lone solution). The question may be vague (if anyone can think of a better title after having read the question, please edit it) or broad but I'm not quite sure what to do and I thought it would help just to discuss the problem with people more educated in the field. Before we get started, here are some of the questions I've looked at for help in the past: Best way to keep track of game objects Elegant way to simulate large amounts of entities within a game world What is the most efficient container to store dynamic game objects in? I've also read articles about different data structures commonly used in games to store game objects such as this one about slot maps, but none of them are really what I'm looking for. Also, if it helps at all I'm using Python 3 to design the game. It has to be Python 3, if I could I would use C++ or Unityscript or something else, but I'm restricted to having to use Python 3. My game will be a form of side scroller shooter game. In said game the player will traverse large rooms with large amounts of enemies and other game objects to update (think some of the larger areas in Cave Story or Iji). The player obviously can't see the entire room all at once, so there is a viewport that follows the player around and renders only a selection of the room and the game objects that it contains. This is not a foreign concept. The part that's getting me confused has to do with how certain game objects are updated. Some of them are to be updated constantly, regardless of whether or not they can be seen. Other objects however are only to be updated when they are onscreen (for example, an enemy would only be updated to react to the player when it is onscreen or when it is in a certain range of the screen). Another problem is that game objects have to be easily referable by other game objects; something that happens in the player's update() method may affect another object in the world. Collision detection in games is always a serious problem. I need a way of containing the game objects such that it minimizes the number of cases when testing for collisions against one another. The final problem is that of creating and destroying game objects. I think this problem is pretty self explanatory. To store the game objects then I've considered a number of different methods. The original method I had was to simply store all the objects in a hash table by an id. This method was simple, and decently fast as it allows all the objects to be looked up in O(1) complexity, and also allows them to be deleted fairly easily. Hash collisions would not be a major problem; I wasn't originally planning on using computer generated ids to store the game objects I was going to rely on them all using ids given to them by the game designer (such names would be strings like 'Player' or 'EnemyWeapon4'), and even if I did use computer generated ids, if I used a decent hashing algorithm then the chances of collisions would be around 1 in 4 billion. The problem with using a hash table however is that it is inefficient in checking to see what objects are in range of the viewport. Considering the fact that certain game objects move (as well as the viewport itself), the only solution I could think of in order to only update objects that are in the viewport would be to iterate through every object in the hash table and check if it is in the viewport or not, updating only the ones that are in the valid area. This would be incredibly slow in scenarios where the amount of game objects exceeds 500, or even 200. The second solution was to store everything in a 2-d list. The world is partitioned up into cells (a tilemap essentially), where each cell or tile is the same size and is square. Each cell would contain a list of the game objects that are currently occupying it (each game object would be inserted into a cell depending on the center of the object's collision mask). A 2-d list would allow me to take the top-left and bottom-right corners of the viewport and easily grab a rectangular area of the grid containing only the cells containing entities that are in valid range to be updated. This method also solves the problem of collision detection; when I take an entity I can find the cell that it is currently in, then check only against entities in it's cell and the 8 cells around it. One problem with this system however is that it prohibits easy lookup of game objects. One solution I had would be to simultaneously keep a hash table that would contain all the positions of the objects in the 2-d list indexed by the id of said object. The major problem with a 2-d list is that it would need to be rebuilt every single game frame (along with the hash table of object positions), which may be a serious detriment to game speed. Both systems have ups and downs and seem to solve some of each other's problems, however using them both together doesn't seem like the best solution either. If anyone has any thoughts, ideas, suggestions, comments, opinions or solutions on new data structures or better implementations of the existing data structures I have in mind, please post, any and all criticism and help is welcome. Thanks in advance! EDIT: Please don't close the question because it has a bad title, I'm just bad with names!

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  • Logging errors caused by exceptions deep in the application

    - by Kaleb Pederson
    What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error? For example, let's say that I have an ETL system whose transform step involves: a transformer, pipeline, processing algorithm, and processing engine. In brief, the transformer takes in an input file, parses out records, and sends the records through the pipeline. The pipeline aggregates the results of the processing algorithm (which could do serial or parallel processing). The processing algorithm sends each record through one or more processing engines. So, I have at least four levels: Transformer - Pipeline - Algorithm - Engine. My code might then look something like the following: class Transformer { void Process(InputSource input) { try { var inRecords = _parser.Parse(input.Stream); var outRecords = _pipeline.Transform(inRecords); } catch (Exception ex) { var inner = new ProcessException(input, ex); _logger.Error("Unable to parse source " + input.Name, inner); throw inner; } } } class Pipeline { IEnumerable<Result> Transform(IEnumerable<Record> records) { // NOTE: no try/catch as I have no useful information to provide // at this point in the process var results = _algorithm.Process(records); // examine and do useful things with results return results; } } class Algorithm { IEnumerable<Result> Process(IEnumerable<Record> records) { var results = new List<Result>(); foreach (var engine in Engines) { foreach (var record in records) { try { engine.Process(record); } catch (Exception ex) { var inner = new EngineProcessingException(engine, record, ex); _logger.Error("Engine {0} unable to parse record {1}", engine, record); throw inner; } } } } } class Engine { Result Process(Record record) { for (int i=0; i<record.SubRecords.Count; ++i) { try { Validate(record.subRecords[i]); } catch (Exception ex) { var inner = new RecordValidationException(record, i, ex); _logger.Error( "Validation of subrecord {0} failed for record {1}", i, record ); } } } } There's a few important things to notice: A single error at the deepest level causes three log entries (ugly? DOS?) Thrown exceptions contain all important and useful information Logging only happens when failure to do so would cause loss of useful information at a lower level. Thoughts and concerns: I don't like having so many log entries for each error I don't want to lose important, useful data; the exceptions contain all the important but the stacktrace is typically the only thing displayed besides the message. I can log at different levels (e.g., warning, informational) The higher level classes should be completely unaware of the structure of the lower-level exceptions (which may change as the different implementations are replaced). The information available at higher levels should not be passed to the lower levels. So, to restate the main questions: What are best-practices for logging deep within an application's source? Is it bad practice to have multiple event log entries for a single error?

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  • how to format date when i load data from google-app-engine..

    - by zjm1126
    i use remote_api to load data from google-app-engine. appcfg.py download_data --config_file=helloworld/GreetingLoad.py --filename=a.csv --kind=Greeting helloworld the setting is: class AlbumExporter(bulkloader.Exporter): def __init__(self): bulkloader.Exporter.__init__(self, 'Greeting', [('author', str, None), ('content', str, None), ('date', str, None), ]) exporters = [AlbumExporter] and i download a.csv is : the date is not readable , and the date in appspot.com admin is : so how to get the full date ?? thanks i change this : class AlbumExporter(bulkloader.Exporter): def __init__(self): bulkloader.Exporter.__init__(self, 'Greeting', [('author', str, None), ('content', str, None), ('date', lambda x: datetime.datetime.strptime(x, '%m/%d/%Y').date(), None), ]) exporters = [AlbumExporter] but the error is :

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  • How to handle concurrency control in ASP.NET Dynamic Data?

    - by Andrew
    I've been quite impressed with dynamic data and how easy and quick it is to get a simple site up and running. I'm planning on using it for a simple internal HR admin site for registering people's skills/degrees/etc. I've been watching the intro videos at www.asp.net/dynamicdata and one thing they never mention is how to handle concurrency control. It seems that DD does not handle it right out of the box (unless there is some setting I haven't seen) as I manually generated a change conflict exception and the app failed without any user friendly message. Anybody know if DD handles it out of the box? Or do you have to somehow build it into the site?

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  • How does the iPhone SDK Core Data system store date types to sqlite?

    - by Andrew Arrow
    I used core data to do this: NSManagedObjectContext *m = [self managedObjectContext]; Foo *f = (Foo *)[NSEntityDescription insertNewObjectForEntityForName:@"Foo" inManagedObjectContext:m]; f.created_at = [NSDate date]; [m insertObject:f]; NSError *error; [m save:&error]; Where the created_at field is defined as type "Date" in the xcdatamodel. When I export the sql from the sqlite database it created, created_at is defined as type "timestamp" and the values look like: 290902422.72624 Nine digits before the . and then some fraction. What is this format? It's not epoch time and it's not julianday format. Epoch would be: 1269280338.81213 julianday would be: 2455278.236746875 (notice only 7 digits before the . not 9 like I have) How can I convert a number like 290902422.72624 to epoch time? Thanks!

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  • The best way to display data in a table view?

    - by LawVS
    Hey guys, I'm trying to display nutritional information in a table view but am struggling about the best way to show the info. I don't want to create unique views for each page as that would take up a lot of space. My ideal avenue would be like a website having links to data pages instead of individual views for each page. How would I best implement that? For example, I would want the first page to be a list of restaurants, then as you press the restaurant it would list the different types of food...the next page would be a list of those foods and then the final page would be the nutrition info itself. Thanks

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  • How do I display non-normalized data in a hierarchical structure?

    - by rofly
    My issue is that I want to display data in a hierarchal structure as so: Democrat County Clerk Candidate 1 Candidate 2 Magistrate Candidate 1 Candidate 2 Candidate 3 But I'm retrieving the dataset like this: Party | Office | Candidate Democrat | County Clerk | Candidate 1 Democrat | County Clerk | Candidate 2 Democrat | Magistrate | Candidate 1 Democrat | Magistrate | Candidate 2 Democrat | Magistrate | Candidate 3 I planned on using nested repeaters, but I need a distinct value of Party, and then distinct values of office name within that party in order to do it. Are there any .NET functions to easily do what I'm attempting to? Would there be a better way of displaying the information other than repeaters? Thanks in advance!

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  • What is the best data structure and algorithm for comparing a list of strings?

    - by Chiraag E Sehar
    I want to find the longest possible sequence of words that match the following rules: Each word can be used at most once All words are Strings Two strings sa and sb can be concatenated if the LAST two characters of sa matches the first two characters of sb. In the case of concatenation, it is performed by overlapping those characters. For example: sa = "torino" sb = "novara" sa concat sb = "torinovara" For example, I have the following input file, "input.txt": novara torino vercelli ravenna napoli liverno messania noviligure roma And, the output of the above file according to the above rules should be: torino novara ravenna napoli livorno noviligure since the longest possible concatenation is: torinovaravennapolivornovilligure Can anyone please help me out with this? What would be the best data structure for this?

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  • Core Data: Fetch all entities in a to-many-relationship of a particular object?

    - by Björn Marschollek
    Hi there, in my iPhone application I am using simple Core Data Model with two entities (Item and Property): Item name properties Property name value item Item has one attribute (name) and one one-to-many-relationship (properties). Its inverse relationship is item. Property has two attributes the according inverse relationship. Now I want to show my data in table views on two levels. The first one lists all items; when one row is selected, a new UITableViewController is pushed onto my UINavigationController's stack. The new UITableView is supposed to show all properties (i.e. their names) of the selected item. To achieve this, I use a NSFetchedResultsController stored in an instance variable. On the first level, everything works fine when setting up the NSFetchedResultsController like this: -(NSFetchedResultsController *) fetchedResultsController { if (fetchedResultsController) return fetchedResultsController; // goal: tell the FRC to fetch all item objects. NSFetchRequest *fetch = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Item" inManagedObjectContext:self.moContext]; [fetch setEntity:entity]; NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; [fetch setSortDescriptors:[NSArray arrayWithObject:sort]]; [fetch setFetchBatchSize:10]; NSFetchedResultsController *frController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetch managedObjectContext:self.moContext sectionNameKeyPath:nil cacheName:@"cache"]; self.fetchedResultsController = frController; fetchedResultsController.delegate = self; [sort release]; [frController release]; [fetch release]; return fetchedResultsController; } However, on the second-level UITableView, I seem to do something wrong. I implemented the fetchedresultsController in a similar way: -(NSFetchedResultsController *) fetchedResultsController { if (fetchedResultsController) return fetchedResultsController; // goal: tell the FRC to fetch all property objects that belong to the previously selected item NSFetchRequest *fetch = [[NSFetchRequest alloc] init]; // fetch all Property entities. NSEntityDescription *entity = [NSEntityDescription entityForName:@"Property" inManagedObjectContext:self.moContext]; [fetch setEntity:entity]; // limit to those entities that belong to the particular item NSPredicate *predicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"item.name like '%@'",self.item.name]]; [fetch setPredicate:predicate]; // sort it. Boring. NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; [fetch setSortDescriptors:[NSArray arrayWithObject:sort]]; NSError *error = nil; NSLog(@"%d entities found.",[self.moContext countForFetchRequest:fetch error:&error]); // logs "3 entities found."; I added those properties before. See below for my saving "problem". if (error) NSLog("%@",error); // no error, thus nothing logged. [fetch setFetchBatchSize:20]; NSFetchedResultsController *frController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetch managedObjectContext:self.moContext sectionNameKeyPath:nil cacheName:@"cache"]; self.fetchedResultsController = frController; fetchedResultsController.delegate = self; [sort release]; [frController release]; [fetch release]; return fetchedResultsController; } Now it's getting weird. The above NSLog statement returns me the correct number of properties for the selected item. However, the UITableViewDelegate method tells me that there are no properties: -(NSInteger) tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section { id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section]; NSLog(@"Found %d properties for item \"%@\". Should have found %d.",[sectionInfo numberOfObjects], self.item.name, [self.item.properties count]); // logs "Found 0 properties for item "item". Should have found 3." return [sectionInfo numberOfObjects]; } The same implementation works fine on the first level. It's getting even weirder. I implemented some kind of UI to add properties. I create a new Property instance via Property *p = [NSEntityDescription insertNewObjectForEntityForName:@"Property" inManagedObjectContext:self.moContext];, set up the relationships and call [self.moContext save:&error]. This seems to work, as error is still nil and the object gets saved (I can see the number of properties when logging the Item instance, see above). However, the delegate methods are not fired. This seems to me due to the possibly messed up fetchRequest(Controller). Any ideas? Did I mess up the second fetch request? Is this the right way to fetch all entities in a to-many-relationship for a particular instance at all?

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  • How do you delete a core data entry from the detail view?

    - by Sam
    I am working with an app similar to apple's core data recipes sample code. I want to be able to delete the entry from the detail view, much like apple's contacts app. The code below is deleting the 1st entry and not the selected entry. Not sure what I am doing wrong. NSIndexPath *indexPath = [myTableView indexPathForSelectedRow]; NSManagedObjectContext *context = [fetchedResultsController managedObjectContext]; [context deleteObject:[fetchedResultsController objectAtIndexPath:indexPath]]; [myTableView reloadData];

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  • What should i do for accomodating large scale data storage and retrieval?

    - by kailashbuki
    There's two columns in the table inside mysql database. First column contains the fingerprint while the second one contains the list of documents which have that fingerprint. It's much like an inverted index built by search engines. An instance of a record inside the table is shown below; 34 "doc1, doc2, doc45" The number of fingerprints is very large(can range up to trillions). There are basically following operations in the database: inserting/updating the record & retrieving the record accoring to the match in fingerprint. The table definition python snippet is: self.cursor.execute("CREATE TABLE IF NOT EXISTS `fingerprint` (fp BIGINT, documents TEXT)") And the snippet for insert/update operation is: if self.cursor.execute("UPDATE `fingerprint` SET documents=CONCAT(documents,%s) WHERE fp=%s",(","+newDocId, thisFP))== 0L: self.cursor.execute("INSERT INTO `fingerprint` VALUES (%s, %s)", (thisFP,newDocId)) The only bottleneck i have observed so far is the query time in mysql. My whole application is web based. So time is a critical factor. I have also thought of using cassandra but have less knowledge of it. Please suggest me a better way to tackle this problem.

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  • Access data of a XSL file from a JSF...

    - by Asela
    Hi all, I'm having 2 simple XML & XSL files as follows. form_1.xml <?xml version="1.0" encoding="windows-1252"?> <?xml-stylesheet type="text/xsl" href="form_1.xsl"?> <myform> </myform> form_1.xsl <?xml version="1.0" encoding="windows-1252"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="myform"> <html> <body> <form> <div align="center"> <h2>My first form in XSL</h2> <table cellspacing="1" cellpadding="1"> <tr> <td>First name : </td> <td> <input type="text"></input> </td> </tr> <tr> <td>Last name : </td> <td> <input type="text"></input> </td> </tr> <tr> <td>Address : </td> <td> <input type="text"></input> </td> </tr> </table> </div> </form> </body> </html> </xsl:template> </xsl:stylesheet> Now I have a JSF file where I have embeded the form_1.xml file inside an iFrame. Inside my JSF, I have submit & reset buttons as follows. myJsf.xhtml <!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" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:utils="http://java.sun.com/jsf/composite/utils"> <h:head> <title>::: The form filler application :::</title> <link href="./css/styles.css" rel="stylesheet" type="text/css" /> </h:head> <h:body> <div align="center"> <table cellspacing="2" cellpadding="2"> <tr> <th class="title">&nbsp; My form filler &nbsp;</th> </tr> </table> <br /> <fieldset><legend>Fill appropriate data in the following form</legend> <h:form> <div align="center"> <table> <tr> <td colspan="2"><iframe src="form_1.xml" frameborder="0" width="500px" height="500px"></iframe></td> </tr> <tr></tr> <tr> <td align="right"><h:commandButton value="Save data" action="#{myManagedBean.printValuesEnteredInTheForm}" /></td> <td align="left"><h:commandButton type="reset" value="Clear" /></td> </tr> </table> </div> </h:form></fieldset> </div> </h:body> </html> Now my question is that upon clicking the Submit button in my JSF, how do I access the values which I have entered in the XSL file? Any help is greatly appreciated. Thanks in advance. Reagrds, Asela.

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  • NSArrayController that is sorted and unique (no duplicates) for use in a pop-up in a core-data app

    - by Douglas Weaver
    I have core data app with an entity OBSERVATION that has as one of its attributes DEALNAME. I want to reference through Interface Builder or by making custom modifications to an NSArrayController a list of unique sorted dealnames so that I can use them in a pop-up. I have attempted to use @distinctUnionOfSets (and @distinctUnionOfArrays) but am unable to locate the proper key sequence. I can sort the ArrayController by providing a sort descriptor, but do not know how to eliminate duplicates. Are the @distinct... keys the right methodology? It would seem to provide the easiest way to optimize the use of IB. Is there a predicate form for removing duplicates? Or do I need to use my custom controller to extract an NSSet of the specific dealnames, put them back in an array and sort it and reference the custom array from IB? Any help would be appreciated. I am astounded that other have not tried to create a sorted-unique pop-up in tableviews.

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  • Sharepoint 2007 : Saving Form data with page redirection using custom parameters.

    - by Deepu
    HI Experts, After saving the form data I would like to REDIRECT to different pages based on the @Status value using the input type button. <input type="button" value="Save" name="btnSave" id="btnSave" onclick="{ddwrt:GenFireServerEvent('_commit;_redirect={*Confirm.aspx?ID=1}')};" /* if @Status == "Draft" url = "draft.aspx ? ID = " @ID else if @Status == "Save" url = "save.aspx ? ID = " @ID else url = "confirm.aspx ? ID = " @ID Here @ID and @Status are share point list column names Now I have hard-coded the url Confirm.aspx?ID=4. But I want to check the status value using XSLT condition and set different URL name with @ID value.. How do I achieve this.. any help would be appreciated.. thanks deepu

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  • Can I create a transaction using ADO NET Entity Data Model?

    - by Junior Mayhé
    Hi is it possible on the following try-catch to execute a set of statements as a transaction using ADO NET Entity Data Model? [ValidateInput(false)] [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Customer c) { try { c.Created = DateTime.Now; c.Active = true; c.FullName = Request.Form["FirstName"]; db.AddToCustomer(c); db.SaveChanges(); Log log = new Log();//another entity model object log.Created = DateTime.Now; log.Message = string.Format(@"A new customer was created with customerID {0}", c.CustomerID); db.AddToLog(log); db.SaveChanges(); return RedirectToAction("CreateSuccess", "Customer"); } catch { return View(); } } Any thoughts would be very appreciated.

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  • Which data structure(s) to back a Final Fantasy ATB-style queue? (a delay queue)

    - by ZoFreX
    Situation: There are several entities in a simulated environment, which has an artificial notion of time called "ticks", which has no link to real time. Each entity takes it in turns to move, but some are faster than others. This is expressed by a delay, in ticks. So entity A might have a delay of 10, and B 25. In this case the turn order would go: A A B A A I'm wondering what data structure to use. At first I automatically thought "priority queue" but the delays are relative to "current time" which complicates matters. Also, there will be entities with larger delays and it's not unforseeable that the program will run through millions of ticks. It seems silly for an internal counter to be building higher and higher when the delays themselves stay relatively small and don't increase. So how would you solve this?

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  • How to verify if two tables have exactly the same data?

    - by SiLent SoNG
    Basically we have one table (original table) and it is backed up into another table (backup table); thus the two tables have exactly the same schema. At the beginning both tables (original table and backup table) contains exactly the same set of data. After sometime for some reason I need to verify whether dataset in the original table has changed or not. In order to do this I have to compare the dataset in the original table against the backup table. Let's say the original table has the following schema: `create table LemmasMapping ( lemma1 int, lemma2 int, index ix_lemma1 using btree (lemma1), index ix_lemma2 using btree (lemma2) )` How could I achieve the dataset comparision? Update: the table does not have a primary key. It simply stores mappings between two ids.

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  • Can a Perl subroutine return data but keep processing?

    - by Perl QuestionAsker
    Is there any way to have a subroutine send data back while still processing? For instance (this example used simply to illustrate) - a subroutine reads a file. While it is reading through the file, if some condition is met, then "return" that line and keep processing. I know there are those that will answer - why would you want to do that? and why don't you just ...?, but I really would like to know if this is possible. Thank you so much in advance.

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  • Stopping the manipulation of variables used for data collection?

    - by Ruinous
    I am working on a project in java and I was hoping to be able to collect statistics from the client and a possible problem that I fear will occur is the manipulation of the variables used for collection which will lead to illegitimate statistics. Is it in any way possible to prevent the manipulation of variables or is it always possible? For example: I want to log the actions made per hour from the client. The variable acting as a counter for the amount of actions performed is manipulated and a much larger amount is added to the counter. This data is then uploaded to the server (Of course using a multi-tier architecture to prevent even more possible problems) and considered 'legit.' Is there any way to prevent this?

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  • How should I store Dynamically Changing Data into Server Cache?

    - by Scott
    Hey all, EDIT: Purpose of this Website: Its called Utopiapimp.com. It is a third party utility for a game called utopia-game.com. The site currently has over 12k users to it an I run the site. The game is fully text based and will always remain that. Users copy and paste full pages of text from the game and paste the copied information into my site. I run a series of regular expressions against the pasted data and break it down. I then insert anywhere from 5 values to over 30 values into the DB based on that one paste. I then take those values and run queries against them to display the information back in a VERY simple and easy to understand way. The game is team based and each team has 25 users to it. So each team is a group and each row is ONE users information. The users can update all 25 rows or just one row at a time. I require storing things into cache because the site is very slow doing over 1,000 queries almost every minute. So here is the deal. Imagine I have an excel spreadsheet with 100 columns and 5000 rows. Each row has two unique identifiers. One for the row it self and one to group together 25 rows a piece. There are about 10 columns in the row that will almost never change and the other 90 columns will always be changing. We can say some will even change in a matter of seconds depending on how fast the row is updated. Rows can also be added and deleted from the group, but not from the database. The rows are taken from about 4 queries from the database to show the most recent and updated data from the database. So every time something in the database is updated, I would also like the row to be updated. If a row or a group has not been updated in 12 or so hours, it will be taken out of Cache. Once the user calls the group again via the DB queries. They will be placed into Cache. The above is what I would like. That is the wish. In Reality, I still have all the rows, but the way I store them in Cache is currently broken. I store each row in a class and the class is stored in the Server Cache via a HUGE list. When I go to update/Delete/Insert items in the list or rows, most the time it works, but sometimes it throws errors because the cache has changed. I want to be able to lock down the cache like the database throws a lock on a row more or less. I have DateTime stamps to remove things after 12 hours, but this almost always breaks because other users are updating the same 25 rows in the group or just the cache has changed. This is an example of how I add items to Cache, this one shows I only pull the 10 or so columns that very rarely change. This example all removes rows not updated after 12 hours: DateTime dt = DateTime.UtcNow; if (HttpContext.Current.Cache["GetRows"] != null) { List<RowIdentifiers> pis = (List<RowIdentifiers>)HttpContext.Current.Cache["GetRows"]; var ch = (from xx in pis where xx.groupID == groupID where xx.rowID== rowID select xx).ToList(); if (ch.Count() == 0) { var ck = GetInGroupNotCached(rowID, groupID, dt); //Pulling the group from the DB for (int i = 0; i < ck.Count(); i++) pis.Add(ck[i]); pis.RemoveAll((x) => x.updateDateTime < dt.AddHours(-12)); HttpContext.Current.Cache["GetRows"] = pis; return ck; } else return ch; } else { var pis = GetInGroupNotCached(rowID, groupID, dt);//Pulling the group from the DB HttpContext.Current.Cache["GetRows"] = pis; return pis; } On the last point, I remove items from the cache, so the cache doesn't actually get huge. To re-post the question, Whats a better way of doing this? Maybe and how to put locks on the cache? Can I get better than this? I just want it to stop breaking when removing or adding rows.

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  • Is there a name for a pure-data Objective-C class?

    - by BrianEnigma
    This is less of a code-specific question and more of an Objective-C nomenclature question. In C you have struct for pure data. In Enterprise Java, you have "bean" classes that are purely member variables with getters and setters, but no business logic. In Adobe FLEX, you have "Value Objects". In Objective-C, is there a proper name for an object (descended from NSObject, of course) that simply has ivars and getters/setters (or @property/@synthesize, if you want to get fancy) and no real business logic? A more concrete example might be a simple class with getters and setters for filename, file size, description, and assorted other metadata. You could then take a bunch of these and easily throw them into a container (NSDictionary, NSArray) without the need for messy NSValue wrapping of a C struct. It is also a little more structure than putting, say, a bunch of loosely-typed child NSDictionaries into a parent container object.

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