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PORecreate persistence store after removing previous sqlite store file
 

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  1. PORecreate persistence store after removing previous sqlite store file
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    <p>I would like to remove my sql lite file and set up the persistance store again. </p> <pre><code>//Explicitly write Core Data accessors - (NSManagedObjectContext *) managedObjectContext { if (managedObjectContext != nil) { return managedObjectContext; } NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { managedObjectContext = [[NSManagedObjectContext alloc] init]; [managedObjectContext setPersistentStoreCoordinator: coordinator]; } return managedObjectContext; } - (void) setManagedObjectContext:(NSManagedObjectContext *)managedObjectContext{} - (NSManagedObjectModel *)managedObjectModel { if (managedObjectModel != nil) { return managedObjectModel; } managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil] ; return managedObjectModel; } -(void) setManagedObjectModel:(NSManagedObjectModel *)managedObjectModel{} - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { if (persistentStoreCoordinator != nil) { return persistentStoreCoordinator; } NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Port.sqlite"]]; NSError *error = nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if(![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&amp;error]) { NSLog(@"Could not create store .... %@", error ); /*Error for store creation should be handled in here*/ } return persistentStoreCoordinator; } </code></pre> <p>I am trying to reset my scene like this </p> <pre><code>- (void)reset { // Release CoreData chain self.managedObjectContext = nil; self.managedObjectModel = nil; self.persistentStoreCoordinator = nil; // Delete the sqlite file NSError *error = nil; NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Port.sqlite"]]; if ([fileManager fileExistsAtPath:storeUrl.path]){ [fileManager removeItemAtURL:storeUrl error:&amp;error]; } self.managedObjectContext = [self managedObjectContext]; self.managedObjectModel = [self managedObjectModel]; self.persistentStoreCoordinator = [self persistentStoreCoordinator]; // handle error... } </code></pre> <p>I am getting an error while saving:</p> <pre><code>+ (BOOL)saveAll { // [self createStorage]; NSError *error = nil; NSManagedObjectContext *managedObjectContext = [(WSSMobileAppsAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; if (![managedObjectContext save:&amp;error]) { NSLog(@"Error while saving %@", error); return FALSE; } return TRUE; } </code></pre> <p>The error:</p> <pre><code>Error while saving Error Domain=NSCocoaErrorDomain Code=134030 "The operation couldn’t be completed. (Cocoa error 134030.)" UserInfo=0x7195ac0 {NSAffectedStoresErrorKey=( "&lt;NSSQLCore: 0x714eee0&gt; (URL: file://localhost/Users/.../Library/Application%20Support/iPhone%20Simulator/5.0/Applications/CEDB9019-1D64-4968-9BE7-57E1493B96EC/Documents/Port.sqlite)" ), NSUnderlyingError=0x7195a50 "The operation couldn’t be completed. (Cocoa error 4.)", NSFilePath=/Users/.../Library/Application Support/iPhone Simulator/5.0/Applications/CEDB9019-1D64-4968-9BE7-57E1493B96EC/Documents/Port.sqlite} </code></pre> <p>I only get the error if I run my reset function. I thought that setting: </p> <pre><code>self.managedObjectContext = nil; self.managedObjectModel = nil; self.persistentStoreCoordinator = nil; </code></pre> <p>...would solve the problem. Then everything would be recreated. Please help. </p> <hr> <p>Thank you very much for your answers. Now there is no error but nothing gets stored if I run my reset. I do a fetch right after saving </p> <pre><code>if (![managedObjectContext save:&amp;error]) { NSLog(@"Error while saving %@", error); return FALSE; } CoreDataPortService *c = [[CoreDataPortService alloc] init]; NSLog(@"Saved all.... got number of ports ... %d", [[c getPorts] count]); </code></pre> <p>I if don't run my reset method everything works as expected. What can be wrong?</p>
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    1. USBill the Lizard
    1. USpethel
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      1. PORecreate persistence store after removing previous sqlite store file
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    1. COI thought the point was you wanted to delete all your data. No? If you delete the file, and delete the managedObjectContext in memory, the data is gone. If you're trying to delete the file and recreate it from the contents of memory, then you would need a different approach. I can't really imagine why you would want to do that. The persistent store will keep in sync with what you have in the managed object context in normal cases.
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      1. USmorningstar
    2. COI would like to delete the data. Is it possible to also delete the file. Thats because sometimes I change entities.
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      1. USpethel
    3. COYou said, "nothing gets stored if I run my reset". It sounds like you want nothing stored, i.e. everything deleted. Do you mean you run reset, then add objects, then save, and there are no objects after that?
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      1. USmorningstar
 

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