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POQuery SQLite array after update
 

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  1. POQuery SQLite array after update
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    <p>I have a tab bar application with 2 UITableViews. In Tab 1 I have a UITableView populated with an array of Todo objects from an Sqlite database. Each Todo object has a status which can be updated by a button in it's detail view; 'complete' or 'in progress' - this then updates the SQlite database with a '1' if a Todo object has been marked as 'complete' or a '0' if it is marked as 'in progress'. This works fine I think (although it doesn't persist after quitting the application).</p> <p>However, in Tab 2 I have another UITableView which I want to show only the items that have been marked as 'complete'.</p> <p>Would this require another seperate Sqlite call (select * from todo where complete='1'), and then a seperate array of TodoFav objects to populate the table in Tab 2? If so how would Tab 2 know that Tab 1 has been updated and saved? — I think currently it only saves on exit (although again this doesn't seem to persist after a quit).</p> <p>Any help would be greatly appreciated, I have been a lurker for a while now, and have searched long and hard for the answer to no avail! Many thanks.</p> <p><strong>Edit</strong>:</p> <p>Dehydrate code to save update on exit:</p> <pre><code>- (void) dehydrate { if (dirty) { // If the todo is “dirty” meaning the dirty property was set to YES, we will need to save the new data to the database. if (dehydrate_statment == nil) { const char *sql = "UPDATE todo SET priority = ?,complete =? WHERE pk=?"; if (sqlite3_prepare_v2(database, sql, -1, &amp;dehydrate_statment, NULL) != SQLITE_OK) { NSAssert1(0, @"Error: failed to prepare statement with message '%s'.", sqlite3_errmsg(database)); } } // Bind our variables to each of the “?”‘s. Notice the order. // The numbers represent the question marks from left to right (1 being the first, 2 being the second, 3 being the third) sqlite3_bind_int(dehydrate_statment, 3, self.primaryKey); sqlite3_bind_int(dehydrate_statment, 2, self.status); sqlite3_bind_int(dehydrate_statment, 1, self.priority); int success = sqlite3_step(dehydrate_statment); if (success != SQLITE_DONE) { NSAssert1(0, @"Error: failed to save priority with message '%s'.", sqlite3_errmsg(database)); } sqlite3_reset(dehydrate_statment); dirty = NO; } } </code></pre> <p>And code for button to change to complete:</p> <pre><code>- (void)updateStatus:(NSInteger)newStatus { self.status = newStatus; dirty = YES; // Signifies that the todo has been altered and will need to be saved to the database. } </code></pre> <p>Trying to query the database a second time for 'completed' (status='1') items:</p> <pre><code>- (NSMutableArray *)todosComplete { NSMutableArray *todoCompleteArray = [[NSMutableArray alloc] init]; self.todosComplete = todoCompleteArray; [todoCompleteArray release]; NSMutableArray *retval = [[[NSMutableArray alloc] init] autorelease]; NSString *query = @"select * from todo where status='1'"; sqlite3_stmt *statement; if (sqlite3_prepare_v2(database, [query UTF8String], -1, &amp;statement, nil) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { int primaryKey = sqlite3_column_int(statement, 0); TodoComplete *tdC = [[TodoComplete alloc] initWithPrimaryKey:primaryKey database:database]; [todosComplete addObject:tdC]; [tdC release]; } sqlite3_finalize(statement); } return retval; </code></pre> <p>}</p> <p>One last thing, initialization in app delegate, seems to work fine:</p> <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. [self createEditableCopyOfDatabaseIfNeeded]; [self initializeDatabase]; //[self initializeDatabaseFiltered]; // Add the navigation controller's view to the window and display. [self.window addSubview:navigationController.view]; [self.window addSubview:tabController.view]; [self.window makeKeyAndVisible]; return YES; </code></pre> <p>}</p> <p>Thanks again!!! Sorry for the long post, really appreciate any help. I know I'm missing something obvious - dehydrate needs to be instant for a start? And I'm probably not querying the db correctly for the filtered items or something!?</p>
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    1. USmedley
    1. USmedley
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    1. CO"I know I'm missing something obvious" - yes, yes you are. You're missing [FMDB](http://github.com/ccgus/FMDB), a wrapper around sqlite for objective c that makes all this `sqlite3_prepare_v2` crap unnecessary. I guarantee that if you use FMDB, 99% of your sqlite issues will magically go away.
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      1. POQuery SQLite array after update
      1. USDave DeLong
    2. COHi, thanks.. I've had a look at FMDB a couple of times but figuring out how to actually use it was as time consuming as trying to work with SQLite directly.
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      1. USmedley
 

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