TableView crashes when scrolling, getting the Data from SQLite.

[ZeRo]

Hi,
could someone please help me? I've been trying to create a own Database class for my TableViews so I don't have to open my Database each time I have a new TableView.

In my Database class i have a method which takes a NSString, the sql query and returns an NSMutableArray.
When I then open my TableView the first time, everything works fine, but when i start scrolling the data seems to be gone. And my App crashes.

With NSZombies i get this Error:
-[StateTableViewController tableView:cellForRowAtIndexPath:]: message sent to deallocated instance 0x5c6a5c0

Please help me!

Database.h

#import <Foundation/Foundation.h>
#import <sqlite3.h>

@interface Database : NSObject {
   NSMutableArray *result;
   sqlite3 *database;
   sqlite3_stmt *statement;
}

+ (Database *)sharedDatabase;
- (NSMutableArray *)query:(NSString *)stmt;
@end

Database.m

#import "Database.h"

static Database *sharedInstance;

@implementation Database

- (id)init {
   
   //Initiation Database, everything works fine
   
   return self;
}

+ (Database *)sharedDatabase {
   NSLog(@"picking shared Database");
   return sharedInstance;
}

- (NSMutableArray *)query:(NSString *)stmt {
   [result removeAllObjects];
   if (!statement) {
      const char *cQuery = [stmt cStringUsingEncoding:NSUTF8StringEncoding];
      
      if (sqlite3_prepare_v2(database, cQuery, -1, &statement, NULL) != SQLITE_OK) {
         NSLog(@"query error: %s", statement);
      } else {
         NSLog(@"Statement OK!");
      }
   }
   
   while (sqlite3_step(statement) == SQLITE_ROW) {
      const char *cStateName = (const char *)sqlite3_column_text(statement, 1);
      NSString *stateName = [[[NSString alloc] initWithUTF8String:cStateName] autorelease];
      
      NSInteger iStateId = sqlite3_column_int(statement, 0);
      NSNumber *nStateId = [NSNumber numberWithInt:iStateId];
      
      NSDictionary *stateDict = [[NSDictionary alloc] initWithObjectsAndKeys:nStateId,@"id",
                               stateName,@"name", nil]; 
      
      [result addObject:stateDict];
      [stateDict release];
      NSLog(@"%@, %@", nStateId, stateName);
   }
   sqlite3_reset(statement);
   return result;
}
@end

My TableView.h

#import <UIKit/UIKit.h>

@interface StateTableViewController : UIViewController <UITableViewDelegate> {
   IBOutlet UITableView *stateTable;
   NSMutableArray *states;
}
@end

TableView.m

#import "StateTableViewController.h"
#import "Database.h";

@implementation StateTableViewController

#pragma mark -
#pragma mark init
- (id)init {
   //...      
   states = [[NSMutableArray alloc] initWithArray:[[Database sharedDatabase] query:@"SELECT id, name FROM States ORDER BY name"]];

   return self;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
   return [states count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)ip {
   
   NSDictionary *stateDict = [states objectAtIndex:[ip row]];
   NSString *name = [stateDict objectForKey:@"name"];
   
   UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"UITableViewCell"];
   
   if (!cell) {
      cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault 
                             reuseIdentifier:@"UITableViewCell"];
      [cell autorelease];
   }
   [[cell textLabel] setText:name];
   return cell;
}

@end

And please feel free to correct every other mistake I made, or things you usually do different when you are programming for a iphone app. I'm quite new to this topic. Thanks!!