how to connect Database in IOS

- (void) copyDatabaseIfNeeded
{
    
    NSFileManager *fileManager = [NSFileManager defaultManager];
	NSError *error;
	NSString *dbPath = [self getDBPath];
	BOOL success = [fileManager fileExistsAtPath:dbPath];
	
	if(!success)
	{
		NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"calender.sqlite"];
		success = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:&error];
		if (!success)
			NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
	}
}

- (NSString *) getDBPath
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
	NSString *documentsDir = [paths objectAtIndex:0];
	return [documentsDir stringByAppendingPathComponent:@"calender.sqlite"];
}


And this two methods for inserting and selecting:

- (void)addNEW
{
    NSString *path = [am getDBPath];
    if (sqlite3_open([path UTF8String], &database) == SQLITE_OK)
    {
        NSString *querySQL = [NSString stringWithFormat:@"insert into Task (task,buttontag) Values ('%@','%@')",textField.text,btntag];
        const char *sql = [querySQL UTF8String];
        sqlite3_stmt *searchStatement;
        if (sqlite3_prepare_v2(database, sql, -1, &searchStatement, NULL) == SQLITE_OK)
        {
            while (sqlite3_step(searchStatement) == SQLITE_ROW)
            {
                
            }
            am.task_ID = sqlite3_last_insert_rowid(database);
        }
        sqlite3_finalize(searchStatement);
    }
}



-(void) getselectedtask: (NSString *) btnTag
{
    AppDelegate *app = (AppDelegate *)[[UIApplication sharedApplication] delegate];  
    NSString *path = [app getDBPath];    
    if (sqlite3_open([path UTF8String], &database) == SQLITE_OK)
    {
        NSString *querySQL = [NSString stringWithFormat:@"SELECT * from schedule  WHERE buttontag='%@'",btnTag];
        const char *sql = [querySQL UTF8String];
        sqlite3_stmt *searchStatement;
        
        if (sqlite3_prepare_v2(database, sql, -1, &searchStatement, NULL) == SQLITE_OK)
        {
            while (sqlite3_step(searchStatement) == SQLITE_ROW)
            {
                ObjectClass *obj = [[ObjectClass alloc] init];
                obj.startingHr = [NSString stringWithUTF8String:(char *)sqlite3_column_text(searchStatement, 1)];
                NSString *sched_ID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(searchStatement, 7)];
            }
        }
        sqlite3_finalize(searchStatement);
    }
}