Question

I’m trying to use sqlite in a ‘data services’ class like below. I keep getting an error code 1 when calling ‘sqlite3_prepare_v2’. The logs certainly back up that the database is getting opened before my recipeNames function is called. I’m so stumped! Is it a memory management thing with the sqlite3 *db ? Eg is it getting freed when i don’t want it to?

I’m certain the code is OK otherwise, because if i put the sqlite_open in the recipeNames function, it works great. It’s just if i try to open it in the init method it fails. Thanks a lot guys.

My header:

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


@interface DataServices : NSObject {
    sqlite3 *db;
    int dbrc;
}

- (NSMutableArray *) recipeNames;

@end

Implementation file:

#import "DataServices.h"
#import "MenuMakerAppDelegate.h"
#include <sqlite3.h>

@implementation DataServices

- (id)init {
    [super init];

    // my init stuff here

    // Get the database name
    const char *dbPathUtf8 = [((MenuMakerAppDelegate*)[UIApplication sharedApplication].delegate).dbFilePath UTF8String];
    // Open the database
    NSLog(@"opening db");
    sqlite3_open (dbPathUtf8, &db);
    NSLog(@"opened db");

    return self;
}

- (void)dealloc {
    // My dealloc stuff here
    NSLog(@"Closing DB");
    sqlite3_close(db);
    [super dealloc];
}

- (NSMutableArray *) recipeNames {
    // Create the empty array to return
    NSMutableArray *arr = [[[NSMutableArray alloc] init] autorelease];
    // The SQL
    NSString *sql = @"select recipe from recipes";
    const char *sqlUtf8 = [sql UTF8String];
    // Make the prepared statement (like C# SqlCommand)
    sqlite3_stmt *dbps;
    dbrc=sqlite3_prepare_v2(db, sqlUtf8, -1, &dbps, NULL); // FAILS HERE !!!
    if (dbrc) NSLog(@"Prepare!!! %d", dbrc);
    // Loop thru rows
    while (sqlite3_step(dbps) == SQLITE_ROW) {
        NSString *recipe = [NSString stringWithUTF8String:(char*)sqlite3_column_text(dbps,0)];
        [arr addObject:recipe];
    }
    // Get rid of the command
    sqlite3_finalize(dbps);
    // Return the array that was autoreleased before
    return arr;
}

@end

Answer 1

On a hunch:

NSLog(@"opening db %s", dbPathUtf8);
int result = sqlite3_open(dbPathUtf8, &db);
NSLog(@"sqlite3_open returned %d", result);

I’m betting that dbPathUtf8 is null and that sqlite3_open is returning an error. 1 is SQLITE_ERROR (SQL error or missing database), which probably means db is NULL.