SQLite Not Importing Properly into iOS

Question

It appears that when I copy a .sqlite3 file into iOS, and use FMDB to access it, the database is empty. I just drag and drop it into Xcode. When I run:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"db.sqlite3"];
FMDatabase *db = [FMDatabase databaseWithPath:writableDBPath];

FMResultSet *results = [db executeQuery:@"SELECT * FROM tableName"];

results returns nil. Looking at [db lastErrorMessage], it says my table does not exist. When I open up the .sqlite file in the command line (the one that is stored in the iPhone Simulator), I get an empty database. Is there a specific way to import a SQLite database into iOS? If so, how?

Answer 1

I see two likely problems:

First, make sure the .sqlite file is included in your project target. Select your file in the File Navigator; open the Utilities panel (the right hand panel icon in the section that says "View"), and look for a section titled "Target Membership". If the box for your desired target (you probably only have one) is not checked, your database file is not being copied into the bundle.

Second, you are attempting to find the database in your documents directory. However, you must manually copy it from your bundle to that directory before you can open it as a writable file:

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"db.sqlite3"];

NSURL *dbURL = [NSURL fileURLWithPath:dbPath];

// copy a database from the bundle if not present
// on disk
NSFileManager *fm = [NSFileManager defaultManager];
if (![fm fileExistsAtPath:dbPath]) {
    NSURL *bundlePath = [[NSBundle mainBundle] URLForResource:@"db" withExtension:@"sqlite3"];
    NSError *error = nil;
    if (!bundlePath || ![fm copyItemAtURL:bundlePath toURL:dbURL error:&error]) {
        NSLog(@"error copying database from bundle: %@", error);
    }
}