NSArray SQL representation

[pwightman]

Hey,

First of all, thanks for the great library. I plan on contributing some, I've started to make a set of methods I've found useful in my project that I'll pull request at some point so you can take a look.

I have a question about SQL representation. You have this in the wiki:

@implementation NSString (sqlRepresentation)

+ (ActiveRecord *)fromSql:(NSString *)sqlData{
    return sqlData;
}

- (NSString *)toSql {
    return self;
}

+ (const char *)sqlType {
    return "text";
}

@end 

You have fromSql returning ActiveRecord, would it not return NSString? Am I misunderstanding how this works?

I'm setting up sql representation for NSArray. All array will just contain BOOLs, something like this:

NSArray *values = @[ @YES, @NO, @NO, @YES ];

My storage technique is just to serialize the data as JSON and back again. Here's the code:

@implementation NSArray (BBExtension)

+ (id)fromSql:(NSString *)sqlData{
    return [NSJSONSerialization JSONObjectWithData:[sqlData dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil];
}

- (NSString *)toSql {
    return [NSString stringWithUTF8String:[[NSJSONSerialization dataWithJSONObject:self options:0 error:nil] bytes]];
}

+ (const char *)sqlType {
    return "text";
}

@end

I've tested the serialization/deserialization to verify that when I manually do it, it works fine. But when creating the record like so:

BBGroove *groove = [[BBGroove alloc] init];

...

[groove save]; // This returns YES

NSLog(@"Groove: %@", [BBGroove allRecords]);

After the NSLog runs, I get this in the console:

2012-07-29 19:54:55.896 BeatBuilder[3479:c07] SELECT "BBGroove"."id","BBGroove"."updatedAt","BBGroove"."beatUnit","BBGroove"."beats","BBGroove"."tempo","BBGroove"."createdAt","BBGroove"."voices" FROM "BBGroove"  LIMIT -1 
2012-07-29 19:54:55.897 BeatBuilder[3479:c07] Couldn't retrieve data from database: no such table: BBGroove
2012-07-29 19:54:55.923 BeatBuilder[3479:c07] Groove: (null)

My other models work just fine, but this one model has the custom ARRepresentationProtocol for arrays and doesn't work, so I can't help but think I might be doing something wrong? Do you see something I'm overlooking?

I'll keep looking into it, but wondered if you had some insight. Thanks for the great work!

[pwightman]

Oh, as an aside I'm running Mac OSX 10.8/Xcode 4.5.

[pwightman]

Ah, I think I've figured it out. I didn't see that I was getting errors even earlier:

2012-07-29 20:23:27.493 BeatBuilder[3661:c07] Couldn't execute query create table "BBGroove"(id integer primary key unique , "voices" text, "tempo" (null), "beatUnit" (null), "beats" (null), "updatedAt" INTEGER, "createdAt" INTEGER) : near "(": syntax error

I think because I have non-object properties:

@property (nonatomic, assign) NSUInteger tempo;
@property (nonatomic, assign) BBGrooverBeat beatUnit;
@property (nonatomic, assign) NSUInteger beats;

BBGrooverBeat is an enum. Are non-object properties just not supported since you can't add a class extension to them?

[pwightman]

Some progress, but here's what I'm getting now. My class setup is below:

@interface BBGroove : ActiveRecord

@property (nonatomic, strong) NSArray *voices;
@property (nonatomic, strong) NSNumber *tempo;
@property (nonatomic, strong) NSNumber *beatUnit;
@property (nonatomic, strong) NSNumber *beats;

...

@end

And the .m file:

@implementation BBGroove

ignore_fields_do(
                 ignore_field(voices)
)

...

@end

So all that should be saved is the 3 NSNumber objects, but this code:

BBGroove *groove = ...;

if(![groove save]) {
        NSLog(@"FAILED: %@", [groove errors]);
    }

NSLog(@"Groove: %@", groove);

gives me this:

2012-07-29 20:38:14.342 BeatBuilder[4042:c07] Groove: BBGroove
tempo => 120;beatUnit => 4;beats => 4;id => (null);updatedAt => 2012-07-30 02:38:12 +0000;createdAt => 2012-07-30 02:38:12 +0000;

Now only id is null, though updateAt/createdAt are set and save is returning YES? Still investigating...

[pwightman]

Fixed! I ... my BBGroove creation, which was exactly the problem! alloc/init instead of newRecord. All is well now!

[AlexDenisov]

Hi, thanks for feedback. Yes, the problem is at alloc/init methods. Scalar types are not supported yet, but it should be soon. Also, note that NSArray already have implemented toSql method, it useful with WHERE statements

NSArray *ids = [NSArray arrayWithObjects:
           [NSNumber numberWithInt:1],
           [NSNumber numberWithInt:15], 
           nil];
NSString *username = @"john";
ARLazyFetcher *fetcher = [User lazyFetcher];
[fetcher where:@"'user'.'name' = %@ or 'user'.'id' in %@", 
               username, ids, nil];

If you want to store NSArray as as table field you should try that trick

Describe your NSArray as ignored and add your NSArray representation

@interface Model : ActiveRecord
@property (nonatomic, retain) NSArray *fuuBar;
@property (nonatomic, copy) NSString *fuuBarRepresentation;
@end
...
@implementation Model
ignore_fields_do(
             ignore_field(fuuBar)
)
...
- (BOOL)save {
    //   convert fuuBar array to fuuBarRepresentation
    return [super save];
}
@end

Or just use KVO and convert fuuBar <-> fuuBarRepresentation on each changes.

And last variant that I see - use another record instead array.

[pwightman]

Ah, I like the save override. Good call, I think I'll switch to that. Thanks!