How do I archive an NSArray of NSDictionary (with NSCoding)?

Suppose I am holding data in an array like this

wordList = 开发者_运维百科[[NSMutableArray alloc] init];
while ([rs next])     //Some database return loop
{
    wordDict = [[NSMutableDictionary alloc] init];

    [wordDict setObject:[NSNumber numberWithInt:[rs intForColumn:@"id"]] forKey:@"id"];
    [wordDict setObject:[rs stringForColumn:@"word"] forKey:@"word"];

    [wordList addObject: wordDict];

    [wordDict release];
    wordDict = nil;
}

But I want to store this result (i.e. wordList) in SQLite for later use - I guess using NSCoding. How would I do that? (Feel free to point out any errors in how stuff is being alloc'ed if there are problems there).

If you don’t insist on serialization using NSCoding, there’s a writeToFile:atomically: method both on NSArray and NSDictionary. This will serialize your object into a property list (*.plist). The only catch is that all the objects in the “tree” to be serialized must be NSString, NSData, NSArray, or NSDictionary (see the documentation). I’m not sure how NSNumber fits in, but with a bit of luck it will be serialized and deserialized too. The inverse method that will turn the file back into a dictionary or an array is called initWithContentsOfFile:.

As for your code, I would just use the [NSMutableDictionary dictionary] convenience method that gets you an autoreleased dictionary. It’s shorter than the usual alloc & init and you save one line for the explicit release.