Storing data

[nexirius]

Dear all


I am new here and I checked out several tutorials to get in touch with the
Objective C.

Now I'm wondering how you prefer to store your data. Many people were
talking about SQLite, but until now I was "scared" to start with that as
I have not that much experience with Objective C.


Some hours ago I found this code example:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults]; 
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"]; 
[prefs synchronize];

I have successfully tested it and I wondered how this stuff is stored? When
I tried it on my iPod it seemed that this data is stored until you delete your
application. Is that really true?

When do people use this method? I guess if you have more data, you should
use SQLite?


Thanks for your answers! I'm looking forward to reading them!

[chrysb]

I use NSUserDefaults for storing simple data, such as preferences, or simple states.

For more complex things, like objects and arrays, I use local file storage. I created a key-based caching class that automatically saves things to disk and loads them again when the application starts. It's very convenient.

SQLite makes sense if you have a *lot* of data that you're storing on the phone and you need a relational database.

[Son of a Beach]

User defaults are easy and convenient. A great way for storing smaller amounts of data.

For larger amounts of data, you should look into CoreData (which usually uses SQLite internally, but abstracts you from it). It's essentially a persistence layer for objects.

Some object types (eg, NSArray, NSString, NSData) also have convenience methods for reading/writing themselves in their entirely to/from disk. NSKeyedArchiver can help with more complex/custom object classes too. Sometimes this can be useful, but CoreData or User defaults are usually better.

[nexirius]

Wow thanks! Cool, I guess I understood it correctly thing then.

And these NSUserDefaults are stored as long as I delete, overwrite it or the
app is deleted? And I could also save Arrays to it?