NSUserDefaults vs sqlite3

Question

I have a small iPhone app that stores a list of objects. The user can add and remove objects, but this list will remain fairly small (most users would have 10-30 objects). NSUserDefaults seems much easier to work with, but will sqlite3 be faster? With only 30 "records" will there be any noticeable difference?

Gyro

Core Data is the best option for iPhone OS now. – Gyro

Answer 1

NSUserDefaults is for user preferences, usually basic objects like NSString or NSNumber. Sqlite, serializing a collection of objects in a property list, or Core Data are all valid options for storing user data such as model objects you created.

You're not going to see a speed difference, but it's still best to pick the correct mechanism for what you're doing. If it's just preferences then use NSUserDefaults, otherwise I would serialize your objects to a plist. If you're new to Cocoa I would avoid Core Data and even sqlite at first, to give yourself a chance to learn the basics first.

Splat

I am new to Cocoa but not database systems. Most of the tutorials I have read make it seem like there is a lot of overhead in sqlite statements. It seems like the standard is to read all of the data at launch and cache changes until the app is terminated. – Gyro

I am just going to continue using sqlite3. It seems like the more logical solution for this type of data. – Gyro

Answer 2

Try with NSCoding protocol. Declare your class to implement NSCoding protocol:

@interface Person : NSObject <NSCoding>

Previous line promises to implement the following methods:

-(id)initWithCoder:(NSCoder *)coder;
-(void)encodeWithCoder:(NSCoder *)coder;

Your methods should look something like:

-(void)encodeWithCoder:(NSCoder *)coder {
  [super encodeWithCoder:coder];
  [coder encodeObject:firstName forKey:@"firstName"];
  [coder encodeObject:lastName forKey:@"lastName"];
}

-(id)initWithCoder:(NSCoder *)coder {
  [super init];
  firstName = [[coder decodeObjectForKey:@"firstName"] retain];
  lastName = [[coder decodeObjectForKey:@"lastName"] retain];
  return self;
}

Redeeming

I will have to look into this for my next project. – Gyro

This is the answer for "How can I save objects to NSUserDefaults" and not discussing the benefits of the different possibilities. – Pneumonoultramicroscopicsilicovolcanoconiosis