iphone开发中的数据存储：初

iphone上的数据存储有四种模式：

Property lists       属性列表　　
Object archives (or archiving) 　　对象归档　　
SQLite3 (iOS’s embedded relational database)　　

Core Data (Apple’s provided persistence tool) 

存储中经常需要提取两个相关的目录路径：Documents和tmp

Getting the Documents Directory ：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *filename = [documentsDirectory stringByAppendingPathComponent:@"theFile.txt"];

Getting the tmp Directory ：

NSString *tempPath = NSTemporaryDirectory();

NSString *tempFile = [tempPath stringByAppendingPathComponent:@"tempFile.txt"];

文件存储分为单文件存储和多文件存储（Single-File Persistence 、Multiple-File Persistence ）