如何把数组做为一个字段存入存入数据库

插入的时候先把数组转化为字符串，取出的时候再把字符串转化为数组

将string字符串转换为array数组

NSString *a = [[NSString alloc] initWithString : @"冬瓜，西瓜，火龙果，大头，小狗" ];

    NSArray *b = [a componentsSeparatedByString:@"，"];

    NSString *a3 = [b objectAtIndex:2];

    NSLog(@"   b的第三个东东是： %@", a3);

    [a release];

 NSArray  *array = [Str componentsSeparatedByString:@","];

＝＝反向方法

将array数组转换为string字符串

NSArray *array = ［NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];
    NSString *string = [array componentsJoinedByString:@","];
    NSLog(@"string:%@",string);