将NSDate插入CoreData时出错 [英] Error when inserting NSDate to CoreData

问题描述

    NSDateFormatter *dt = [[NSDateFormatter alloc] init];
    [dt setDateFormat:@"dd-MM-yyyy"];
    NSDate *bdate = [dt dateFromString:@"02-02-2013"];
    [nouContacte setValue:bdate forKey:@"birthday"];

我不明白为什么该代码不起作用。它会插入9个不同的数字，例如318366000。
我可以插入字符串，布尔值，数字，但我不能输入日期。

I don't understand why that code doesn't work. It inserts 9 different digits like 318366000. I can insert strings, "booleans", numbers, but i can't with date.

coredata中的生日字段是日期类型。

birthday field in coredata is date type.

有什么想法吗？

推荐答案

日期属性，Core Data在SQLite文件中存储自2001年1月1日以来，格林尼治标准时间的秒数，即

For a "Date" attribute, Core Data stores the "number of seconds since 1 January 2001, GMT" in the SQLite file, i.e. what you get with

[bdate timeIntervalSinceReferenceDate]

例如， 2011-02-02 19:00:00 +0000 存储为数字 318366000 。

但是这是一个实现细节，您不必担心。
从SQLite文件中读取对象时，将数字转换回 NSDate 。

But that is an implementation detail and you should not worry about it. When reading objects from the SQLite file, the number is converted back do an NSDate.

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