将SQL Server rowversion转换为long或ulong? [英] converting sql server rowversion to long or ulong?

问题描述

rowversion(时间戳)数据类型的正确类型是什么?

What is the proper type for the rowversion (timestamp) data type?

我知道它是8个字节，但是我无法在MSDN中找到一个链接，该链接表明它是带符号的还是无符号的长.

I know it is 8 bytes but i cannot find a link in MSDN which tell if it is a signed or unsigned long.

我应该使用哪个代码，这有关系吗?

which code should I use, does it even matter?

byte[] SqlTimeStamp;

long longConversion;
longConversion = BitConverter.ToInt64(SqlTimeStamp,0);
TimeStamp = BitConverter.GetBytes(longConversion);

ulong ulongConversion;
ulongConversion = BitConverter.ToUInt64(SqlTimeStamp,0);
TimeStamp = BitConverter.GetBytes(ulongConversion);

推荐答案

简短的回答:没关系，但是我选择UInt64.

Short answer: it doesn't matter but I'd choose UInt64.

详细信息:从语义上讲，它等效于binary(8)，因此严格来说，它既不是UInt64也不是Int64，而只是一个字节块(因此应该对其进行管理).那就是说我选择UInt64是因为它是一个递增数字来保存行版本，然后(从逻辑的角度来看)0xFFFFFFFFFFFFFFFF应该大于0，而对于Int64(因为将64位设置为1会给出-1，并且小于0).

Details: semantically it's equivalent to binary(8) so, strictly speaking, it's neither UInt64 nor Int64 but just a chunk of bytes (and in that way it should be managed). That said I'd choose UInt64 because it's an incrementing number to hold row version then (from a logic point of view) 0xFFFFFFFFFFFFFFFF should be greater than 0 and it's not true for Int64 (because 64 bits set to 1 give -1 and it's less than 0).

编辑:请注意，由于仅在SQL Server设计者圈子中才知道的原因，ROWVERSION是大尾数法(而-显然-bigint不是)，那么您首先需要反向字节，请参见此答案以实现良好的实现.

Edit: note that, for reasons known only in the innest SQL Server designers circle, ROWVERSION is big-endian (while - obviously - bigint is not) then you first need to reverse bytes, see this answer for a nice implementation.

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