Question

I m 开发一个具有某些潜在较大数据表的蚊帐应用。我愿知道,确定首要钥匙的最佳方式是什么。我知道以前曾提出过这个问题,但由于情况特殊,我认为这个问题是有效的。

在2008年服务器数据库中使用实体框架4。

考虑到以下因素,界定主要关键的可能性是什么:

There is a real possibility that over time the number of records will exceed the 32 bit boundary, so an auto-increment integer will not be possible.
There is no possibility to define a primary key on a combination of other columns in the table.
For data synchronization reasons, an application-generated id would be preferable over a database-generated id. Also, in EF it would mean an extra roundtrip to the database to retrieve the newly generated id.
For insert performance, a sequential key would be preferable.
I consider the space requirements for a (sequential) guid a downside.
For string id s, case insensitivity would be preferable.

我迄今亲眼看到的是一种习俗算法,它产生一个白天部分和随机部分,变成了六dec代代表。这使我留下的体力略低于指导。我仍可以将其改为64,但这将涉及项目6。

感谢您的建议。

Answer 1

您可考虑将贵钥匙储存为BIGINT(8 byte integer)。

BIGINT公司与INT公司完全一样,可以以同样的方式在自动加固的身份栏中使用。

Answer 2

这里有两点想法。

Consider the binary data type of size 5 or 6 bytes.
Do not overlook the benefits of partitioned tables especially for large tables.
Keep the remaining columns as small as possible. Sometimes the star schema can help with this.

不幸的是,你不能把双元数据识别栏列。但您可使用<代码>max(Id)+1插入战略。我不是这样熟悉的。 NET是实体框架,但应当有办法在同一次访问中检索钥匙。我过去看到了文件,解释如何绘制实体的地图,以储存程序,并从中提取钥匙,但我没有任何具体内容。

Answer 3

我将在您的案例中使用一个顺序式的《国际统一准则》。

it is a surrogate key
it is application generated, so no need to retrieve a database generated id after inserts
it is sequential and will work well with clustered indexes
if you may overflow 32 bit keys you will probably have to use 64 bit keys anyway (besides you manage to create and use 48 bit keys or something like that) - then 128 bit GUIDs only require twice the space
string surrogate keys are somewhat unnatural to me and I can see no benifit over GUID keys