Entity Framework - 让EDM支持低版本SQL

问题：

项目使用的.edmx文件是基于SQL 2008的数据库 （没有用的SQL2008的新特性），客户后来要求支持SQL2005，测试中发现数据存取时遇到一个异常：

the version of SQL Server in use does not support datatype 'datetime2'

datetime2是SQL2008引入的一个新类型
，异常由此而来。


解决办法：


使用xml编辑器打开.edmx文件将 其中的ProviderManifestToken
=
"2008"


修改PoviderManifestToken
=
"2005" 即可





more - 关于Known Issues:

The Entity Framework targets the Transact-SQL query based on the SQL Server version that is specified in the ProviderManifestToken attribute of the Schema element in the storage model file (SSDL). This version might differ from the version of the actual SQL Server you are connected to. For example, if you are using SQL Server 2005, but your ProviderManifestToken attribute is set to 2008, the generated Transact-SQL query might not execute on the server. For example, a query that uses the new date time types that were introduced in SQL Server 2008 will not execute on earlier versions of the SQL Server. If you are using SQL Server 2005, but your ProviderManifestToken attribute is set to 2000, the generated Transact-SQL query might be less optimized, or you might get an exception that says that the query is not supported. For more information, see the CROSS and OUTER APPLY Operators section, earlier in this topic.

Certain database behaviors depend on the compatibility level set to the database. If your ProviderManifestToken attribute is set to 2005 and your SQL Server version is 2005, but the compatibility level of a database is set to "80" (SQL Server 2000), the generated Transact-SQL will be targeting SQL Server 2005, but might not execute as expected due to the compatibility level setting. For example, you might lose ordering information if a column name in the ORDER BY list matches a column name in the selector.

http://msdn.microsoft.com/en-us/library/bb896273.aspx