The conversion from datetime2 data type to datetime data type generates a value out of the range

Background:
If you use entityframe to write a sqlserver field whose type is datetime and the default value is getdate (), an exception is thrown,
Exception information: the conversion from the datetime2 data type to the datetime data type generates a value out of the range

Cause:
1. datetime returned in C # is inconsistent with datetime returned in SQL Server. The range in C # is wide.
2. the attribute of the corresponding table field is not set in the edmx file.

Solution:
1. For cause 1, set the database field type to datetime2.
2. Corresponding to cause 2: Find the corresponding field in the edmx file and set the storegeneratedpattern attribute to identity.