分配使用PRIMARY KEY约束的字符串>>违反作用

Question

我有以下代码：

  var roleEditionCNT = new Role { ApplicationName = "TTT", RoleName = "EDITION_CNT" }; 
      var roleEditionKCD = new Role { ApplicationName = "TTT", RoleName = "EDITION_KCD" }; 
      var roleEditionInterne = new Role { ApplicationName = "TTT", RoleName = "EDITION_INTERNE" }; 
      var roleConsultationInterne = new Role { ApplicationName = "TTT", RoleName = "CONSULTATION_INTERNE" }; 
      var roleConsultationExterne = new Role { ApplicationName = "TTT", RoleName = "CONSULTATION_EXTERNE" }; 
      var roleAdministrator = new Role { ApplicationName = "TTT", RoleName = "ADMINISTRATOR" }; 

      new List<Role> 
       { 
        roleEditionCNT, 
        roleEditionKCD, 
        roleEditionInterne, 
        roleConsultationInterne, 
        roleConsultationExterne, 
        roleAdministrator 
       }.ForEach(b => context.Roles.AddOrUpdate(m => m.RoleName, b)); 

然后，我可以这样做：

var myUser = new User 
     { 
     Company = "DELTOY", 
     FirstName = "BRYAN", 
     LastName = "KENETH", 
     Roles = new List<Role> { roleEditionCNT } 
     }; 

现在我想修改的方法我分配这样的角色：

var myUser = new User 
     { 
     Company = "DELTOY", 
     FirstName = "BRYAN", 
     LastName = "KENETH", 
     Roles = new List<Role> { new Role { ApplicationName = "TTT", RoleName = "EDITION_CNT" } } 
     }; 

此代码编译成功，但在运行时我得到了错误：

Violation of PRIMARY KEY constraint 'PK_Roles'. Cannot insert duplicate key in object 'dbo.Roles'

通过简单地修改上面的代码，似乎系统正试图添加一个新的记录到表角色。我怎样才能简单地分配角色但不使用变量。我更喜欢用一个字符串给角色名称。

有什么想法？

Answer 1

在第二个示例中，您尝试添加具有新角色的用户，而不是将其分配给现有角色。您尝试添加的角色已存在于角色表中。

您可以将Role对象获取到类似的变量中。

var role = context.First(p => p.RoleName == "EDITION_CNT"); 

然后将其分配给新的用户。

var myUser = new User 
     { 
     Company = "DELTOY", 
     FirstName = "BRYAN", 
     LastName = "KENETH", 
     Roles = new List<Role> { role } 
     };