Many to many mapping and insert, update operation

[Peenty]

Hello, 
I have many to many mapping on basis tables:

Roles
Id int, PK
Name varchar(50), not null

Privileges
Id int, PK
Name varchar(50), not null

RolePrivileges
RoleId int, PK, FK to Roles.Id
PrivilegeId int, PK, FK to Privileges.Id

I have existing privileges (in table Privileges) and I'd like to insert a new Role with selected privileges. 
I try someting like this:

Role role = new Role();
role.Name = "Role ABC";
role.Privileges.Add(new Privilege { Id = 1, Name = "Privilege 1" });
role.Privileges.Add(new Privilege { Id = 3, Name = "Privilege 3" });
dbContext.AddRole(role);

After this I get error Telerik.OpenAccess.Exceptions.DuplicateKeyException because it tries to insert 

new privileges (to Privileges table) instead of to insert new row to RolePrivileges table.


Regards

k

[Damyan Bogoev]

Hello Krzysztof,

You should slightly modify this code snippet in the following way:

Role role = new Role();
role.Name = "Role ABC";
Privilege firstPrivilege = dbContext.Privileges.FirstOrDefault(x => x.Id == 1);
Privilege secondPrivilege = dbContext.Privileges.FirstOrDefault(x => x.Id == 3);
role.Privileges.Add(firstPrivilege);
role.Privileges.Add(secondPrivilege);

dbContext.AddRole(role);

Hope that helps.

Regards,
Damyan Bogoev
the Telerik team

[KFS]

How can that managed if the select and insert operation managed by different DB context ?

Privilege firstPrivilege =  dbContext1.CreateDetachedCopy( dbContext1.Privileges.FirstOrDefault(x => x.Id ==  1));

Role role = new Role();

role.Name = "Role ABC";
role.Privileges.Add(firstPrivilege);

dbContext2.AddRole(role);

This cause create new privilege and insert the new privilege Id in table RolePrivileges.

Thanks,

[Boris Georgiev]

Hi,

I was not able to reproduce this behavior. The observed and default behavior in this scenario is that only new role will be created in the database and one record will be added in the Join table between the id of the new role and the id of the detached privilege. To achieve this behavior you should add the new created role to the navigation property of the detached privilege and Attach the role to the context, for that you should use AttachCopy method instead Add method.

For your convenience I attached a sample which demonstrates the workflow.

I hope that helps.

Regards,
Boris Georgiev
Telerik by Progress