sql - ASP MVC Delete only the relation between 2 tables (many-to-many relation) -

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using asp mvc active record.

ive got 2 tables records related , aren't. relation defined user. 1 table has projects, other has devices. projects can created , deleted, devices cannot. when user deletes project, relations between project , devices should removed, devices should remain.

how do this?

my delete action looks this:

public actionresult delete(int id, formcollection collection)   {      if (!project.exists(id)) return redirecttoaction("index/1", "error");       try      {         project project = project.find(id);           if (project.user.id != sessionvariables.authenticateduser.id) return redirecttoaction("index/1", "error");          project.deleteandflush();          return redirecttoaction("index", "project");      }      catch(exception e)      {         return redirecttoaction("index", "error");      }   }

so if understand correctly, when project deleted projects table want delete entries in projectdevice mapping table? (i assume using many many relationship 1 of questions).

if that's case, recommend use database trigger, rather try , manually in code. can create trigger removes rows specific project in mapping table, when project deleted project table. if you're using ms sql like:

create trigger trig_deleteprojectdevice on projecttable delete declare @projectid int select @projectid = (select projectid deleted) delete projectdevicemappingtable projectid = @projectid

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