Remove all entities not in a range using EF Core?

Question

Say I have a database with these entries in the people table:

id | companyId | name 
1  | 9         | Kevin
2  | 9         | Mike
3  | 9         | John

I then get this put request to update the entities:

[
    {"id": 1, "name": "Kevin"},
    {"id": 2, "name": "Michael"},
    {"id": 0, "name": "Joe"}
]

So, I need to Update id 2, remove id 3, and add the new entity. I know _context.People.UpdateRange(entities) will update the existing entities and add the new ones, but I also need to remove id 3. Basically, the content of the json request should be the entirety of the people table where companyId = 9 . I know I can do this:

var currentPeople = _context.People
   .AsNoTracking()
   .Where(e => e.companyId == request.companyId)
   .ToListAsync();

var requestEntities = request
   .Select(m => new PersonEntity(r))
   .ToList();

var peopleToRemove = requestEntities
   .Where(oldEntity => requestEntities.All(e => e.Id != oldEntity.Id))
   .ToList();

using (var transaction = _context.Database.BeginTransaction())
{
    _context.People.RemoveRange(peopleToRemove);
    _context.People.UpdateRange(requestEntities);
    await _context.SaveChangesAsync();
    transaction.Commit();
}

But that's super clunky. Does EF Core offer a better solution? Thanks!

Answer 1

You can do as follows:

var existingPeopleList = _context.People.AsNoTracking()
                                 .Where(e => e.companyId == request.companyId) 
                                 .ToListAsync();

var requestEntities = request.Select(r => new PersonEntity(r)).ToList();

var requestedPeopleList = requestEntities.Select(re => new People()
                          {
                              Id = re.Id,
                              CompanyId = 9,
                              Name = re.Name
                          }).ToList();



var peopleToBeRemoved = existingPeopleList.Where(ep => requestedPeopleList.All(rp => rp.Id != ep.Id)).ToList();

var peopleToBeAdded = requestedPeopleList.Where(rp => existingPeopleList.All(ep => ep.Id != rp.Id)).ToList();

var peopleToBeUpdated = requestedPeopleList.Where(rp => existingPeopleList.Any(ep => ep.Id == rp.Id)).ToList();

_context.People.RemoveRange(peopleToBeRemoved);
_context.People.AddRange(peopleToBeAdded);
_context.People.UpdateRange(peopleToBeUpdated);
await _context.SaveChangesAsync();