How to add/update/delete n-n tables?

I've this tables on my SQL Server Database:

On my ASP.NET MVC app I manage the Clinics for each Medical. So let say Medical ID 1 can have N associated Clinics, such as Clinic ID 5, 8, 10.

ASP.NET MVC

Clinics

Medical

Medical ID 1

Clinic ID 5, 8, 10

Here's my attempt in the Controller's Action:

Controller's Action

if (ModelState.IsValid)

Medicals medical = mapper.Map<MedicalViewModel, Medicals>(medicalViewModel);

// medical
ctx.Entry(medical).State = medical.ID == 0 ? EntityState.Added : EntityState.Modified;

ctx.SaveChanges();

// relationships medical/clinics
foreach (var clinic in medicalViewModel.ClinicsList)

Clinics clinics = new Clinics() ID = clinic.ID ;

// delete
if (!clinic.IsChecked)

medical.Clinics.Remove(clinics);

// add/update
else

medical.Clinics.Add(clinics);



ctx.SaveChanges();



But its not able to either delete or add/update.

Where am I wrong? I don't have the table ClinicsMedicals generated by Entity Framework, so I guess I need to access by Medicals.

ClinicsMedicals

Entity Framework

Medicals

1 Answer
1

Here is what I think you need to do:

if (ModelState.IsValid)

Medicals medicalEntity;
if(medicalViewModel.ID == 0)

medicalEntity = ctx.Set<Medicals>().Add(new Medicals());

else

// retrieve existing entity
medicalEntity = ctx.Set<Medicals>().Find(medicalViewModel.ID);

if(medicalEntity == null)
// log and throw exception may be?


// apply new changes to existing entity
medicalEntity = mapper.Map<MedicalViewModel, Medicals>(medicalViewModel, medicalEntity);

// relationships medical/clinics
foreach (var clinicViewModel in medicalViewModel.ClinicsList)

var clinicEntity = medicalEntity.Clinics.FirstOrDefault(x => x.ID == clinicViewModel.ID);

// delete
if (!clinicViewModel.IsChecked)

medicalEntity.Clinics.Remove(clinicEntity);

else

if(clinicEntity == null) // add

medicalEntity.Clinics.Add(ctx.Set<Clinics>().Find(clinicViewModel.ID));

else

// update




ctx.SaveChanges();



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