How to Update database table row when the foreign key has the same value ASP.NET mvc - entity-framework

Question

I have a application where stores can complete a questionnaire. within this application i have two tables db.StoreAud(pk:AuditId) which contains all the stores information, and db.storequests(pk:ReviewId) which holds the all questions information.
AuditId is a foreign key in db.storequests table. Now here is the issue if a store complete the questionnaire the data saves perfectly in the database, however is the same store does the questionnaire again the db.storequests creates a new row in the database with a new primary key value instead of updating the previous row. Question is how can i update the previous row if the same store does the same questionnaire again. hope this made since.
db.StoreAUD
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
[Column(Order = 1)]
public int AuditId { get; set; }
public string Date { get; set; }
public int StoreNumber { get; set; }
public string StoreName { get; set; }
db.storequests
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public int ReviewId { get; set; }
public int AuditId { get; set; }
public int QuestionOne { get; set; }
public string QuestionTwo { get; set; }
public string QuestionThree { get; set; }
public string QuestionFour { get; set; }
controller
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create(StoreQuestions storequestions)
{
if (ModelState.IsValid)
{
StoreAudit findingAudit = db.StoreAudit.Find(storequestions.AuditId); // grabbing the id from th store audit table
findingAudit.ReadOnlyTickBox = true;
db.StoreQuestions.Add(storequestions);
db.SaveChanges();
return RedirectToAction("Details", "Audit", new { id = storequestions.AuditId });
}
return View(storequestions);
}

Answer 1

I would seperate your update logic into a new Update action, following the Single Responsibility Principle:
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Update(StoreQuestions storequestions)
{
if (ModelState.IsValid)
{
StoreAudit findingAudit = db.StoreAudit.Find(storequestions.AuditId);
findingAudit.ReadOnlyTickBox = true;
// update objects here
db.SaveChanges();
return RedirectToAction("Details", "Audit", new { id = storequestions.AuditId });
}
return View(storequestions);
}
}