Обеспечение максимального количества связей в одновременных запросах ⇐ C#

[Anonymous]

I have these entities in my business:

class Team { public int Id { get; set; } public string Name { get; set; } public List Members { get; set; } } class Member { public int TeamId { get; set; } public int UserId { get; set; } } The business rule is that a team cannot have more than 10 members.

So you can add a constraint in your controller or handler like this: AddTeamMemberHandler.cs:

var team = dbContext.Teams .Include(x => x.Members) .FirstOrDefault(x => x.Id == 123); if (team.Members.Count >= 10) throw new Exception("Cannot add more members"); However, when you have multiple users trying to add users at the same time, and the current number of members in the team is 9, all of the request will pass the validation. This can lead to the number of members in the team exceeding 10.

I think it is possible to add a custom SQL constraint in the EF model configuration like this:

modelBuilder.Entity() .HasCheckConstraint("Team_MaxMembers", $"COUNT(\"Members\")

Источник: https://stackoverflow.com/questions/769 ... t-requests