Disable cascade delete on EF Core 2 globally - entity-framework

Question

I need to know about ways of disabling cascade delete in EF Core 2 globally. Any help is appricated.
In EF 6.x we used following code to disable cascade delete on both OneToMany and ManyToMany realtions:
builder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
builder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();

Answer 1

Unfortunately EF Core currently (latest at this time v2.0) does not expose a good way to control the conventions globally.
The default EF Core 2.0 convention is to use DeleteBehavior.Cascade for required and DeleteBehavior.ClientSetNull for optional relationships. What I can suggest as workaround is a typical metadata model loop at the end of the OnModelCreating override. In this case, locating all the already discovered relationships and modifying them accordingly:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
// ...
var cascadeFKs = modelBuilder.Model.GetEntityTypes()
.SelectMany(t => t.GetForeignKeys())
.Where(fk => !fk.IsOwnership && fk.DeleteBehavior == DeleteBehavior.Cascade);
foreach (var fk in cascadeFKs)
fk.DeleteBehavior = DeleteBehavior.Restrict;
base.OnModelCreating(modelBuilder);
}

Answer 2

constraints: table =>
{
table.PrimaryKey("PK_ComandaPlato", x => x.ComandaPlatoId);
table.ForeignKey(
name: "FK_ComandaPlato_Comanda_ComandaId",
column: x => x.ComandaId,
principalTable: "Comanda",
principalColumn: "ComandaId",
onDelete: ReferentialAction.Cascade);//default: cascade on
table.ForeignKey(
name: "FK_ComandaPlato_Plato_PlatoId",
column: x => x.PlatoId,
principalTable: "Plato",
principalColumn: "PlatoId",
onDelete: ReferentialAction.NoAction);//turn off cascade,"by hand"
});
//comments: modifing the auto-generated migration, "harcode by hand" this attibute, as view bellow: change "Cascade" to "NoAction" (as view 1st and 2st examples)

Answer 3

May be It helps:
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
ChangeTracker.CascadeDeleteTiming = ChangeTracking.CascadeTiming.Never;
ChangeTracker.DeleteOrphansTiming = ChangeTracking.CascadeTiming.Never;
}