Allow specifying different column names per table in TPT, TPC or entity splitting

[AndriySvyryd]

E.g. int Id could be mapped to int Id in People and to string CustomerId in Customers

TPC:

    modelBuilder.Entity<Person>().ToTable("People")
        .InheritPropertyMapping(false);  
    modelBuilder.Entity<Customer>().ToTable("Customers", t =>
        {
            t.Property(c => c.Id).HasColumnName("CustomerId");
        });

Entity splitting:

    modelBuilder.Entity<Customer>(cb =>
    {
        cb.ToTable("Customers");
        cb.SplitToTable("CustomerDetails", t =>
        {
            t.Property(c => c.Id).HasColumnName("CustomerId");
        })
    };

Also allow to map a base property to the derived table in TPT

TPT:

    modelBuilder.Entity<Person>().ToTable("People");  
    modelBuilder.Entity<Customer>().ToTable("Customers", t =>
        {
            t.Property(c => c.Id).HasColumnName("CustomerId");
        });

Related: #17270 (comment)

[smitpatel]

A possible side-effect in query, that if you are writing query like context.People.Where(e => e.Id == 5) then translating that could be complicated, since now you have to apply the predicate to both the tables separately before generating Union. Which could easily go downhill when the Id start being used in complex query operators like join conditions etc.

[smitpatel]

Just different column names or just different but database implicit convertible column types should be ok.

[AndriySvyryd]

Test for SQL Server FKs being uniquified correctly:

            [ConditionalFact]
            public virtual void TPT_inherited_FK_is_uniquified()
            {
                var modelBuilder = CreateModelBuilder();
                modelBuilder.Entity<BigMak>()
                    .Ignore(b => b.Bun)
                    .Ignore(b => b.Pickles);
                modelBuilder.Entity<Ingredient>(b =>
                {
                    b.ToTable("Ingredients");
                    b.HasOne(i => i.BigMak).WithOne().HasForeignKey<Ingredient>("BigMakId")
                        .HasConstraintName("FK_Buns_Ingredients_Id");
                });
                modelBuilder.Entity<Bun>(b =>
                {
                    b.ToTable("Buns");
                });
                modelBuilder.Entity<Pickle>(b =>
                {
                    b.ToTable("Pickles");
                });

                var model = modelBuilder.FinalizeModel();

                var principalType = model.FindEntityType(typeof(BigMak));
                Assert.Empty(principalType.GetForeignKeys());
                Assert.Empty(principalType.GetIndexes());

                var ingredientType = model.FindEntityType(typeof(Ingredient));

                var bunType = model.FindEntityType(typeof(Bun));
                var bunFk = bunType.GetDeclaredForeignKeys().Single();
                Assert.True(bunFk.IsBaseLinking());
                Assert.Equal("FK_Buns_Ingredients_Id", bunFk.GetConstraintName());
                Assert.Equal("FK_Buns_Ingredients_Id1", bunFk.GetConstraintName(
                    StoreObjectIdentifier.Create(bunType, StoreObjectType.Table).Value,
                    StoreObjectIdentifier.Create(ingredientType, StoreObjectType.Table).Value));
                Assert.Equal(bunType.GetForeignKeys().Count() - 1, bunType.GetIndexes().Count());
                Assert.True(bunFk.DeclaringEntityType.FindIndex(bunFk.Properties).IsUnique);

                var pickleType = model.FindEntityType(typeof(Pickle));
                var pickleFk = pickleType.GetDeclaredForeignKeys().Single();
                Assert.True(pickleFk.IsBaseLinking());
                Assert.Equal("FK_Pickle_Ingredients_Id", pickleFk.GetConstraintName());
                Assert.Equal("FK_Pickle_Ingredients_Id", pickleFk.GetConstraintName(
                    StoreObjectIdentifier.Create(pickleType, StoreObjectType.Table).Value,
                    StoreObjectIdentifier.Create(bunType, StoreObjectType.Table).Value));
                Assert.Equal(pickleType.GetForeignKeys().Count() - 1, pickleType.GetIndexes().Count());
                Assert.True(pickleFk.DeclaringEntityType.FindIndex(pickleFk.Properties).IsUnique);
            }