DbContext类有一个OnModelCreating方法，可以在这里配置模型，该方法接收一个类型为DbModelBuilder的建造者，本文介绍的为Data Anotation的等价方法，这些代码是自解释的。

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            // Configure Code First to ignore PluralizingTableName convention
            // If you keep this convention then the generated tables will have pluralized names.
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();

            // Default Schema (EF6 onwards)
            modelBuilder.HasDefaultSchema("sales");

            // Configuring a Primary Key [Key]
            modelBuilder.Entity<OfficeAssignment>().HasKey(t => t.InstructorID);

            // Configuring a Composite Primary Key
            modelBuilder.Entity<Passport>().HasKey(t => new { t.PassportNumber, t.IssuingCountry });

            // Switching off Identity for Numeric Primary Keys
            modelBuilder.Entity<Passport>().Property(t => t.PassportNumber).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

            // Specifying the Maximum Length on a Property
            modelBuilder.Entity<Passport>().Property(t => t.IssuingCountry).HasMaxLength(50);

            // Configuring the Property to be Required
            // (NOT NULL) [Required]
            modelBuilder.Entity<Passport>().Property(t => t.Issued).IsRequired();

            // Specifying Not to Map a CLR Property to a Column in the Database
            // [NotMapped]
            modelBuilder.Entity<Blog>().Ignore(t => t.BlogCode);

            // Mapping a CLR Property to a Specific Column in the Database
            // [Column("BlogTitle")]
            modelBuilder.Entity<Blog>().Property(t => t.Title).HasColumnName("BlogTitle");

            // Configuring whether a String Property Supports Unicode Content
            // (varchar not nvarchar)
            modelBuilder.Entity<Blog>().Property(t => t.Title).IsUnicode(false);

            // Configuring the Data Type of a Database Column [Column(TypeName = "varchar")]
            modelBuilder.Entity<Department>().Property(p => p.Name).HasColumnType("varchar");

            // Mapping an Entity Type to a Specific Table in the Database
            modelBuilder.Entity<Department>().ToTable("t_Department");

            // 第二个参数是SCHEMA
            modelBuilder.Entity<Department>().ToTable("t_Department", "school");

            // Specifying That a Class Is a Complex Type
            modelBuilder.ComplexType<Details>();

            // Specifying Not to Map a CLR Entity Type to a Table in the Database
            // [NotMapped]
            modelBuilder.Ignore<OnlineCourse>();

            // Configuring Properties on a Complex Type
            // Method 1
            modelBuilder.ComplexType<Details>().Property(t => t.Location).HasMaxLength(20);
            // Method 2
            modelBuilder.Entity<OnsiteCourse>().Property(t => t.Details.Location).HasMaxLength(20);

            // Configuring a Property to Be Used as an Optimistic Concurrency Token
            modelBuilder.Entity<OfficeAssignment>().Property(t => t.Timestamp).IsConcurrencyToken();

            // Configuring the property to be a row version in the database
            modelBuilder.Entity<OfficeAssignment>().Property(t => t.Timestamp).IsRowVersion();
        }