Example Analysis of splitting Entity Framework Table into multiple entities

Editor to share with you the Entity Framework table is divided into multiple entities of the example analysis, I hope you will learn something after reading this article, let's discuss it together!

Concept

Table split: a table is split into multiple entities, such as the Photograph table, which can be split into Photograph and PhotographFullImage tables.

1. Photograph entity structure: using System;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using System.ComponentModel.DataAnnotations.Schema;using System.Linq;using System.Text;using System.Threading.Tasks Namespace CodeFirstTableSplit.Model {/ thumbnail class / public class Photograph {/ set PhotoId is the primary key auto-growth / [Key] [DatabaseGenerated (System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)] public int PhotoId {get; set;} public string Title {get; set } / thumbnail / public byte [] ThumbnailBite {get; set;} / reference PhotographFullImage / [ForeignKey ("PhotoId")] public virtual PhotographFullImage PhotographFullImage {get; set;}} 2 through navigation attributes, PhotographFullImage entity structure: using System;using System.Collections.Generic Using System.ComponentModel.DataAnnotations;using System.ComponentModel.DataAnnotations.Schema;using System.Linq;using System.Text;using System.Threading.Tasks;namespace CodeFirstTableSplit.Model {public class PhotographFullImage {[Key] public int PhotoId {get; set;} / High Resolution / public byte [] HighResolutionBits {get; set } / PhotographFullImage references Photograph / / [ForeignKey ("PhotoId")] public virtual Photograph Photograph {get; set;}} 3 through navigation attributes, and creates a data context object subclass: using CodeFirstTableSplit.Model;using System;using System.Collections.Generic;using System.Data.Entity;using System.Linq;using System.Text;using System.Threading.Tasks Namespace CodeFirstTableSplit.DatabaseContext {public class EFDbContext: DbContext {public EFDbContext (): base ("name=Default") {} public DbSet Photographs {get; set;} public DbSet PhotographFullImages {get; set;} protected override void OnModelCreating (DbModelBuilder modelBuilder) {/ / set principal modelBuilder.Entity (). HasRequired (p = > p.PhotographFullImage) .WithRequiredPrincipal (t = > t.Photograph) / / generate the same table: set two entities to have the same table name modelBuilder.Entity (). ToTable ("Photograph"); modelBuilder.Entity (). ToTable ("Photograph"); base.OnModelCreating (modelBuilder);}} 4. Generate the database structure using data migration to view the generated structure:

5. Write data using CodeFirstTableSplit.DatabaseContext;using CodeFirstTableSplit.Model;using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace CodeFirstTableSplit {class Program {static void Main (string [] args) {using (var context = new EFDbContext ()) {/ / write data byte [] thumbBits = new byte [100] Byte [] fullBits = new byte [2000]; var photo = new Photograph () {Title = "Li Si", ThumbnailBite = thumbBits}; var fullImage = new PhotographFullImage () {HighResolutionBits = fullBits}; photo.PhotographFullImage = fullImage; context.Photographs.Add (photo); / / Save context.SaveChanges () } Console.WriteLine ("created successfully"); Console.ReadKey ();} 6. Query data

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