简介： 逆向操作DB到Code First Classes

The Entity Framework team blogged about the EF Power Tools CTP1 today. One of the intriguing features is the ability to reverse engineer an existing database into a set of code first classes.

I put it to a *very* quick test since it’s way past my bedtime.


After installing the tool and creating a new class library project, I reverse engineered the following tiny simple database:





The tool created a bunch of classes grouped into an Entities folder (from tables and views in my db), a set of fluent api mappings grouped into a Mapping folder and a context class. It also added the EntityFramework.dll for EF 4.1 and System.Data.Entity to the project.





A quick look at one of the Customer.cs class:

using System;
using System.Collections.Generic;

namespace TestEFPowerToolsCTP1.Entities
{
public class Customer
{
public Customer()
{
this.Orders = new List<Order>();
}

public int CustomerID { get; set; }
public string Title { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string LastName { get; set; }
public string Suffix { get; set; }
public string CompanyName { get; set; }
public string SalesPerson { get; set; }
public string EmailAddress { get; set; }
public string Phone { get; set; }
public System.DateTime ModifiedDate { get; set; }
public byte[] TimeStamp { get; set; }
public virtual ICollection<Order> Orders { get; set; }
}
}

The Customer mapping file:

using System;
using System.Data.Entity.ModelConfiguration;
using System.Data.Common;
using System.Data.Entity;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using TestEFPowerToolsCTP1.Entities;

namespace TestEFPowerToolsCTP1.Mapping
{
public class CustomerMap : EntityTypeConfiguration<Customer>
{
public CustomerMap()
{
// Primary Key
this.HasKey(t => t.CustomerID);

// Properties
this.Property(t => t.Title)
.HasMaxLength(8);

this.Property(t => t.FirstName)
.IsRequired()
.HasMaxLength(50);

this.Property(t => t.MiddleName)
.HasMaxLength(50);

this.Property(t => t.LastName)
.IsRequired()
.HasMaxLength(50);

this.Property(t => t.Suffix)
.HasMaxLength(10);

this.Property(t => t.CompanyName)
.HasMaxLength(128);

this.Property(t => t.SalesPerson)
.HasMaxLength(256);

this.Property(t => t.EmailAddress)
.HasMaxLength(50);

this.Property(t => t.Phone)
.HasMaxLength(25);

this.Property(t => t.TimeStamp)
.IsRequired()
.IsFixedLength()
.HasMaxLength(8);

// Table & Column Mappings
this.ToTable("Customers");
this.Property(t => t.CustomerID).HasColumnName("CustomerID");
this.Property(t => t.Title).HasColumnName("Title");
this.Property(t => t.FirstName).HasColumnName("FirstName");
this.Property(t => t.MiddleName).HasColumnName("MiddleName");
this.Property(t => t.LastName).HasColumnName("LastName");
this.Property(t => t.Suffix).HasColumnName("Suffix");
this.Property(t => t.CompanyName).HasColumnName("CompanyName");
this.Property(t => t.SalesPerson).HasColumnName("SalesPerson");
this.Property(t => t.EmailAddress).HasColumnName("EmailAddress");
this.Property(t => t.Phone).HasColumnName("Phone");
this.Property(t => t.ModifiedDate).HasColumnName("ModifiedDate");
this.Property(t => t.TimeStamp).HasColumnName("TimeStamp");
}
}
}

and the context:

using System;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using TestEFPowerToolsCTP1.Entities;
using TestEFPowerToolsCTP1.Mapping;

namespace TestEFPowerToolsCTP1
{
public class CustomersContext : DbContext
{
static CustomersContext()
{
Database.SetInitializer<CustomersContext>(null);
}

public DbSet<Customer> Customers { get; set; }
public DbSet<LineItem> LineItems { get; set; }
public DbSet<Order> Orders { get; set; }
public DbSet<Product> Products { get; set; }
public DbSet<sysdiagram> sysdiagrams { get; set; }
public DbSet<custview> custviews { get; set; }
public DbSet<vSalesOrderDetail> vSalesOrderDetails { get; set; }

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
modelBuilder.Configurations.Add(new CustomerMap());
modelBuilder.Configurations.Add(new LineItemMap());
modelBuilder.Configurations.Add(new OrderMap());
modelBuilder.Configurations.Add(new ProductMap());
modelBuilder.Configurations.Add(new sysdiagramMap());
modelBuilder.Configurations.Add(new custviewMap());
modelBuilder.Configurations.Add(new vSalesOrderDetailMap());
}
}
}

Very nice!

One of the suggestions in the comments on the team blog post is to be able to select which tables/views get reverse engineered.

原文连接：http://thedatafarm.com/blog/data-access/quick-look-at-reverse-engineer-db-into-code-first-classes/