Entity Framework 6 Code First新特性:支持存储过程

时间:2022-10-07 09:03:51

  Entity Framework 6提供支持存储过程的新特性,本文具体演示Entity Framework 6 Code First的存储过程操作。

Code First的插入/修改/删除存储过程

  默认情况下下,Code First配置对全部实体的插入/修改/删除操作均直接针对表进行。从EF6开始可以配置对全部或部分实体来选择使用存储过程。

1. 基本实体映射

1.1 通过Fluent API,配置使用插入/修改/删除存储过程

modelBuilder
.Entity<Blog>()
.MapToStoredProcedures();

1.2 Code First在数据库中生成存储过程的约定

  ◊ 生成三个存储过程,名称分别为<type_name>_Insert, <type_name>_Update, <type_name>_Delete

  ◊ 参数名对应于属性名 (注意:如果在 property上使用 HasColumnName() 或者 Column attribute 来重命名,那么参数也将使用这个重命名过的名称 );

  ◊ The insert stored procedure 为每一个属性都有一个参数,除了那些标记为数据库产生的(identity or computed),返回结果为那些标记为数据库产生的属性列;

  ◊ The update stored procedure 为每一个属性都有一个参数,除了那些标记为数据库产生且模式为 computed 的。一些并发标记的需要一个代表原始值的参数。返回值为那些 computed property 的列;

  ◊ The delete stored procedure 参数为实体主键(或者组合主键),此外也需要为每一个独立关联的外键准备一个参数(指那些没有在实体上定义相应外键属性的关系),一些并发标记的需要一个代表原始值的参数。

  示例:

  实体文件blog.cs:

using System;
using System.Collections.Generic; namespace EF6.Models
{
public partial class Blog
{
public int BlogID { get; set; }
public string Name { get; set; }
public string Url { get; set; }
}
}

  实体映射文件BlogMap.cs:

using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration; namespace EF6.Models.Mapping
{
public class BlogMap : EntityTypeConfiguration<Blog>
{
public BlogMap()
{
// Primary Key
this.HasKey(t => t.BlogID); // Properties
this.Property(t => t.Name)
.HasMaxLength(); this.Property(t => t.Url)
.HasMaxLength(); // Table & Column Mappings
this.ToTable("Blog");
this.Property(t => t.BlogID).HasColumnName("BlogID");
this.Property(t => t.Name).HasColumnName("Name");
this.Property(t => t.Url).HasColumnName("Url"); // Procedures
this.MapToStoredProcedures();
}
}
}

  在程序包管理器控制台中依次执行:

PM> Enable-Migrations -EnableAutomaticMigrations
PM> Add-Migration InitialCreate
PM> Update-Database -Verbose

  执行完成之后生成数据库:

Entity Framework 6 Code First新特性:支持存储过程

  监控生成数据的SQL语句:

CREATE TABLE [dbo].[Blog] (
[BlogID] [int] NOT NULL IDENTITY,
[Name] [nvarchar](50),
[Url] [nvarchar](100),
CONSTRAINT [PK_dbo.Blog] PRIMARY KEY ([BlogID])
CREATE PROCEDURE [dbo].[Blog_Insert]
@Name [nvarchar](50),
@Url [nvarchar](100)
AS
BEGIN
INSERT [dbo].[Blog]([Name], [Url])
VALUES (@Name, @Url) DECLARE @BlogID int
SELECT @BlogID = [BlogID]
FROM [dbo].[Blog]
WHERE @@ROWCOUNT > 0 AND [BlogID] = scope_identity() SELECT t0.[BlogID]
FROM [dbo].[Blog] AS t0
WHERE @@ROWCOUNT > 0 AND t0.[BlogID] = @BlogID
END
CREATE PROCEDURE [dbo].[Blog_Update]
@BlogID [int],
@Name [nvarchar](50),
@Url [nvarchar](100)
AS
BEGIN
UPDATE [dbo].[Blog]
SET [Name] = @Name, [Url] = @Url
WHERE ([BlogID] = @BlogID)
END
CREATE PROCEDURE [dbo].[Blog_Delete]
@BlogID [int]
AS
BEGIN
DELETE [dbo].[Blog]
WHERE ([BlogID] = @BlogID)
END

  2、重新默认约定

  2.1、重命名存储过程名称

modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
s.Update(u => u.HasName("Modify_Blog")));
modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
s.Update(u => u.HasName("Update_Blog"))
.Delete(d => d.HasName("Delete_Blog"))
.Insert(i => i.HasName("Insert_Bblog")));
modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
{
s.Update(u => u.HasName("Update_Blog"));
s.Delete(d => d.HasName("Delete_Blog"));
s.Insert(i => i.HasName("Insert_Blog"));
});
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration; namespace EF6.Models.Mapping
{
public class BlogMap : EntityTypeConfiguration<Blog>
{
public BlogMap()
{
// Primary Key
this.HasKey(t => t.BlogID); // Properties
this.Property(t => t.Name)
.HasMaxLength(); this.Property(t => t.Url)
.HasMaxLength(); // Table & Column Mappings
this.ToTable("Blog");
this.Property(t => t.BlogID).HasColumnName("BlogID");
this.Property(t => t.Name).HasColumnName("Name");
this.Property(t => t.Url).HasColumnName("Url"); // Procedures
this.MapToStoredProcedures(s =>{
s.Insert(u => u.HasName("Insert_Blog"));
s.Update(u => u.HasName("Update_Blog"));
s.Delete(u => u.HasName("Delete_Blog"));
});
}
}
}

  运行之后执行的SQL语句:

EXECUTE sp_rename @objname = N'dbo.Blog_Insert', @newname = N'Insert_Blog', @objtype = N'OBJECT'
EXECUTE sp_rename @objname = N'dbo.Blog_Update', @newname = N'Update_Blog', @objtype = N'OBJECT'
EXECUTE sp_rename @objname = N'dbo.Blog_Delete', @newname = N'Delete_Blog', @objtype = N'OBJECT'

  2.2、重命名存储过程参数名称

modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
s.Update(u => u.Parameter(b => b.BlogID, "Blog_ID")));
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration; namespace EF6.Models.Mapping
{
public class BlogMap : EntityTypeConfiguration<Blog>
{
public BlogMap()
{
// Primary Key
this.HasKey(t => t.BlogID); // Properties
this.Property(t => t.Name)
.HasMaxLength(); this.Property(t => t.Url)
.HasMaxLength(); // Table & Column Mappings
this.ToTable("Blog");
this.Property(t => t.BlogID).HasColumnName("BlogID");
this.Property(t => t.Name).HasColumnName("Name");
this.Property(t => t.Url).HasColumnName("Url"); // Procedures
this.MapToStoredProcedures(s =>
{
s.Update(u => u.Parameter(b => b.BlogID, "Blog_ID"));
});
}
}
}

  运行之后执行的SQL语句:

ALTER PROCEDURE [dbo].[Blog_Update]
@Blog_ID [int],
@Name [nvarchar](50),
@Url [nvarchar](100)
AS
BEGIN
UPDATE [dbo].[Blog]
SET [Name] = @Name, [Url] = @Url
WHERE ([BlogID] = @Blog_ID)
END
modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
s.Update(u => u.HasName("Update_Blog")
.Parameter(b => b.BlogID, "Blog_ID")
.Parameter(b => b.Name, "Blog_Name")
.Parameter(b => b.Url, "Blog_Url"))
.Delete(d => d.HasName("Delete_Blog")
.Parameter(b => b.BlogID, "Blog_ID"))
.Insert(i => i.HasName("Insert_Blog")
.Parameter(b => b.Name, "Blog_Name")
.Parameter(b => b.Url, "Blog_Url")));

  2.3、重命名数据库自动生成列的返回值的列名

modelBuilder
.Entity<Blog>()
.MapToStoredProcedures(s =>
s.Insert(i => i.Result(b => b.BlogID, "generated_blog_identity")));
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration; namespace EF6.Models.Mapping
{
public class BlogMap : EntityTypeConfiguration<Blog>
{
public BlogMap()
{
// Primary Key
this.HasKey(t => t.BlogID); // Properties
this.Property(t => t.Name)
.HasMaxLength(); this.Property(t => t.Url)
.HasMaxLength(); // Table & Column Mappings
this.ToTable("Blog");
this.Property(t => t.BlogID).HasColumnName("BlogID");
this.Property(t => t.Name).HasColumnName("Name");
this.Property(t => t.Url).HasColumnName("Url"); // Procedures
this.MapToStoredProcedures(s =>
{
s.Insert(i => i.Result(b => b.BlogID, "generated_blog_identity"));
});
}
}
}

  运行之后执行的SQL语句:

ALTER PROCEDURE [dbo].[Blog_Insert]
@Name [nvarchar](50),
@Url [nvarchar](100)
AS
BEGIN
INSERT [dbo].[Blog]([Name], [Url])
VALUES (@Name, @Url) DECLARE @BlogID int
SELECT @BlogID = [BlogID]
FROM [dbo].[Blog]
WHERE @@ROWCOUNT > 0 AND [BlogID] = scope_identity() SELECT t0.[BlogID] AS generated_blog_identity
FROM [dbo].[Blog] AS t0
WHERE @@ROWCOUNT > 0 AND t0.[BlogID] = @BlogID
END

  3、多对多关系

  两个多对多的实体类:

using System;
using System.Collections.Generic; namespace EF6.Models
{
public partial class Post
{
public int PostID { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public virtual ICollection<Tag> Tags { get; set; }
}
}
using System;
using System.Collections.Generic; namespace EF6.Models
{
public partial class Tag
{
public int TagID { get; set; }
public string TagName { get; set; }
public virtual ICollection<Post> Posts { get; set; }
}
}

  映射存储过程:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Post>()
.HasMany(p => p.Tags)
.WithMany(t => t.Posts)
.MapToStoredProcedures();
}

  默认生成的存储过程:

  ◊ 生成两个存储过程,命名为 <type_one><type_two>_Insert 和 <type_one><type_two>_Delete

  ◊ 参数为每一类型的主键(或组合主键),命名为 <type_name>_<property_name>

  代码运行后生成的存储过程:

CREATE PROCEDURE [dbo].[PostTag_Insert]
@Post_PostID [int],
@Tag_TagID [int]
AS
BEGIN
INSERT [dbo].[PostTags]([Post_PostID], [Tag_TagID])
VALUES (@Post_PostID, @Tag_TagID)
END
CREATE PROCEDURE [dbo].[PostTag_Delete]
@Post_PostID [int],
@Tag_TagID [int]
AS
BEGIN
DELETE [dbo].[PostTags]
WHERE (([Post_PostID] = @Post_PostID) AND ([Tag_TagID] = @Tag_TagID))
END

  参考资料:

  http://msdn.microsoft.com/en-us/data/dn468673