聲明:本文只針對 EF6+
默認情況下,Code First 對實體進行插入、更新、刪除操作是直接在表上進行的,從 EF6 開始你可以選擇使用存儲過程(Stored Procedures)
簡單實體映射 Basic Entity Mapping
注意:本文將使用 Fluent API 來配置使用存儲過程

public class Blog { public int BlogId { get; set; } public string Name { get; set; } public string Url { get; set; } [Timestamp] public byte[] Timestamp { get; set; } public virtual ICollection<Post> Posts { get; set; } }
modelBuilder.Entity<Blog>()
.MapToStoredProcedures();
上面的代碼執行后,Code First 將利用某些約定在數據庫中生成一些存儲過程:
- 生成三個存儲過程,名稱分別為<type_name>_Insert, <type_name>_Update, <type_name>_Delete (本例為 Blog_Insert, Blog_Update, Blog_Delete);
- 參數名對應於屬性名 (注意:如果在 property上使用 HasColumnName() 或者 Column attribute 來重命名,那么參數也將使用這個重命名過的名稱 );
- The insert stored procedure 為每一個屬性都有一個參數,除了那些標記為數據庫產生的(identity or computed),返回結果為那些標記為數據庫產生的屬性列;
- The update stored procedure 為每一個屬性都有一個參數,除了那些標記為數據庫產生且模式為 computed 的。一些並發標記的需要一個代表原始值的參數(更多信息請參考 Concurrency Tokens section)。返回值為那些 computed property 的列;
- The delete stored procedure 參數為實體主鍵(或者組合主鍵),此外也需要為每一個獨立關聯的外鍵准備一個參數(指那些沒有在實體上定義相應外鍵屬性的關系),一些並發標記的需要一個代表原始值的參數(更多信息請參考 Concurrency Tokens section)
存儲過程的具體內容如下

CREATE PROCEDURE [dbo].[Blog_Insert] @Name [nvarchar](max), @Url [nvarchar](max) 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], t0.[Timestamp] FROM [dbo].[Blog] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[BlogId] = @BlogId END CREATE PROCEDURE [dbo].[Blog_Update] @BlogId [int], @Name [nvarchar](max), @Url [nvarchar](max), @Timestamp_Original [rowversion] AS BEGIN UPDATE [dbo].[Blog] SET [Name] = @Name, [Url] = @Url WHERE (([BlogId] = @BlogId) AND (([Timestamp] = @Timestamp_Original) OR ([Timestamp] IS NULL AND @Timestamp_Original IS NULL))) SELECT t0.[Timestamp] FROM [dbo].[Blog] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[BlogId] = @BlogId END CREATE PROCEDURE [dbo].[Blog_Delete] @BlogId [int], @Timestamp_Original [rowversion] AS BEGIN DELETE [dbo].[Blog] WHERE (([BlogId] = @BlogId) AND (([Timestamp] = @Timestamp_Original) OR ([Timestamp] IS NULL AND @Timestamp_Original IS NULL))) END
Overriding the Defaults
你可以重寫部分或全部的默認配置
重寫存儲過程名
重寫 update 存儲過程名
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.HasName("modify_blog")));
重寫所有的存儲過程名
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.HasName("modify_blog")) .Delete(d => d.HasName("delete_blog")) .Insert(i => i.HasName("insert_blog")));
效果與下面使用一樣 lambda block syntax
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => { s.Update(u => u.HasName("modify_blog")); s.Delete(d => d.HasName("delete_blog")); s.Insert(i => i.HasName("insert_blog")); });
重寫存儲過程參數名
modelBuilder .Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.Parameter(b => b.BlogId, "blog_id")));
上面所有的操作都是可組合的和鏈式的,如如下示例重命名所有的存儲過程及其參數名
modelBuilder .Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.HasName("modify_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")));
重命名數據庫產生的返回列名
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Insert(i => i.Result(b => b.BlogId, "generated_blog_identity")));
CREATE PROCEDURE [dbo].[Blog_Insert] @Name [nvarchar](max), @Url [nvarchar](max) 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, t0.[Timestamp] FROM [dbo].[Blog] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[BlogId] = @BlogId END
無外鍵關系 Relationships Without a Foreign Key in the Class
如果實體上有定義外鍵屬性,那么其重命名操作與其它屬性無異。如果實體間的關系存在,但是並沒定義外鍵屬性,那么默認的參數名為 <navigation_property_name>_<primary_key_name>

public class Blog { public int BlogId { get; set; } public string Name { get; set; } public string Url { get; set; } public List<Post> Posts { get; set; } } public class Post { public int PostId { get; set; } public string Title { get; set; } public string Content { get; set; } public Blog Blog { get; set; } }
如上類定義將會導致在 Insert 和 Update Post 存儲過程中產生參數 Blog_BlogId

CREATE PROCEDURE [dbo].[Post_Insert] @Title [nvarchar](max), @Content [nvarchar](max), @Blog_BlogId [int] AS BEGIN INSERT [dbo].[Post]([Title], [Content], [Blog_BlogId]) VALUES (@Title, @Content, @Blog_BlogId) DECLARE @PostId int SELECT @PostId = [PostId] FROM [dbo].[Post] WHERE @@ROWCOUNT > 0 AND [PostId] = scope_identity() SELECT t0.[PostId] FROM [dbo].[Post] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[PostId] = @PostId END CREATE PROCEDURE [dbo].[Post_Update] @PostId [int], @Title [nvarchar](max), @Content [nvarchar](max), @Blog_BlogId [int] AS BEGIN UPDATE [dbo].[Post] SET [Title] = @Title, [Content] = @Content, [Blog_BlogId] = @Blog_BlogId WHERE ([PostId] = @PostId) END
Overriding the Defaults
通過提供主鍵屬性給 Parameter 方法,你可以重命名在類中沒有包含的外鍵參數名
modelBuilder.Entity<Post>() .MapToStoredProcedures(s => s.Insert(i => i.Parameter(p => p.Blog.BlogId, "blog_id")));
生成的 Insert 存儲過程如下
CREATE PROCEDURE [dbo].[Post_Insert] @Title [nvarchar](max), @Content [nvarchar](max), @blog_id [int] AS BEGIN INSERT [dbo].[Post]([Title], [Content], [Blog_BlogId]) VALUES (@Title, @Content, @blog_id) DECLARE @PostId int SELECT @PostId = [PostId] FROM [dbo].[Post] WHERE @@ROWCOUNT > 0 AND [PostId] = scope_identity() SELECT t0.[PostId] FROM [dbo].[Post] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[PostId] = @PostId END
如果在從屬實體(dependent entity)上沒有導航屬性(navigation property)(例如 Post.Blog),你可以使用 Navigation(原文是 Association 方法,但筆者發現根本沒有此方法) 方法來確定另一端的關系然后為相應的主鍵(或組合主鍵)配置參數
public class Post { public int PostId { get; set; } public string Title { get; set; } public string Content { get; set; } }
modelBuilder.Entity<Post>() .MapToStoredProcedures(s => s.Insert(i => i.Navigation<Blog>( b => b.Posts, c => c.Parameter(b => b.BlogId, "blog_id"))));
產生的存儲過程如下
CREATE PROCEDURE [dbo].[Post_Insert] @Title [nvarchar](max), @Content [nvarchar](max), @blog_id [int] AS BEGIN INSERT [dbo].[Post]([Title], [Content], [Blog_BlogId]) VALUES (@Title, @Content, @blog_id) DECLARE @PostId int SELECT @PostId = [PostId] FROM [dbo].[Post] WHERE @@ROWCOUNT > 0 AND [PostId] = scope_identity() SELECT t0.[PostId] FROM [dbo].[Post] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[PostId] = @PostId END
並發標記 Concurrency Tokens
Update 和 Delete 存儲過程也需要處理並發問題:
- 如果實體包含並發標記,存儲過程可選擇地有一個 Output 參數用於返回更新/刪除的列的數目,這樣一個參數必須通過方法 RowsAffectedParameter 配置(注意:EF 默認使用 ExecuteNonQuery 的返回值來確定有多少行受影響,如果你在存儲過程中執行邏輯操作將導致 ExecuteNonQuery 的返回值是錯誤的,此時指定一個行影響的 Output 參數是有必要的);
- 每一個並發標記,都有一個參數,命名為 <property_name>_Original (如 Timestamp_Original),這個參數將傳遞屬性的原始值 - 從數據庫查詢的值
- 數據庫計算(computed)的並發標記 - 例如 timestamp - 將有一個原始值參數;
- 非計算屬性的並發標記在 Update 存儲過程中也有一個更新值參數,只是使用之前討論過的為新值的命名約定。此處的一個例子為用 Blog 的 URL 作為並發標記,更新后的新值是必須的因為這個值可能被你的代碼更新成另一個新值(不像 Timestamp 標記只能被數據庫更新)
一個計算並發標記(timestamp)標記的例子
public class Blog { public int BlogId { get; set; } public string Name { get; set; } public string Url { get; set; } [Timestamp] public byte[] Timestamp { get; set; } }
modelBuilder.Entity<Blog>()
.MapToStoredProcedures();
CREATE PROCEDURE [dbo].[Blog_Update] @BlogId [int], @Name [nvarchar](max), @Url [nvarchar](max), @Timestamp_Original [rowversion] AS BEGIN UPDATE [dbo].[Blog] SET [Name] = @Name, [Url] = @Url WHERE (([BlogId] = @BlogId) AND (([Timestamp] = @Timestamp_Original) OR ([Timestamp] IS NULL AND @Timestamp_Original IS NULL))) SELECT t0.[Timestamp] FROM [dbo].[Blog] AS t0 WHERE @@ROWCOUNT > 0 AND t0.[BlogId] = @BlogId END
一個非計算並發標記(URL)例子
public class Blog { public int BlogId { get; set; } public string Name { get; set; } [ConcurrencyCheck] public string Url { get; set; } }
CREATE PROCEDURE [dbo].[Blog_Update] @BlogId [int], @Name [nvarchar](max), @Url [nvarchar](max), @Url_Original [nvarchar](max) AS BEGIN UPDATE [dbo].[Blog] SET [Name] = @Name, [Url] = @Url WHERE (([BlogId] = @BlogId) AND (([Url] = @Url_Original) OR ([Url] IS NULL AND @Url_Original IS NULL))) END
Overriding the Defaults
使用 RowsAffectedParameter 方法
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.RowsAffectedParameter("rows_affected")));
CREATE PROCEDURE [dbo].[Blog_Update] @BlogId [int], @Name [nvarchar](max), @Url [nvarchar](max), @Url_Original [nvarchar](max), @rows_affected [int] OUT AS BEGIN UPDATE [dbo].[Blog] SET [Name] = @Name, [Url] = @Url WHERE (([BlogId] = @BlogId) AND (([Url] = @Url_Original) OR ([Url] IS NULL AND @Url_Original IS NULL))) SET @rows_affected = @@ROWCOUNT END
對於計算並發標記 - 只有原始值需要傳遞 - 我們可以使用標准的 Pameter 方法來重命名參數名
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.Parameter(b => b.Timestamp, "blog_timestamp")));
對於非計算並發標記 - 原始值和更新值都需傳遞 - 我們可以使用 Parameter 方法的重載版本來為每一個參數重命名
modelBuilder.Entity<Blog>() .MapToStoredProcedures(s => s.Update(u => u.Parameter(b => b.Url, "blog_url", "blog_original_url")));
N:N 關系 Many to Many Relationships
定義如下類
public class Post { public int PostId { get; set; } public string Title { get; set; } public string Content { get; set; } public virtual ICollection<Tag> Tags { get; set; } } public class Tag { public int TagId { get; set; } public string TagName { get; set; } public virtual ICollection<Post> Posts { get; set; } }
映射到存儲過程
modelBuilder.Entity<Post>() .HasMany(p => p.Tags) .WithMany(t => t.Posts) .MapToStoredProcedures();
默認生成的存儲過程如下:
- 生成兩個存儲過程,命名為 <type_one><type_two>_Insert 和 <type_one><type_two>_Delete (本例中為 PostTag_Insert 和PostTag_Delete);
- 參數為每一類型的主鍵(或組合主鍵),命名為 <type_name>_<property_name> (本例為 Post_PostId 和 Tag_TagId)
CREATE PROCEDURE [dbo].[PostTag_Insert] @Post_PostId [int], @Tag_TagId [int] AS BEGIN INSERT [dbo].[PostTag]([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].[PostTag] WHERE (([Post_PostId] = @Post_PostId) AND ([Tag_TagId] = @Tag_TagId)) END
Overriding the Defaults
可以像配置實體存儲過程一樣來配置此存儲過程和參數的名稱
modelBuilder.Entity<Post>() .HasMany(p => p.Tags) .WithMany(t => t.Posts) .MapToStoredProcedures(s => s.Insert(i => i.HasName("add_post_tag") .LeftKeyParameter(p => p.PostId, "post_id") .RightKeyParameter(t => t.TagId, "tag_id")) .Delete(d => d.HasName("remove_post_tag") .LeftKeyParameter(p => p.PostId, "post_id") .RightKeyParameter(t => t.TagId, "tag_id")));
產生的存儲過程如下
CREATE PROCEDURE [dbo].[add_post_tag] @post_id [int], @tag_id [int] AS BEGIN INSERT [dbo].[PostTag]([Post_PostId], [Tag_TagId]) VALUES (@post_id, @tag_id) END CREATE PROCEDURE [dbo].[remove_post_tag] @post_id [int], @tag_id [int] AS BEGIN DELETE [dbo].[PostTag] WHERE (([Post_PostId] = @post_id) AND ([Tag_TagId] = @tag_id)) END