Linq to Entities插入，删除外键关系 [英] Linq to Entities Insert, Delete on Foreign key relation

问题描述

HI



我有问题通过linq将表上的记录插入实体，其中两个表用外键连接。



我的第一张桌子是

 创建 表 [dbo]。[Emp]（
 [Id] [ int ]  IDENTITY （ 1 ， 1 ） NOT   NULL ，
 [EmpName] [ varchar ]（ 50 ） NULL ，
  CONSTRAINT  [PK_Emp]  PRIMARY   KEY   CLUSTERED  
（
 [Id]  ASC  
） WITH （PAD _INDEX =  OFF ，STATISTICS_NORECOMPUTE =  OFF ，IGNORE_DUP_KEY =  OFF ，ALLOW_ROW_LOCKS =  ON ，ALLOW_PAGE_LOCKS =  ON ） ON  [ PRIMARY ] 
） ON  [ PRIMARY ] 

和第二张表是

 创建 表 [dbo ]。[EMpSecond]（
 [Id] [ int ]  NOT   NULL ，
 [EmpAge] [ int ]  NULL  
） ON  [ PRIMARY ] 
 
  GO  
 
  ALTER   TABLE  [dbo]。 [EMpSecond]  WITH   CHECK   ADD   FOREIGN   KEY （[Id]）
  REFERENCES  [dbo]。[Emp]（[Id]）

我的插入C＃代码是

 Emp emp =  new  Emp（）; 
 emp.EmpName = txtName.Text; 
 emp.Id = Convert.ToInt32（txtId.Text）; 
 
 EMpSecond sec =  new  EMpSecond（）; 
 sec.EmpAge = Convert.ToInt32（txtAge.Text）; 
 sec.Id = Convert.ToInt32（txtId.Text）; 
  //   sec.Emp.Id = emp.Id;  
 
 使用（TestEntities testEntities =  new  TestEntities（））
 {
 testEntities .AddToEmps（EMP）; 
 testEntities.SaveChanges（）; 
 
 testEntities.AddToEMpSeconds（sec）; 
 testEntities.SaveChanges（）; 
} 

请给我解决方案，紧急

解决方案

< blockquote>

 Emp emp = new Emp（）; 
 emp.EmpName = txtName.Text; 
 emp.Id = Convert.ToInt32（txtId.Text）; //这不应该是用户可输入的，ID是由DB 
 
生成的EMpSecond sec = new EMpSecond（）; 
 sec.EmpAge = Convert.ToInt32（txtAge.Text）; 
 sec.Id = Convert.ToInt32（txtId.Text）; 
 //sec.Emp.Id = emp.Id; 
 
使用（TestEntities testEntities = new TestEntities（））
 {
 testEntities.AddToEmps（emp）; 
 testEntities.SaveChanges（）; 
 //保存一旦发生，则在saveChanges（）调用
 sec.Id = emp.Id之后将填充emp.Id; //当emp添加到DB时，此行将sec.Id设置为新创建的ID。 
 testEntities.AddToEMpSeconds（sec）; 
 testEntities.SaveChanges（）; 
} 

HI

I have problem to insert records on table through linq to entities, where two tables are connected with foreign key.

My first table is

CREATE TABLE [dbo].[Emp](
	[Id] [int] IDENTITY(1,1) NOT NULL,
	[EmpName] [varchar](50) NULL,
 CONSTRAINT [PK_Emp] PRIMARY KEY CLUSTERED 
(
	[Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

and second table is

CREATE TABLE [dbo].[EMpSecond](
	[Id] [int] NOT NULL,
	[EmpAge] [int] NULL
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[EMpSecond]  WITH CHECK ADD FOREIGN KEY([Id])
REFERENCES [dbo].[Emp] ([Id])

my insertion C# code is

Emp emp = new Emp();
            emp.EmpName = txtName.Text;
            emp.Id = Convert.ToInt32(txtId.Text);

            EMpSecond sec = new EMpSecond();
            sec.EmpAge = Convert.ToInt32(txtAge.Text);
            sec.Id = Convert.ToInt32(txtId.Text);
            //sec.Emp.Id = emp.Id;

            using (TestEntities testEntities = new TestEntities())
            {
                testEntities.AddToEmps(emp);
                testEntities.SaveChanges();

                testEntities.AddToEMpSeconds(sec);
                testEntities.SaveChanges();
            }

please give me solution, its urgent

解决方案

Emp emp = new Emp();
            emp.EmpName = txtName.Text;
            emp.Id = Convert.ToInt32(txtId.Text); // this should not be user enterable, ID's are generated by DB
 
            EMpSecond sec = new EMpSecond();
            sec.EmpAge = Convert.ToInt32(txtAge.Text);
            sec.Id = Convert.ToInt32(txtId.Text);
            //sec.Emp.Id = emp.Id;

            using (TestEntities testEntities = new TestEntities())
            {
                testEntities.AddToEmps(emp);
                testEntities.SaveChanges();
// once the save occurs, then the emp.Id will be populated after saveChanges() called
 sec.Id = emp.Id; // this line sets the sec.Id to the newly created ID when emp was added to DB.
                testEntities.AddToEMpSeconds(sec);
                testEntities.SaveChanges();
            }

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