实体框架 - 使用外键删除对象，保留父项 [英] Entity Framework - Remove object with foreign key, preserving parent

问题描述

我有以下模型：

public class Company
{
    //Primary key
    public string ID { get; set; } 

    //Foreign key
    public int? LogotypeID { get; set; }
}

和

public class Logotype
{
    //Primary key
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int? ID { get; set; }

    //Foreign key
    public string CompanyID { get; set; }
}

如何从公司表格中删除标识， 删除公司行？

How do I delete the logotype from the Company table, without removing the company row?

使用：

http://msdn.microsoft.com/en-us/library/system.data.entity .dbset.remove（v = vs.113）.aspx
DbSet.Remove（Logotype）有以下异常：

Using:
http://msdn.microsoft.com/en-us/library/system.data.entity.dbset.remove(v=vs.113).aspx DbSet.Remove(Logotype) thows the following exception:

{"The DELETE statement conflicted with the REFERENCE constraint \"FK_dbo.Companies_dbo.Logotypes_LogotypeID\". The conflict occurred in database \"ShipReg\", table \"dbo.Companies\", column 'LogotypeID'.\r\nThe statement has been terminated."}

任何想法？

Br，
Tim

Br, Tim

推荐答案

添加公司中的虚拟财产如

add a virtual property in company like

public class Company
{
//Primary key
public string ID { get; set; } 

//Foreign key
public int? LogotypeID { get; set; }

public virtual Logotype Logotype {get;set;}

}
然后

dbContext.Entry<Company>(company).State=EntityState.Modified;
dbContext.Entry<Logotype>(company.Logotype).State=EntityState.Deleted;

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