实体框架codeFirst许多与其他信息一对多的关系 [英] Entity Framework CodeFirst many to many relationship with additional information
本文介绍了实体框架codeFirst许多与其他信息一对多的关系的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有以下型号:
class Contract
{
string ContractID{get;set;}
ICollection<Part> Parts{get;set;}
}
class Part
{
string PartID{get;set;}
ICollection<Contract> Contracts{get;set;}
}
问题是,部分与合同之间的关系还包含以下附加信息:
the problem is that the relationship between Part and Contract also contains the following additional information :
class ContractParts
{
Contract{get;set;}
Part{get;set;}
Date{get;set;} //additional info
Price{get;set;} //additional info
}
我怎么会写实体语境呢?
How would I write the Entity Context for this ?
推荐答案
在这种情况下,你必须符合您的实体是这样的:
In such case you must model your entities this way:
public class Contract
{
public virtual string ContractId { get; set; }
public virtual ICollection<ContractPart> ContractParts { get; set; }
}
public class Part
{
public virtual string PartId { get;set; }
public virtual ICollection<ContractPart> ContractParts { get; set; }
}
public class ContractPart
{
public virtual string ContractId { get; set; }
public virtual string PartId { get; set; }
public virtual Contract Contract { get; set; }
public virtual Part Part { get; set; }
public virtual string Date { get; set; } //additional info
public virtual decimal Price { get; set; } //additional info
}
在派生背景下,你必须定义:
In derived context you must define:
protected override void OnModelCreateing(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<ContractPart>()
.HasKey(cp => new { cp.ContractId, cp.PartId });
modelBuilder.Entity<Contract>()
.HasMany(c => c.ContractParts)
.WithRequired()
.HasForeignKey(cp => cp.ContractId);
modelBuilder.Entity<Part>()
.HasMany(p => p.ContractParts)
.WithRequired()
.HasForeignKey(cp => cp.PartId);
}
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