public CustomerMap()
{
this.ToTable("Customer");
this.HasKey(c => c.Id);
this.Property(u => u.Username).HasMaxLength(1000);
this.Property(u => u.Email).HasMaxLength(1000);
this.Property(u => u.EmailToRevalidate).HasMaxLength(1000);
this.Property(u => u.SystemName).HasMaxLength(400);

//多对多
this.HasMany(c => c.CustomerRoles)
.WithMany()//没有传任何参数则代表对方没有导航属性到此实体
.Map(m => m.ToTable("Customer_CustomerRole_Mapping")); 

//一对一，但BillingAddress表没有导航到Customer的属性，此customer生成的字段BillingAddress_Id是可以为空的
this.HasOptional(c => c.BillingAddress); 
}

===============================================================================================

public partial class CustomerAttributeValueMap : NopEntityTypeConfiguration<CustomerAttributeValue>
{
public CustomerAttributeValueMap()
{
this.ToTable("CustomerAttributeValue");
this.HasKey(cav => cav.Id);
this.Property(cav => cav.Name).IsRequired().HasMaxLength(400);
//一对多，双方都有导航属性
this.HasRequired(cav => cav.CustomerAttribute)
.WithMany(ca => ca.CustomerAttributeValues)
.HasForeignKey(cav => cav.CustomerAttributeId);
}
}

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