Question

我有两个实体框架代码第一个POCO。我可以轻松地将新的站点和技术项目插入到数据库中，但我似乎无法将站点与技术相关联。当我这样做......

if(!site.Technologies.Any( o => (o.Name == technology.Name &&  technology.Source == source)))
{
  site.Technologies.Add(technology);
  technology.Sites.Add(site);
}

我收到重复的密钥错误。如果我从条件中删除第二行，则连接表TechnologiesSites不会获得任何记录！如何在EF Code First中插入？

public class Site
{
    public Site()
    {
        Technologies = new HashSet<Technology>();
    }

    [Key]
    public string Hostname { get; set; }
    public virtual ICollection<Technology> Technologies { get; set; }
}

和

public class Technology
{
    [Key, Column(Order = 0)]
    public string Name { get; set; }
    [Key, Column(Order = 1)]
    public string Source { get; set; }
    public virtual ICollection<Site> Sites { get; set; }

    public Technology()
    {
        Sites = new HashSet<Site>();
    }
}

Answer 1

您必须检查两个方向：

if(!site.Technologies.Any( o => (o.Name == technology.Name &&  technology.Source == source)) &&
!technology.Sites.Any(x => x.Hostname == site.Hostname)
)
{
  site.Technologies.Add(technology);
  technology.Sites.Add(site);
}

EF代码优先：连接表为空

1 个答案: