我正在尝试使用以下映射来映射我的Team
和Match
表:
// Team.cs
public class Team
{
public virtual int ID { get; private set; }
public virtual string TeamName { get; set; }
public virtual Cup Cup { get; set; }
public virtual IList<Match> Matches { get; set; }
public Team()
{
Matches = new List<Match>();
}
}
public class TeamMap : ClassMap<Team>
{
public TeamMap()
{
Id(x => x.ID);
Map(x => x.TeamName).Not.Nullable();
References(x => x.Cup, "CupID");
HasMany(x => x.Matches)
.Key(x => x.Columns.Add("Team1ID", "Team2ID"))
.Inverse().Cascade.AllDeleteOrphan();
Table("Teams");
}
}
// Match.cs
public class Match
{
public virtual int ID { get; private set; }
public virtual Team Team1 { get; set; }
public virtual Team Team2 { get; set; }
public virtual int WinnerID { get; set; }
public virtual Cup Cup { get; set; }
}
public class MatchMap : ClassMap<Match>
{
public MatchMap()
{
Id(x => x.ID);
Map(x => x.WinnerID);
References(x => x.Team1, "Team1ID");
References(x => x.Team2, "Team2ID");
References(x => x.Cup, "CupID");
Table("Matches");
}
}
然而,它引发了一个例外:
外键 (FKEFFCA4CA45169AED:匹配[Team1ID, Team2ID]))必须具有相同的数量 列作为引用的主键 (团队[ID])
有什么建议吗?
更新
我能够根据@Yads写的评论将某些东西混合在一起来解决它。
我的代码:
// Team.cs
public class Team
{
public virtual int ID { get; private set; }
public virtual string TeamName { get; set; }
public virtual Cup Cup { get; set; }
public virtual IList<Match> HomeMatches { get; set; }
public virtual IList<Match> AwayMatches { get; set; }
public virtual IList<Match> Matches { get { return HomeMatches.Concat(AwayMatches).ToList(); }}
public Team()
{
HomeMatches = new List<Match>();
AwayMatches = new List<Match>();
}
}
public class TeamMap : ClassMap<Team>
{
public TeamMap()
{
Id(x => x.ID);
Map(x => x.TeamName).Not.Nullable();
References(x => x.Cup, "CupID");
HasMany(x => x.HomeMatches).KeyColumn("HomeTeamID")
.Inverse().Cascade.AllDeleteOrphan();
HasMany(x => x.AwayMatches).KeyColumn("AwayTeamID")
.Inverse().Cascade.AllDeleteOrphan();
Table("Teams");
}
}
// Match.cs
public class Match
{
public virtual int ID { get; private set; }
public virtual Team HomeTeam { get; set; }
public virtual Team AwayTeam { get; set; }
public virtual int WinnerID { get; set; }
public virtual Cup Cup { get; set; }
}
public class MatchMap : ClassMap<Match>
{
public MatchMap()
{
Id(x => x.ID);
Map(x => x.WinnerID);
References(x => x.HomeTeam, "HomeTeamID");
References(x => x.AwayTeam, "AwayTeamID");
References(x => x.Cup, "CupID");
Table("Matches");
}
}
但是,我不知道这种方法有什么缺点...... .Concat()对我来说似乎有点讨厌......
答案 0 :(得分:0)
我不知道为什么,但我觉得我之前已经回答了这个问题......
您正在看到的错误正在发生,因为您正在创建基于复合反向键的关联,该复合反向键无法映射到单个外键。
一种解决方案是尝试将您的“理想”关系模型装入您的对象模型,或者您可以丰富您的模型。我建议有一个丰富的模型来表达一个在比赛中出场的球队,你可以称之为Participation
。这将为你提供团队和比赛之间的多对多关系。
这样做的缺点是你需要将关系的基数表示为业务规则(因此你不能让三支球队参加同一场比赛)。
优点是您可以在参与者身上标记胜利者是谁,这样您就不需要在对象模型上有WinnerId
字段。
你最终会得到像这样使用的代码:
var match = new Match();
match.AddTeam(team1);
match.AddTeam(team2);
var winner = match.Participants.FindWinner();
winner = match.Winner; // alias for the above