我想将 table ID 用于不同的 table，它需要两个 tables ID，Entity Framework，代码优先

Question

这只是我快速完成的事情，但它显示了我想要的样子。 OBS数据库图table图片。所以我想让Teamtable和Transfertable有两个关系（OldTeamId，NewTeamId），这样可以吗？

当我尝试按现在的样子执行 Add-Migration 时，我收到一条消息

Unable to determine the relationship represented by navigation property 'Team.OldTeams' of type 'List'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'

代码：

public class Transfer
{
    public int Id { get; set; }
    public DateTime TransferDate { get; set; }
    public Player ThePlayer { get; set; }
    public string PlayerId { get; set; }
    public Team OldTeam { get; set; }
    public int OldTeamId { get; set; }
    public Team NewTeam { get; set; }
    public int NewTeamId { get; set; }
}

public class Team
{
    public Team()
    {
        Tournaments = new List<Tournament>();
        Players = new List<TeamPlayer>();
        OldTeams = new List<Transfer>();
        NewTeams = new List<Transfer>();
    }

    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public byte[] TeamLogo { get; set; }
    public DateTime Founded { get; set; }
    public Country TheCountry { get; set; }
    public int CountryId { get; set; }
    public List<Tournament> Tournaments { get; set; }
    public List<TeamPlayer> Players { get; set; }
    public List<Transfer> OldTeams { get; set; }
    public List<Transfer> NewTeams { get; set; }
}

public class GamepediaContext : DbContext
{
    public DbSet<Country> Countries { get; set; }
    public DbSet<Map> Maps { get; set; }
    public DbSet<Player> Players { get; set; }
    public DbSet<Team> Teams { get; set; }
    public DbSet<TeamPlayer> TeamPlayers { get; set; }
    public DbSet<Tournament> Tournaments { get; set; }
    public DbSet<TournamentMap> TournamentMaps { get; set; }
    public DbSet<Transfer> Transfers { get; set; }
}



[1]: https://i.stack.imgur.com/Y8Set.png

Answer 1

使用 foreignKey 属性

public class Transfer
{
    public int Id { get; set; }
    public DateTime TransferDate { get; set; }
    public Player ThePlayer { get; set; }
    public string PlayerId { get; set; }   
    public Team OldTeam { get; set; }
    [ForeignKey("OldTeam")]
    public int OldTeamId { get; set; }
    public Team NewTeam { get; set; }
    [ForeignKey("NewTeam")]
    public int NewTeamId { get; set; }
}

Answer 2

我让它工作了，我添加了这行代码。我将脚本 "onDelete" 从 Cascade 更改为 NoAction。

modelBuilder.Entity<Team>().HasMany(m => m.OldTeams).WithOne(m => m.OldTeam).HasForeignKey(m => m.OldTeamId);
        modelBuilder.Entity<Team>().HasMany(m => m.NewTeams).WithOne(m => m.NewTeam).HasForeignKey(m => m.NewTeamId);

我想将 table ID 用于不同的 table，它需要两个 tables ID，Entity Framework，代码优先

I want to use a table ID to a different table that takes two of that tables ID, Entity Framework, code first

c#

sql

entity-framework

database-migration

code-first