mysql - MySql 中多对多关系的问题

Question

我正在将 EF Core 与 MySQL 结合使用，使用 SapientGuardian's EFCore library我正在尝试使用以下代码创建一个具有多对多关系的表；

        public class Personnel
        {
            public int Id { get; set; }

            [MaxLength(100)]
            public string Name { get; set; }

            public virtual ICollection<PersonnelDegree> PersonnelDegrees { get; set; }
        }

        public class Degree
        {
            public int Id { get; set; }

            [MaxLength(100)]
            public string Name { get; set; }

            public virtual ICollection<PersonnelDegree> PersonnelDegrees { get; set; }
        }

        public class PersonnelDegree
        {
            public int PersonnelId { get; set; }

            public int DegreeId { get; set; }

            public virtual Personnel Personnel { get; set; }

            public virtual Degree Degree { get; set; }
        }

        // Inside the OnModelCreating override
        builder.Entity<Degree>().HasMany(x => x.Personnel);
        builder.Entity<Personnel>().HasMany(x => x.Degrees);

        builder.Entity<PersonnelDegree>()
            .HasKey(x => new { x.DegreeId, x.PersonnelId });

        builder.Entity<PersonnelDegree>()
            .HasOne(x => x.Degree)
            .WithMany(x => x.PersonnelDegrees)
            .HasForeignKey(x => x.DegreeId);

        builder.Entity<PersonnelDegree>()
            .HasOne(x => x.Personnel)
            .WithMany(x => x.PersonnelDegrees)
            .HasForeignKey(x => x.PersonnelId);

现在，当我运行 dotnet ef 迁移时添加人员；我明白了...

        migrationBuilder.CreateTable(
            name: "Role",
            columns: table => new
            {
                Id = table.Column<int>(nullable: false)
                    .Annotation("MySQL:AutoIncrement", true),
                ApplicationId = table.Column<int>(nullable: true),
                Name = table.Column<string>(maxLength: 100, nullable: true),
                PersonnelId = table.Column<int>(nullable: true) // Where is this coming from?
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Role", x => x.Id);
                table.ForeignKey(
                    name: "FK_Role_Application_ApplicationId",
                    column: x => x.ApplicationId,
                    principalTable: "Application",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Restrict);
            });

请注意，角色的表定义中有 PersonnelId 列。人员表有 RoleId 吗？谁能告诉我这是怎么回事？

Answer 1

我有相同的模型，但 OnModelCreating 方法不同。

所以我假设您配置错误。对于您的情况应该是这样的:

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<PersonnelDegree>()
            .HasKey(t => new { t.PersonnelId , t.DegreeId });
    }

这就是您的 OnModelCreating 方法中应该拥有的全部内容。