mysql - EF5 :could not be created because the principal key columns could not be determined. 使用 AddForeignKey 流畅 API 完全指定外键

Question

我们正在使用Entity Framework 5.0。和数据库MySQL。当我们尝试迁移时间时出现异常。

could not be created because the principal key columns could not be determined. Use the AddForeignKey fluent API to fully specify the Foreign Key.

Answer 1

如此处所述 http://www.ozkary.com/2015/02/the-foreign-key-on-table-with-columns.html ，将 FK 放入不属于您的数据库上下文的表时可能会遇到问题

所以而不是这样做

CreateTable(
    "dbo.App",
    c => new
    {
        Id = c.Int(nullable: false, identity: true),
        Name = c.String(nullable: false, maxLength: 150),
        RoleId = c.String()
    })
    .PrimaryKey(t => t.Id)
    .ForeignKey("dbo.MyRoles", t => t.RoleId)
    .Index(t => t.RoleId);

你应该这样做:

CreateTable(
    "dbo.App",
    c => new
    {
        Id = c.Int(nullable: false, identity: true),
        Name = c.String(nullable: false, maxLength: 150),
        RoleId = c.String()
    })
    .PrimaryKey(t => t.Id)
    .Index(t => t.RoleId);

AddForeignKey("dbo.App", "RoleId", "dbo.Roles","Id");