Question

我是 Asp.net MVC 5 EF6 的新手。我正在开发由Microsoft在asp.net网站上提供的Contoso Unversity应用程序。在第11章 实现继承 之后添加继承并通过迁移命令添加迁移它工作但是当我尝试将update-database命令应用于PMC时，我遇到了这个错误：

错误号码：15248，状态：1，类：11参数@objname是模棱两可或声称@objtype（OBJECT）是错误的。

这是My / inheritance迁移类的代码。请指导我修复。

namespace ContosoUniversity.Migrations
{
    using System;
    using System.Data.Entity.Migrations;

    public partial class Inheritance : DbMigration
    {
        public override void Up()
        {
            // Drop foreign keys and indexes that point to tables we're going to drop.
            DropForeignKey("dbo.Enrollment", "StudentID", "dbo.Student");
            DropIndex("dbo.Enrollment", new[] { "StudentID" });

            RenameTable(name: "dbo.Instructor", newName: "Person");
            AddColumn("dbo.Person", "EnrollmentDate", c => c.DateTime());
            AddColumn("dbo.Person", "Discriminator", c => c.String(nullable: false, maxLength: 128, defaultValue: "Instructor"));
            AlterColumn("dbo.Person", "HireDate", c => c.DateTime());
            AddColumn("dbo.Person", "OldId", c => c.Int(nullable: true));

            // Copy existing Student data into new Person table.
            Sql("INSERT INTO dbo.Person (LastName, FirstName, HireDate, EnrollmentDate, Discriminator, OldId) SELECT LastName, FirstName, null AS HireDate, EnrollmentDate, 'Student' AS Discriminator, ID AS OldId FROM dbo.Student");

            // Fix up existing relationships to match new PK's.
            Sql("UPDATE dbo.Enrollment SET StudentId = (SELECT ID FROM dbo.Person WHERE OldId = Enrollment.StudentId AND Discriminator = 'Student')");

            // Remove temporary key
            DropColumn("dbo.Person", "OldId");

            DropTable("dbo.Student");

            // Re-create foreign keys and indexes pointing to new table.
            AddForeignKey("dbo.Enrollment", "StudentID", "dbo.Person", "ID", cascadeDelete: true);
            CreateIndex("dbo.Enrollment", "StudentID");
        }

        public override void Down()
        {
            CreateTable(
                "dbo.Student",
                c => new
                    {
                        ID = c.Int(nullable: false, identity: true),
                        LastName = c.String(nullable: false, maxLength: 20),
                        FirstName = c.String(nullable: false, maxLength: 20),
                        EnrollmentDate = c.DateTime(nullable: false),
                    })
                .PrimaryKey(t => t.ID);

            AlterColumn("dbo.Person", "HireDate", c => c.DateTime(nullable: false));
            DropColumn("dbo.Person", "Discriminator");
            DropColumn("dbo.Person", "EnrollmentDate");
            RenameTable(name: "dbo.Person", newName: "Instructor");
        }
    }
}

Answer 1

考虑： 1.删除Migrations文件夹中的所有迁移文件 2.在连接字符串中重命名数据库 3.运行PM＆gt;添加迁移 4.运行PM＆gt;更新的数据库

ASP.net MVC 5 EF6错误更新数据库时

1 个答案: