EF Core 迁移重新创建重命名的表

Question

我正在使用 .NET 5 Identity 包并重命名它的表并使用IdentityUser. 现在，我决定向我的表添加一些属性User并应用迁移，但迁移尝试重新创建我的重命名表。

这是我的用户模型：

public class User : IdentityUser<int>, IUser
{
    public string Password { get; set; }

    public string Username { get => base.UserName; set => base.UserName = value; }
    public string Name { get; set; }

    public bool PubliclyVisible { get; set; } //New
    public IEnumerable<User> Trackers { get; set; } //New
    public IEnumerable<User> Tracked { get; set; } //New

}

我的DbContext扩展模型配置：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{

    base.OnModelCreating(modelBuilder);
    modelBuilder.Entity<User>(b =>
    {
        b.ToTable("Users");
        b.HasMany(b => b.Tracked); //New
        b.HasMany(b => b.Trackers); //New 
        b.Ignore(u => u.Username);
                
    });

    modelBuilder.Entity<GPSData>().HasOne(d => d.User);

    modelBuilder.Entity<IdentityUserClaim<int>>(b => b.ToTable("UserClaims"));
    modelBuilder.Entity<IdentityUserLogin<int>>(b => b.ToTable("UserLogins"));
    modelBuilder.Entity<IdentityUserToken<int>>(b => b.ToTable("UserTokens"));
    modelBuilder.Entity<IdentityRole>(b => b.ToTable("Roles"));
    modelBuilder.Entity<IdentityRoleClaim<int>>(b => b.ToTable("RoleClaims"));
    modelBuilder.Entity<IdentityUserRole<int>>(b => b.ToTable("UserRoles"));

}

我在配置中标记了新属性User以及配置中的附加行//New。

我跑完之后add-migration AddedTrackingProperties

我得到以下迁移，尝试重新创建我的表，因此AspNetUserRoles当我更新表时，我得到一个已经存在的错误。

迁移配置

public partial class AddedTrackingProperties : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.CreateTable(
            name: "AspNetRoles",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                Name = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                NormalizedName = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                ConcurrencyStamp = table.Column<string>(type: "nvarchar(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_AspNetRoles", x => x.Id);
            });

        migrationBuilder.CreateTable(
            name: "Roles",
            columns: table => new
            {
                Id = table.Column<string>(type: "nvarchar(450)", nullable: false),
                Name = table.Column<string>(type: "nvarchar(max)", nullable: true),
                NormalizedName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                ConcurrencyStamp = table.Column<string>(type: "nvarchar(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Roles", x => x.Id);
            });

        migrationBuilder.CreateTable(
            name: "Users",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                Password = table.Column<string>(type: "nvarchar(max)", nullable: true),
                Name = table.Column<string>(type: "nvarchar(max)", nullable: true),
                PubliclyVisible = table.Column<bool>(type: "bit", nullable: false),
                UserName = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                NormalizedUserName = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                Email = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                NormalizedEmail = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                EmailConfirmed = table.Column<bool>(type: "bit", nullable: false),
                PasswordHash = table.Column<string>(type: "nvarchar(max)", nullable: true),
                SecurityStamp = table.Column<string>(type: "nvarchar(max)", nullable: true),
                ConcurrencyStamp = table.Column<string>(type: "nvarchar(max)", nullable: true),
                PhoneNumber = table.Column<string>(type: "nvarchar(max)", nullable: true),
                PhoneNumberConfirmed = table.Column<bool>(type: "bit", nullable: false),
                TwoFactorEnabled = table.Column<bool>(type: "bit", nullable: false),
                LockoutEnd = table.Column<DateTimeOffset>(type: "datetimeoffset", nullable: true),
                LockoutEnabled = table.Column<bool>(type: "bit", nullable: false),
                AccessFailedCount = table.Column<int>(type: "int", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Users", x => x.Id);
            });

        migrationBuilder.CreateTable(
            name: "RoleClaims",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                RoleId = table.Column<int>(type: "int", nullable: false),
                ClaimType = table.Column<string>(type: "nvarchar(max)", nullable: true),
                ClaimValue = table.Column<string>(type: "nvarchar(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_RoleClaims", x => x.Id);
                table.ForeignKey(
                    name: "FK_RoleClaims_AspNetRoles_RoleId",
                    column: x => x.RoleId,
                    principalTable: "AspNetRoles",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "GPSData",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                Longitude = table.Column<double>(type: "float", nullable: false),
                Latitude = table.Column<double>(type: "float", nullable: false),
                Speed = table.Column<double>(type: "float", nullable: false),
                Timestamp = table.Column<DateTime>(type: "datetime2", nullable: false),
                UserId = table.Column<int>(type: "int", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_GPSData", x => x.Id);
                table.ForeignKey(
                    name: "FK_GPSData_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "UserClaims",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                UserId = table.Column<int>(type: "int", nullable: false),
                ClaimType = table.Column<string>(type: "nvarchar(max)", nullable: true),
                ClaimValue = table.Column<string>(type: "nvarchar(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserClaims", x => x.Id);
                table.ForeignKey(
                    name: "FK_UserClaims_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "UserLogins",
            columns: table => new
            {
                LoginProvider = table.Column<string>(type: "nvarchar(450)", nullable: false),
                ProviderKey = table.Column<string>(type: "nvarchar(450)", nullable: false),
                ProviderDisplayName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                UserId = table.Column<int>(type: "int", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserLogins", x => new { x.LoginProvider, x.ProviderKey });
                table.ForeignKey(
                    name: "FK_UserLogins_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "UserRoles",
            columns: table => new
            {
                UserId = table.Column<int>(type: "int", nullable: false),
                RoleId = table.Column<int>(type: "int", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserRoles", x => new { x.UserId, x.RoleId });
                table.ForeignKey(
                    name: "FK_UserRoles_AspNetRoles_RoleId",
                    column: x => x.RoleId,
                    principalTable: "AspNetRoles",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
                table.ForeignKey(
                    name: "FK_UserRoles_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "UserTokens",
            columns: table => new
            {
                UserId = table.Column<int>(type: "int", nullable: false),
                LoginProvider = table.Column<string>(type: "nvarchar(450)", nullable: false),
                Name = table.Column<string>(type: "nvarchar(450)", nullable: false),
                Value = table.Column<string>(type: "nvarchar(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserTokens", x => new { x.UserId, x.LoginProvider, x.Name });
                table.ForeignKey(
                    name: "FK_UserTokens_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateTable(
            name: "UserUser",
            columns: table => new
            {
                TrackedId = table.Column<int>(type: "int", nullable: false),
                TrackersId = table.Column<int>(type: "int", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserUser", x => new { x.TrackedId, x.TrackersId });
                table.ForeignKey(
                    name: "FK_UserUser_Users_TrackedId",
                    column: x => x.TrackedId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
                table.ForeignKey(
                    name: "FK_UserUser_Users_TrackersId",
                    column: x => x.TrackersId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Restrict);
            });

        migrationBuilder.CreateIndex(
            name: "RoleNameIndex",
            table: "AspNetRoles",
            column: "NormalizedName",
            unique: true,
            filter: "[NormalizedName] IS NOT NULL");

        migrationBuilder.CreateIndex(
            name: "IX_GPSData_UserId",
            table: "GPSData",
            column: "UserId");

        migrationBuilder.CreateIndex(
            name: "IX_RoleClaims_RoleId",
            table: "RoleClaims",
            column: "RoleId");

        migrationBuilder.CreateIndex(
            name: "IX_UserClaims_UserId",
            table: "UserClaims",
            column: "UserId");

        migrationBuilder.CreateIndex(
            name: "IX_UserLogins_UserId",
            table: "UserLogins",
            column: "UserId");

        migrationBuilder.CreateIndex(
            name: "IX_UserRoles_RoleId",
            table: "UserRoles",
            column: "RoleId");

        migrationBuilder.CreateIndex(
            name: "EmailIndex",
            table: "Users",
            column: "NormalizedEmail");

        migrationBuilder.CreateIndex(
            name: "UserNameIndex",
            table: "Users",
            column: "NormalizedUserName",
            unique: true,
            filter: "[NormalizedUserName] IS NOT NULL");

        migrationBuilder.CreateIndex(
            name: "IX_UserUser_TrackersId",
            table: "UserUser",
            column: "TrackersId");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropTable(
            name: "GPSData");

        migrationBuilder.DropTable(
            name: "RoleClaims");

        migrationBuilder.DropTable(
            name: "Roles");

        migrationBuilder.DropTable(
            name: "UserClaims");

        migrationBuilder.DropTable(
            name: "UserLogins");

        migrationBuilder.DropTable(
            name: "UserRoles");

        migrationBuilder.DropTable(
            name: "UserTokens");

        migrationBuilder.DropTable(
            name: "UserUser");

        migrationBuilder.DropTable(
            name: "AspNetRoles");

        migrationBuilder.DropTable(
            name: "Users");
    }
}

那么错误在哪里呢？

Answer 1

据我了解，实体框架通常无法检测您的意图何时只是重命名列/表或实际上删除它并创建其他内容，因此它最终会搭建一个删除并重新创建列/表的迁移。

来自文档：

EF Core 通常无法知道何时要删除列并创建新列（两次单独的更改），以及何时应重命名列。如果按原样应用上述迁移，您的所有客户名称都将丢失。要重命名列，请将上面生成的迁移替换为以下内容：

在这种情况下，您应该做的是自定义 EF 自动搭建的迁移代码。在这种情况下，您可以利用这些方法RenameColumn并RenameTable指定在迁移中仅应进行重命名操作。

因此，生成迁移后，删除and方法中的DropandCreate语句，并将其替换为对和 的相应调用。UpDownRenameTableRenameColumn

例如：

public partial class AddedTrackingProperties : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(
            name: "IdentityUserRole", newName: "UserRoles");

       // ...
       // TODO: other necessary rename tables/columns
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(
            name: "UserRoles", newName: "IdentityUserRole");

       // ...
       // TODO: other necessary rename tables/columns
    }
}