c# - EF Core 迁移从新的复合索引中删除第一个外键索引

问题描述

这是我的模型：

public class Period
{
    [Key]
    public int Id { get; set; }
}

public class Company
{
    [Key]
    public int Id { get; set; }
}

public class Invoice
{
    [Key]
    public int Id { get; set; }

    public int PeriodId { get; set; }
    public Period Period { get; set; }

    public int CompanyId { get; set; }
    public Company Company { get; set; }
}

没有什么花哨。一张简单的发票，有一个时期和一个公司。

以下是它们的配置方式：

modelBuilder.Entity<Invoice>()
    .HasOne(p => p.Period)
    .WithMany()
    .OnDelete(DeleteBehavior.Restrict)
;

modelBuilder.Entity<Invoice>()
    .HasOne(p => p.Company)
    .WithMany()
    .OnDelete(DeleteBehavior.Restrict)
;

这是由此生成的迁移文件：

migrationBuilder.CreateTable(
    name: "Companies",
    columns: table => new
    {
        Id = table.Column<int>(nullable: false)
            .Annotation("SqlServer:Identity", "1, 1")
    },
    constraints: table =>
    {
        table.PrimaryKey("PK_Companies", x => x.Id);
    });

migrationBuilder.CreateTable(
    name: "Periods",
    columns: table => new
    {
        Id = table.Column<int>(nullable: false)
            .Annotation("SqlServer:Identity", "1, 1")
    },
    constraints: table =>
    {
        table.PrimaryKey("PK_Periods", x => x.Id);
    });

migrationBuilder.CreateTable(
    name: "Invoices",
    columns: table => new
    {
        Id = table.Column<int>(nullable: false)
            .Annotation("SqlServer:Identity", "1, 1"),
        PeriodId = table.Column<int>(nullable: false),
        CompanyId = table.Column<int>(nullable: false)
    },
    constraints: table =>
    {
        table.PrimaryKey("PK_Invoices", x => x.Id);
        table.ForeignKey(
            name: "FK_Invoices_Companies_CompanyId",
            column: x => x.CompanyId,
            principalTable: "Companies",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
        table.ForeignKey(
            name: "FK_Invoices_Periods_PeriodId",
            column: x => x.PeriodId,
            principalTable: "Periods",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    });

migrationBuilder.CreateIndex(
    name: "IX_Invoices_CompanyId",
    table: "Invoices",
    column: "CompanyId");

migrationBuilder.CreateIndex(
    name: "IX_Invoices_PeriodId",
    table: "Invoices",
    column: "PeriodId");

一切似乎都是合法的。现在我需要创建一个唯一索引来控制公司发票在一段时间内的唯一性：

modelBuilder.Entity<Invoice>()
    .HasIndex(p => new
    {
        p.PeriodId,
        p.CompanyId,
    })
    .IsUnique()
;

这就是迁移现在的样子：

migrationBuilder.DropIndex(
    name: "IX_Invoices_PeriodId",
    table: "Invoices");

migrationBuilder.CreateIndex(
    name: "IX_Invoices_PeriodId_CompanyId",
    table: "Invoices",
    columns: new[] { "PeriodId", "CompanyId" },
    unique: true);

注意“DropIndex”。它从我的复合索引中获取第一列。如果我更改顺序，它仍然会删除第一个：

modelBuilder.Entity<Invoice>()
    .HasIndex(p => new
    {
        p.CompanyId,
        p.PeriodId,
    })
    .IsUnique()
;

migrationBuilder.DropIndex(
    name: "IX_Invoices_CompanyId",
    table: "Invoices");

migrationBuilder.CreateIndex(
    name: "IX_Invoices_CompanyId_PeriodId",
    table: "Invoices",
    columns: new[] { "CompanyId", "PeriodId" },
    unique: true);

我不确定我是否理解这背后的逻辑。复合索引中是否有什么特别之处使单独的索引无用？或者它可能是某种错误？

我发现这个问题的唯一提及是关于 SO 的帖子有点过时： EF Migrations drops index when added compsite index

PS 使用 SQL Server 作为数据库提供程序在 3.1.8 上测试。

标签： c#entity-framework-coreforeign-keysrelational-databaseentity-framework-migrations

c# - EF Core 迁移从新的复合索引中删除第一个外键索引

问题描述

解决方案

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