c# - 在 Entity Framework Core 中创建非聚集索引

Question

使用Entity Framework Core，想来个Guid PK，不苦页fragmentation在数据库中。

我看过这个post和 this .虽然这在 EF6 中是可能的，但它的完成方式似乎已经改变。

是否可以在 Entity Framework Core 中创建一个非集群主键并有一个额外的索引？

下面的问答。

Answer 1

可以使用 EntityFrameworkCore v1.0.1 或更高版本。

下面的代码得到了想要的结果:

using System;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;

namespace TestApplication.Models
{

    /// <summary>
    /// The context class. Make your migrations from this point.
    /// </summary>
    public partial class TestApplicationContext : DbContext
    {
        public virtual DbSet<Company> Companies { get; set; }

        public TestApplicationContext(DbContextOptions<TestApplicationContext> options) : base(options)
        {

        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            // standard stuff here...
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Company>(entity =>
            {
                entity.Property<Guid>("CompanyId")
                        .ValueGeneratedOnAdd();

                entity.Property<int>("CompanyIndex")
                        .UseSqlServerIdentityColumn()
                        .ValueGeneratedOnAdd();

                entity.Property(e => e.CompanyName)
                    .IsRequired()
                    .HasColumnType("varchar(100)");

                // ... Add props here.

                entity.HasKey(e => e.CompanyId)
                    .ForSqlServerIsClustered(false)
                    .HasName("PK_Company");
                entity.HasIndex(e => e.CompanyIndex)
                    .ForSqlServerIsClustered(true)
                    .HasName("IX_Company");
            });
        }
    }

        /// <summary>
        /// The model - put here for brevity.
        /// </summary>
        public partial class Company
        {
            public Company()
            {
            }

            public Guid CompanyId { get; set; }
            public int CompanyIndex { get; set; }

            public string CompanyName { get; set; }
            // more props here.
        }

    }

项目.json

{
    "version": "1.0.0-*",

    "dependencies": {
        "Microsoft.EntityFrameworkCore.Design": "1.0.1",
        "Microsoft.EntityFrameworkCore.SqlServer": "1.0.1",
        "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.0.1",
        "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview3-final",
        "NETStandard.Library": "1.6.0"
    },
    "tools": {
        "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview3-final",
        "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
    },
    "frameworks": {
        "netstandard1.6": {
            "imports": "dnxcore50"
        }
    }
}