Question

我试图找出如何首先通过Entity Framework代码向sql server中的数据表添加Timestamp / rowversion列。

这是使用EF Core V2.0。

我尝试了两种方法来实现这一目标，第一种方法;

 public class Contact
{

    public int ContactId { get; set; }

    public string ContactName { get; set; }

    public string CompanyName { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    [Timestamp]
    public byte[] RowVersion { get; set; }
}

第二个通过流利的api

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        foreach (var entityType in modelBuilder.Model.GetEntityTypes())
        {
            modelBuilder.Entity(entityType.Name).Property<DateTime>("Inserted");
            modelBuilder.Entity(entityType.Name).Property<DateTime>("LastModified");
            modelBuilder.Entity(entityType.Name).Property<byte[]>("RowVersion");

        }
    }

在我运行Add-Migration后的两种情况下，我得到以下内容;

       protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.CreateTable(
            name: "Contacts",
            columns: table => new
            {
                ContactId = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
                CompanyName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                ContactName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                FirstName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                Inserted = table.Column<DateTime>(type: "datetime2", nullable: false),
                LastModified = table.Column<DateTime>(type: "datetime2", nullable: false),
                LastName = table.Column<string>(type: "nvarchar(max)", nullable: true),
                RowVersion = table.Column<byte[]>(type: "varbinary(max)", nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Contacts", x => x.ContactId);
            });
    }

我原以为RowVersion列的类型为timestamp，其可空属性为false。这是EF Core的限制还是我试图做错了？

Answer 1

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<MyEntity>()
      .Property(b => b.MyVersionProperty)
      .IsRowVersion();
}

带EF Core的TimeStamp / Rowversion列

1 个答案: