EF核心迁移 - 添加带有唯一索引的新列现有数据库

发布于 2025-01-30 11:09:19 字数 830 浏览 4 评论 0原文

我有一个带有数据的现有表，我想在其中添加一个新列。

我必须为列设置默认值，但是当我执行迁移时，它会抱怨它。如果我不设置默认值，它也会抱怨，因为所有值都是null，这也不是唯一的。

错误：

创建唯一索引语句终止了，因为重复键找到了对象名称“ powder.powderbox”和索引名称 'ix_powderbox_code'。重复的密钥值是（...）。

配置

builder.Property(x => x.Code)
       .IsRequired()
       .HasMaxLength(14);

builder
   HasIndex(x => x.Code)
   IsUnique();

迁移：

migrationBuilder.AddColumn<string>(
   name: "Code",
   schema: "powder",
   table: "PowderBox",
   type: "nvarchar(14)",
   maxLength: 14,
   nullable: false,
   defaultValue: "...";

migrationBuilder.CreateIndex(
   name: "IX_PowderBox_Code",
   schema: "powder",
   table: "PowderBox",
   column: "Code",
   unique: true);

如何在具有唯一索引的现有表中添加新列？

原文

I have an existing table with data and I want to add a new column to it.

I have to set a default value for the column, but its complaining about it when I execute my migration. If I do not set a default value, it will also complain because all the values are null, which is also not unique.

Error:

The CREATE UNIQUE INDEX statement terminated because a duplicate key
was found for the object name 'powder.PowderBox' and the index name
'IX_PowderBox_Code'. The duplicate key value is (...).

Configuration

builder.Property(x => x.Code)
       .IsRequired()
       .HasMaxLength(14);

builder
   HasIndex(x => x.Code)
   IsUnique();

Migrations:

migrationBuilder.AddColumn<string>(
   name: "Code",
   schema: "powder",
   table: "PowderBox",
   type: "nvarchar(14)",
   maxLength: 14,
   nullable: false,
   defaultValue: "...";

migrationBuilder.CreateIndex(
   name: "IX_PowderBox_Code",
   schema: "powder",
   table: "PowderBox",
   column: "Code",
   unique: true);

How can I add a new column to an existing table with a unique index?

分享到QQ

分享到微博