Question

我想将ASP.Net core 2.2中模型的主键的数据类型从int更改为long，因为它即将超出int范围。该应用程序先执行代码，然后使用SQL Server作为数据库。

更改模型中的数据类型也可以运行“添加迁移”，但是Update-Database失败，并显示以下错误：

System.Data.SqlClient.SqlException (0x80131904): The index 'IX_tblMTransactions_OriginalTransactionId' is dependent on column 'OriginalTransactionId'.
The object 'FK_tblMTransactions_tblMTransactions_OriginalTransactionId' is dependent on column 'OriginalTransactionId'.

所以我读到它，似乎需要对迁移进行一些调整，例如在更改列之前先删除外键和索引，然后再将它们放回原处。不幸的是，我在.net core 2.2中找不到有关执行此操作的任何有用信息，我找到的最接近的信息是this question，但它谈到了.net core 2.1以及选项DropForeignKey和{{1} } 提到this article ，. net core 2.2似乎不再可用。

这是迁移类：

DropIndex

这是该表的列，键和索引的屏幕截图：

有人知道如何在.NET Core 2.2中调整迁移类以使其正常工作吗？

谢谢

Answer 1

感谢Ivan Stoev，我找到了解决方案。我必须像这样手动添加索引和键的删除和创建：

public partial class _20190817_2317 : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropForeignKey(
            name: "FK_tblMTransactions_tblMTransactions_OriginalTransactionId",
            table: "tblMTransactions");

        migrationBuilder.DropIndex(
            name: "IX_tblMTransactions_OriginalTransactionId",
            table: "tblMTransactions");

        migrationBuilder.DropPrimaryKey(
            name: "PK_tblMTransactions",
            table: "tblMTransactions");

        migrationBuilder.AlterColumn<long>(
            name: "OriginalTransactionId",
            table: "tblMTransactions",
            nullable: true,
            oldClrType: typeof(int),
            oldNullable: true);

        migrationBuilder.AlterColumn<long>(
            name: "Id",
            table: "tblMTransactions",
            nullable: false,
            oldClrType: typeof(int))
            .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn)
            .OldAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);

        migrationBuilder.AddPrimaryKey(
            name: "PK_tblMTransactions",
            table: "tblMTransactions",
            column: "Id");

        migrationBuilder.CreateIndex(
            name: "IX_tblMTransactions_OriginalTransactionId",
            table: "tblMTransactions",
            column: "OriginalTransactionId");

        migrationBuilder.AddForeignKey(
            name: "FK_tblMTransactions_tblMTransactions_OriginalTransactionId",
            table: "tblMTransactions",
            column: "OriginalTransactionId",
            principalTable: "tblMTransactions",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.AlterColumn<int>(
            name: "OriginalTransactionId",
            table: "tblMTransactions",
            nullable: true,
            oldClrType: typeof(long),
            oldNullable: true);

        migrationBuilder.AlterColumn<int>(
            name: "Id",
            table: "tblMTransactions",
            nullable: false,
            oldClrType: typeof(long))
            .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn)
            .OldAnnotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn);
    }
}

再次感谢，伊万！

在.net Core 2.2模型中将数据类型的数据类型从int更改为long属性

1 个答案: