在.NET Core 3中找不到dotnet ef

编程入门行业动态更新时间:2024-10-21 18:59:43

本文介绍了在.NET Core 3中找不到dotnet ef的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

我正在关注文档以创建初始迁移。当我执行 dotnet 时，我得到了帮助部分，这意味着PATH可以正常工作。

I'm following the docs in order to create an initial migration. When I execute dotnet, I get the help section, meaning that the PATH works properly.

然后我尝试从控制台窗口的文档中执行以下命令：

Then I try to execute the command below from the docs in console window:

dotnet ef migrations add InitialCreate

我收到以下错误：

Could not execute because the specified command or file was not found. Possible reasons for this include: * You misspelled a built-in dotnet command. * You intended to execute a .NET Core program, but dotnet-ef does not exist. * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.

自从复制命令以来，我排除了第一项。
我排除了第二项，因为安装了软件包 Microsoft.EntityFrameworkCore.SqlServer 。
我排除了第三项，因为我得到了

我正在谷歌搜索问题，但是由于该版本是新版本，因此没有太多工作要做，并且/或者它淹没了较早版本中的类似问题。

I'm googling the issue but since the version is new, there's not much to go on and/or it's drowning in similar issues from earlier versions.

我试图强行安装 Microsoft .EntityFrameworkCore ，以防需要显式添加。我遇到错误消息，告诉我要选择的最新版本是2.2.6，降级是不行的。我不确定如何安装与我的系统上已有的SQL软件包兼容的版本（甚至无法确定这是否是解决此问题的正确方法）。

I tried to forcibly install Microsoft.EntityFrameworkCore just in case it needs to be explicitly added. I ran into the error message telling me that the latest version to pick from is 2.2.6 and a downgrade is a no-go. I'm not sure how to install the version compatible with the SQL-package I have on my system already (and even less certain if that's right approach to kill this issue).

检测到的包降级：Microsoft.EntityFrameworkCore从3.0.0-preview6.19304.10降为2.2.6。直接从项目中引用该软件包以选择其他版本。 Web-> Microsoft.EntityFrameworkCore.SqlServer 3.0.0-preview6.19304.10-> Microsoft.EntityFrameworkCore.Relational 3.0.0-preview6.19304.10-> Microsoft.EntityFrameworkCore（> = 3.0.0-preview6.19304.10） Web-> Microsoft.EntityFrameworkCore（ > = 2.2.6）

Detected package downgrade: Microsoft.EntityFrameworkCore from 3.0.0-preview6.19304.10 to 2.2.6. Reference the package directly from the project to select a different version. Web -> Microsoft.EntityFrameworkCore.SqlServer 3.0.0-preview6.19304.10 -> Microsoft.EntityFrameworkCore.Relational 3.0.0-preview6.19304.10 -> Microsoft.EntityFrameworkCore (>= 3.0.0-preview6.19304.10) Web -> Microsoft.EntityFrameworkCore (>= 2.2.6)

请参见公告不再是内置的，并且需要显式安装：

See the announcement for ASP.NET Core 3 Preview 4, which explains that this tool is no longer built-in and requires an explicit install:

此更改使我们可以将 dotnet ef 作为常规.NET CLI工具发布，可以将其安装为全局或全局本地工具。例如，为了能够管理迁移或搭建 DbContext ，请安装 dotnet ef 作为全局工具，键入以下内容命令： The dotnet ef tool is no longer part of the .NET Core SDK

This change allows us to ship dotnet ef as a regular .NET CLI tool that can be installed as either a global or local tool. For example, to be able to manage migrations or scaffold a DbContext, install dotnet ef as a global tool typing the following command:

更改的原因在文档：

此更改使我们可以在NuGet上作为常规.NET CLI工具分发和更新 dotnet ef ，这与EF Core 3.0也始终以NuGet软件包的形式分发。 Why

This change allows us to distribute and update dotnet ef as a regular .NET CLI tool on NuGet, consistent with the fact that the EF Core 3.0 is also always distributed as a NuGet package.

此外，您可能需要在项目中添加以下NuGet软件包：

In addition, you might need to add the following NuGet packages to your project: