Пакет "Microsoft.EntityFrameworkCore.Tools.DotNet 2.0.3" имеет тип пакета "DotnetCliTool", который не поддерживается проектом "SportsStore".					

<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <ApplicationIcon />
    <OutputType>Exe</OutputType>
    <StartupObject />
  </PropertyGroup>

  <ItemGroup>
    <Folder Include="wwwroot\" />
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.1.2" PrivateAssets="All" />
    <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.1.9" />
	  <PackageReference Include="Microsoft.AspNetCore.All" />
	  <DotNetCliToolReference Include="Мicrosoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" />
  </ItemGroup>

</Project>

<PackageReference Include="Microsoft.AspNetCore.All" />
	  <DotNetCliToolReference Include="Мicrosoft.EntityFrameworkCore.Tools.DotNet" Version="2.0.0" />

<PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="2.1.1" />
<DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.Dotnet" Version="2.0.0-preview2-final" />

L:\C#\SportsStore>dotnet ef migrations add Initial
Не удалось выполнить, так как не найдены указанная команда или указанный файл.
Возможные причины:
  * Вы неправильно набрали встроенную команду dotnet.
  * Вы планировали выполнить программу .NET Core, однако dotnet-ef не существует.
  * Вы хотели запустить глобальное средство, но по указанному в PATH пути не удалось найти исполняемый файл с префиксом dotnet, имеющий такое имя.

The EF Core tools version '2.1.1-rtm-30846' is older than that of the runtime '2.1.11-servicing-32099'. Update the tools for the latest features and bug fixes.

<ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="2.1.1" />
</ItemGroup>

Обнаружены недопустимые данные при декодировании.

The EF Core tools version '2.1.1-rtm-30846' is older than that of the runtime '2.1.11-servicing-32099'. Update the tools for the latest features and bug fixes

The EF Core tools version '2.1.1-rtm-30846' is older than that of the runtime '2.1.11-servicing-32099'. Update the tools for the latest features and bug fixes

Connection Timeout Expired.  The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement.  This could be because the pre-login handshake failed or the server was unable to respond back in time.  The duration spent while attempting to connect to this server was - [Pre-Login] initialization=158328; handshake=104;

Failed executing DbCommand (219ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
CREATE TABLE [Products] (
    [ProductID] int NOT NULL IDENTITY,
    [Name] nvarchar(max) NULL,
    [Description] nvarchar(max) NULL,
    [Price] int NOT NULL,
    [Category] nvarchar(max) NULL,
    CONSTRAINT [PK_Products] PRIMARY KEY ([ProductID])
);

There is already an object named 'Products' in the database.

{
  "Data": {
    "SportStoreProducts": {
      "ConnectionString": "Server=(localdb)\\MSSQLLocalDB;Database=SportsStore;Trusted_Connection=True;MultipleActiveResultSets=true"
      }
  }
}