Can I use Entity Framework 6 (not core) in .net core?
UPDATE: Yes, EF6 has been cross-platform since version 6.3. https://devblogs.microsoft.com/dotnet/announcing-ef-core-3-0-and-ef-6-3-general-availability/#what-s-new-in-ef-6-3
ORIGINAL ANSWER THAT IS NOW INVALID: No, you can not directly, because EF6 doesn't support .NET Core. But, you can create another project, that compiles against full .NET framework and use it as a reference.
MS has actually made a decent tutorial for this: https://docs.microsoft.com/en-us/aspnet/core/data/entity-framework-6#reference-full-framework-and-ef6-in-the-asp-net-core-project
Update
You can now use EF 6.3 with .NET Core 3.0:
https://devblogs.microsoft.com/dotnet/announcing-ef-core-3-0-and-ef-6-3-general-availability/#what-s-new-in-ef-6-3
Below is an excerpt. However, EF Core has come a long way these days and it's worth giving it another go before going back to something that's reaching end-of-life soon. Specifically for your issue, EF Core supports mapping to spatial data types using the NetTopologySuite spatial library since version 2.2.
What’s new in EF 6.3
Support for .NET Core 3.0
The EntityFramework package now targets .NET Standard 2.1 in addition to .NET Framework 4.x.
This means that EF 6.3 is cross-platform and supported on other operating systems besides Windows, like Linux and macOS.
The migrations commands have been rewritten to execute out of process and work with SDK-style projects.
Support for SQL Server HierarchyId.
Improved compatibility with Roslyn and NuGet PackageReference.
Added ef6.exe utility for enabling, adding, scripting, and applying migrations from assemblies. This replaces migrate.exe. There are certain limitations when using EF 6.3 in .NET Core. For example:
Data providers need to be also ported to .NET Core. We only ported the SQL Server provider, which is included in the EF 6.3 package.
Spatial support won’t be enabled with SQL Server because the spatial types aren’t enabled to work with .NET Core.
Note that this limitation applies to EF 6.3 but not to EF Core 3.0. The latter continues to support spatial using the NetTopologySuite library.
There’s currently no support for using the EF designer directly on .NET Core or .NET Standard projects.
Original Answer
It isn’t ready yet, but starting with .NET Core 3.0, you will be able to.
https://blogs.msdn.microsoft.com/dotnet/2018/05/07/net-core-3-and-support-for-windows-desktop-applications/
Similarly, EF6 will be updated to work on .NET Core 3.0, to provide a simple path forward for existing applications using EF6.
https://youtu.be/GN54OV5cCBM?t=1146
But there's also EF6, which we've already announced is going to be ported to work on .NET Core...
UPDATE: Yes, EF6 has been cross-platform since version 6.3. https://devblogs.microsoft.com/dotnet/announcing-ef-core-3-0-and-ef-6-3-general-availability/#what-s-new-in-ef-6-3
ORIGINAL ANSWER THAT IS NOW INVALID: Like @Niko said, you cannot directly with EF6 but there is a fork that allows it.
Disclaimer: I'm the owner of the project Entity Framework Classic
Entity Framework Classic is an EF6 fork. It's everything you like about EF6, but with better performance, must-have features, .NET Core support, and more.
There is a FREE Community version that includes pretty much everything and an Enterprise version that include additional features.