1. A Tour of EF Core’s Most Interesting & Important Features
Julie Lerman @julielerman about.me/julielerman

2. “Entity Framework (EF) Core is a lightweight and extensible version of the popular Entity Framework data access technology.”
EF Core Documentation

3. EF 6.x
EF Core

4. github.com/aspnet/entityframework
docs.efproject.net

5. Modern Software Practices
.NET Core Themes
Composable APIs
Cross-Platform
Modern Software Practices

6. Highlights of EF Core
Began life as “EF7” 1.0 RTM June 27, 2016 Lightweight, Composable version of EF Performance, generated SQL, runtime model building & etc More flexible logging (ILoggerProvider) Integrates with ASP.NET Core Windows, X-Plat with .NET Core, UWP, Xamarin Lots of new features

7. Coming from EF6?
Not replacing, nor an update to, EF6.x Total re-write, not backwards compatible Drops EDMX, ObjectContext Many familiar APIs: DbContext, Change Tracker, Migrations, LINQ

8. have to re-learn everything
You do not
have to re-learn everything

9. But… it’s still new
& different

10. COMMON INFRASTRUCTURE
9/9/2018 1:37 AM
Unified platform
.NET FRAMEWORK
WINDOWS APPLICATIONS
.NET CORE
CROSS-PLATFORM SERVICES
MOBILE APPLICATIONS
XAMARIN
TOOLS
Visual Studio
Visual Studio Code
.NET STANDARD LIBRARY
COMMON INFRASTRUCTURE
Xamarin Studio
Compilers
Languages
Runtime components
EF6.x
EF Core
© 2014 Microsoft Corporation. All rights reserved. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

11. Where Can You Use EF Core?
.NET
.NET Core
UWP
Windows
Windows, macOS, Linux
Windows 10 OS
Any .NET Console
WinForms
WPF
ASP.NET 4
etc..
ASP.NET Core Web Apps & APIs
Libraries
Services
Console Apps
Mobile PC
HoloLens
Xbox
Surface Hub
IoT Devices
App Types
EF Core runs in .NET core and .NET core runs in a LOT of places! Inside of the full .NET Framework (that is any version from and newer, or on the more limited .NET Core which is the runtime that can run natively not only on windows but also on Mac and linux and also on another limited version of .NET which is the Universal Windows Platform for Windows 10.
That doesn’t necessarily mean that you *should* use EF core in all of these scenarios. And this is a really important point

12. EF6 Features vs EF Core Features
New
EF Core 1.0.0
EF Core >1.1.0
EF6 Feature Set
EF Core 1.1.0
Limited Parity
EF Core 1.0.0
Never coming to EF Core

13. bit.ly/efcoreroadmap Implemented (1.0) In Progress (1.1) Backlog
 ”EF6.x continues to be the best version of EF for a number of applications until these features are implemented”
Implemented (1.0)
In Progress (1.1)
Backlog
Critical O/RM
The things we think we need before we say
EF Core is the recommended version of EF.
High priority features
Many features on our backlog High priority but we think EF Core would be a compelling release
for the vast majority of applications without them

14. EF Core 1.1 (Preview is Here! RTM Late Q4 2016)
Bug fixing to improve stability
Critical O/RM features
Removing adoption blockers
Improved LINQ translation
DbSet.Find
Explicit Loading
More EntityEntry APIs:
Reload, GetModifiedProperties, GetDatabaseValues etc.
Connection resiliency
Parity with EF6.x
Mapping to fields for scalar properties*
SQL Server memory-optimized table support
Simplified service replacement
New Capabilities

15. EF Core Enables Long-Requested Features
Batch Insert, Update, Delete
Unique Constraints
Smarter Queries
Smarter Disconnected Patterns
In-Memory Provider for Testing
Extensible & IoC Friendly
Model-Only Properties (“Shadow State”)
Smarter & Simpler Mapping
But these changes will enable EF to solve problems that we’ve been asking of EF for a long time. The existing code base hindered the EF team from achieving many of these features but some are already in the 1.0 version of EF Core and more have been added to upcoming releases and even more are planned for future releases of EF Core. Some examples of features that we’ve already gained with EF Core are the ability to
[CLICK] do batch insert, updates and deletes – something that has never been supported in EF although some community members have created extensions to give us that behavior in the meantime.
[CLICK]We’ll can specify unique foreign keys in entities …another feature that we’ve been asking for since the first version.
[CLICK]LINQ queries have become smarter ..one way EF Core enables this is to allow providers to pick and choose which parts of a query will get convereted to TSQL and which will be executed in memory. This allows us to use inline functions in our queries and also to compose LINQ methods on top of raw sql and the composed query be fully executed on the server.
[CLICK] Disconnecte entities and graphs have always been troublesome. The team has created patterns to make it easier to work with entities and graphs in disconnected apps as well as to provide consistent behavior.
[CLICK]Thanks to the new flexibility for providers, the team was able to create an in-memory provider that makes it really easy to build automated tests against EF code that don’t need to hit the database. This remains one of my favorite features!
[CLICK]We’ve also asked Microsoft to make Entity framework more extensible and EF Core is designed to be easy to use Inversion of Control patterns and dependency injection and it integrates with ASPNET Core’s service provider functionality.
[CLICK]. A source of frustration for many developers was that we could not completely hide a property in domain classes because EF could not materialize fields, only properties. EF Core is now able to populate backing fields. This is another new feature that I’m particularly fond of!
[CLICK] Among improvements to EF’s mapping are capabilities such as smarter and simpler ways to create one to one and to express relationships.
If you go to data.uservoice.com, focusing on the entityframework requests you can see that many of the points I just highlighted have been on the list for a long time. You can also see notes that work has been started or is being planned to attack these long requested features.
In later modules of this course, I’ll show you examples of these features in action.
EF Core 1.1
Mapping to Backing Fields
Opt out of DB Transactions at SaveChanges
Temporary Properties for run time, not DB
Simple Service Replacement

16. Next After EF Core 1.1 Parity with EF6.x New Capabilities
Complex/value types
Visual Studio wizard for reverse engineering
Mapping to fields for navigation properties
Simple type conversions
New Capabilities

17. Composable is not just about Nuget packages
EF is made up of 100’s of services
Service i.e. class that has a single responsibility
Detecting changes to an object since it was pulled from the database
Taking a particular part of a linq query and translating it to sql
Reuse a piece of EF
Rowan uses type mapper as an example: var mapper=_context.GetService<IRelationalTypeMapper>
Replace/tweak a piece of EF (1.1)
protected internal override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
=> optionsBuilder
.ReplaceService<IModelCustomizer, CustomModelCustomizer>()
.UseInMemoryDatabase();

18. My Picks To Share Change Tracker Familiar/Different In Memory Provider
Migrations Enhancements
Cross- Platform via .NET Core
Logging
Seed from JSON
ASP.NET Core Integration
Demos of field mapping, use EF services directly, replacing services, SQL Server Memory optimized table in Rowan M OnDotNet Demos of improved SQL generation, performance improvements,, targeting multiple databases in Rowan Miller Ignite video

19. Resources
Demos are at
Rowan Miller (EF Program Mgr) - Entity Framework Core 
Rowan Miller - Access data in .NET Core 1.0 with Entity Framework
Pluralsight: Play by Play : EF Core First Look (bit.ly/PS_EFCoreLook)
Coming soon: Getting Started with EF Core
EF Docs: docs.efproject.net EFCore: github.com/aspnet/entityframework
Arthur Vickers (team) blog: blog.oneunicorn.com
Roadmap: bit.ly/efcoreroadmap
MSDN Mag Data Points articles: bit.ly/datapointscolumn

20. @julielerman about.me/julielerman