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Tomáš Herceg "Entity Framework Core 2.1 – what’s new?"
The document discusses the key differences between Entity Framework 6 and Entity Framework Core, highlighting that EF Core is a lightweight, extensible, and cross-platform implementation with several new features introduced in version 2.1, such as data seeding, lazy loading, entity constructors with parameters, value conversions, and improved group by translation. It provides insights into the advantages and disadvantages of using EF Core, including its speed for simple cases and support for mapping features, while acknowledging some limitations in handling complex queries. Future plans include the introduction of a Cosmos DB provider in version 2.2.
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Similar to Tomáš Herceg "Entity Framework Core 2.1 – what’s new?"
Tomáš Herceg "Entity Framework Core 2.1 – what’s new?"
- 1. Tomas Herceg Microsoft MVP MicrosoftRegional Directory @hercegtomas https://www.tomasherceg.com/blog Entity Framework Core 2.1 – what’s new?
- 2. Difference between EF6 and EF Core ▪ Entity Framework 6 ▪ Old codebase ▪ Difficult to extend ▪ Lot of legacy API included for compatibility ▪ ObjectContext ▪ DbContext ▪ High memory footprint
- 3. Difference between EF6 and EF Core ▪ Entity Framework Core ▪ New implementation ▪ Lightweight ▪ Extensible ▪ Cross-platform (.NET Standard) ▪ Support of non-relational data stores ▪ Current state ▪ Some features of EF 6 missing ▪ Lot of new features not present in EF 6 ▪ 2.0 stable, 2.1 preview 2
- 4. New Features inEF Core 2.1 ▪ Data Seeding ▪ Lazy loading ▪ Parameters in entity constructors ▪ Value conversions ▪ GROUP BY translation ▪ and more… ▪ https://docs.microsoft.com/en-us/ef/core/what-is-new/ef-core-2.1
- 5. Data Seeding ▪ Neverreally solved in EF 6 ▪ EF Migrations with SQL(@”INSERT INTO …”) ▪ table.AddOrUpdate in Migrations configuration ▪ Someone just gave up ▪ No solution in EF Core until 2.1 ▪ Data are part of model definition ▪ Migrations are aware of data
- 6. DEMO Data Seeding Tomas Herceg MicrosoftMVP Microsoft Regional Directory @hercegtomas https://www.tomasherceg.com/blog
- 7. Lazy loading ▪ Loved& hated in EF 6 ▪ Eager loading ▪ context.Blogs .Include(blog =>blog.Posts) .ThenInclude(post => post.Comments) ▪ Explicit loading ▪ context.Entry(blog) .Collection(blog => blog.Posts) .Load() ▪ Projection ▪ query.Select(blog => new { … })
- 8. Lazy loading ▪ Mustbe turned on explicitly ▪ With proxies (easiest one) ▪ Separate NuGet package ▪ Microsoft.EntityFrameworkCore.Proxies ▪ Call UseLazyLoadingProxies() ▪ Without proxies ▪ Inject ILazyLoader or Action<object, string> in constructor
- 9. DEMO Lazy loading Tomas Herceg MicrosoftMVP Microsoft Regional Directory @hercegtomas https://www.tomasherceg.com/blog
- 10. Entities with constructorparameters ▪ Initialize entity properties with constructor ▪ Bound by naming convention ▪ firstName parameter FirstName property ▪ Supports injecting of other services ▪ DbContext (ohh, ugly) ▪ ILazyLoader / Action<object, string> ▪ IEntityType (EF Core metadata about the entity type)
- 11. DEMO Entity constructor parameters TomasHerceg Microsoft MVP Microsoft Regional Directory @hercegtomas https://www.tomasherceg.com/blog
- 12. Value conversions ▪ Databasetypes are mapped to .NET types ▪ Conversions were hard-coded in EF 6 ▪ EF Core adds extensibility ▪ Many built-in converters ▪ BoolToZeroOneConverter and more ▪ BytesToStringConverter (base64) ▪ EnumToStringConverter ▪ TimeSpanToTicksConverter ▪ …
- 13. DEMO Value conversions Tomas Herceg MicrosoftMVP Microsoft Regional Directory @hercegtomas https://www.tomasherceg.com/blog
- 14. GROUP BY translation ▪GROUP BY was evaluated in-memory until EF Core 2.1 ▪ Huge issue ▪ Some limitations still remain ▪ Always check generated SQL
- 15. DEMO GROUP BY translation TomasHerceg Microsoft MVP Microsoft Regional Directory @hercegtomas https://www.tomasherceg.com/blog
- 16. Is it readyyet? ▪ Well, it depends... ▪ Advantages ▪ Offers more mapping features ▪ Supports .NET Core ▪ Faster for simple cases ▪ Easy fall back to raw SQL ▪ Disadvantages ▪ No support for complex queries
- 17. Future plans ▪ Productplanning for 2.2 not ready yet ▪ Follow the GitHub repo ▪ https://github.com/aspnet/EntityFrameworkCore ▪ Cosmos DB provider ▪ Planned for 2.2 ▪ Document DB API ▪ First large non-relational provider
- 18. Tomas Herceg Microsoft MVP MicrosoftRegional Directory @hercegtomas https://www.tomasherceg.com/blog Q&A