Entity Framework Core 1.x/2.x Advanced
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Entity Framework Core is Microsoft's modern object-database mapper for .NET. It is smaller and more lightweight than the original Entity Framework, supports multiple platforms beyond Windows, and is architecture-independent of relational databases. The document highlights several key features of EF Core such as code first modeling, logging, context pooling, model definition, shadow properties, query filtering, keyless entity types, migrations, relationships like inheritance and references, and support for NoSQL databases like Azure Cosmos DB. Questions are welcomed from attendees about using EF Core for their applications and projects.
Entity Framework Core 1.x/2.x Advanced
- 1. Entity Framework Core 1.x/2.x Advanced Christian Nagel https://csharp.christiannagel.com
- 2. Topics Entity Framework .vs. EF Core Essential Features nicht in Entity Framework Viele, viele Code Samples
- 3. Christian Nagel • Training • Coaching • Consulting • Development • Microsoft MVP • www.cninnovation.com • csharp.christiannagel.com
- 4. Intro
- 5. Compare Entity Framework • Long History • Legacy Code • Windows only • Big • Conventions and "Magic" • Relational Databases only Entity Framework Core • New Code (.NET Core 1.0) • Modern Patterns • Multi-Platform • Smaller Footprint • Conventions, no "Magic" • Architecture independent of relational databases
- 6. Code First – only! Database first, Model first not supported You still can create a model from a database dotnet ef scaffold
- 7. Logging • .NET Core Logging • ILogger, ILoggerFactory • Add Query Tags (2.2) • Samples: BooksSample, LazyLoading
- 8. DbContext Pools (2.0) • Connection Strings are pooled • Creating context can take time • DbContexts can be pooled • AddDbContextPool() • It's just a matter of container configuration • No change in using the context • Sample: ContextPoolSample
- 10. Model Definition • Convention • Annotations (Attributes) • Fluent API • Separate configuration type with IEntityTypeConfiguration<T>
- 11. Shadow Properties (1.0) • Are not represented in the model • Available in database tables • Can be accessed using the context • Example Columns • IsDeleted • LastUpdated • TenantId • Sample App: BooksSample
- 12. Model-Level Query Filter • Define a filter that is included with every query • Example: IsDeleted, TenantId • Sample App: BooksSample
- 13. Mapping to Fields (1.1) • Read-only Properties in the model • Private fields • Not accessible via Properties • Constructors with parameters (2.1) • Sample App: BooksSample
- 14. Keyless Entity Types (2.1) • Kwown as query types before 3.0 • HasNoKey() Fluent API • Mapped via ToTable() or ToView()
- 15. Migrations • Manage the database from code • Add migrations for every change • Includes scaffolding of data • Migrate: • context.Database.Migrate() • dotnet ef database update • dotnet ef migrations script • Sample App: MigrationsConsoleApp, MigrationsLib
- 16. Relations
- 17. Table per Hierarchy (TPH) - Inheritance • One table per hierarchy • Conventions • Base classes and derived classes • All types DbSet<T> mapped • Fluent API • Only abstract base class DbSet<T> mapped • HasDiscriminator • HasValue • Sample: TPHWithConventions / TPHWithFluentAPI
- 18. Table Splitting (2.0) • Multiple types access the same table • Menu & MenuDetail types in one table • Fluent API • HasOne().WithOne().HasForeignKey() • Sample: TableSplitting
- 19. Owned Entities (2.0) • Owned entities are part of the owner • Owned attribute (2.1) • Fluent API • OwnsOne – define relation • Sample: OwnedEntities
- 20. References • Eager Loading • Include relations with a query • Include() / ThenInclude() • Explicit Loading • Load relations on request • EntityEntry.Reference().Load • EntityEntry.Collection().Load • Lazy Loading (2.2) • Load on property access
- 21. Lazy Loading (2.2) • This feature needs to be explicitly enabled • NuGet Package Microsoft.EntityFrameworkCore.Proxies • UseLazyLoadingProxies() with options • Virtual Properties are required in the model • Sample: LazyLoading
- 22. NoSQL
- 23. Azure Cosmos DB NoSQL Document Database Supported by EF Core 3.0 Use one or multiple containers for entities Create hierarchies of data in one JSON document: OwnsOne / OwnsMany
- 24. Summary EF Core is ready to use Multi-Platform, Modern Patterns Great Features Relational and NoSQL Provider
- 25. Questions?
- 27. Thank you!