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Learn Entity Framework Core 5
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Learn Entity Framework Core 5
Introduction of Entity Framework Core
What's New in EF Core 5
Simple Logging
Filtered Included
Backing Fields
Keyless Entity Types
Configure Precision and Scale
Translation of Contains on byte arrays
Many-to-many Relationship
Table-per-type (TPT) mapping
Required one-to-one Dependents
Support for Fields using Lambda
Drop Column from SQLite Database
Index Attribute
Connection Strings: Entity Framework Core
Entity Framework Core Model
DbContext
DbSet
Relationship in EF-Core
Lazy Loading in EF Core
Migrations in EF-Core
Handling Concurrency in EF-Core
Raw SQL Queries in EF-Core
Database Providers
Project Types
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Simple Logging
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Simple Logging

Simple Logging is the equivalent of Database.Log in EF6. It provides a simple way to get logs from EF Core without the need to configure any kind of external logging framework.
EF Core replaces Database.Log with a LogTo method called on DbContextOptionsBuilder in either AddDbContext or OnConfiguring.
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
=> optionsBuilder.LogTo(Console.WriteLine);
There are multiple overloads available which can be used in different use cases.
  • Set the minimum log level
    • Example: .LogTo(Console.WriteLine, LogLevel.Information)
  • Filter for only specific events:
    • Example: .LogTo(Console.WriteLine, new[] {CoreEventId.ContextInitialized, RelationalEventId.CommandExecuted})
  • Filter for all events in specific categories:
    • Example: .LogTo(Console.WriteLine, new[] {DbLoggerCategory.Database.Name}, LogLevel.Information)
  • Use a custom filter over event and level:
    • Example: .LogTo(Console.WriteLine, (id, level) => id == RelationalEventId.CommandExecuting)
Output format can be minimally configured (API is in flux) but the default output looks something like:
warn: 12/5/2019 09:57:47.574 CoreEventId.SensitiveDataLoggingEnabledWarning[10400] (Microsoft.EntityFrameworkCore.Infrastructure)
Sensitive data logging is enabled. Log entries and exception messages may include sensitive application data, this mode should only be enabled during development.
dbug: 12/5/2019 09:57:47.581 CoreEventId.ShadowPropertyCreated[10600] (Microsoft.EntityFrameworkCore.Model.Validation)
The property 'BlogId' on entity type 'Post' was created in shadow state because there are no eligible CLR members with a matching name.
info: 12/5/2019 09:57:47.618 CoreEventId.ContextInitialized[10403] (Microsoft.EntityFrameworkCore.Infrastructure)
Entity Framework Core 5.0.0-dev initialized 'BloggingContext' using provider 'Microsoft.EntityFrameworkCore.SqlServer' with options: SensitiveDataLoggingEnabled
dbug: 12/5/2019 09:57:47.644 CoreEventId.ValueGenerated[10808] (Microsoft.EntityFrameworkCore.ChangeTracking)
'BloggingContext' generated temporary value '-2147482647' for the 'Id' property of new 'Blog' entity.
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