What's new in EF Core 6.0 preview 1

samples/core/Miscellaneous/NewInEFCore6/EntityTypeConfigurationAttributeSample.cs

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+using System;
+using System.Linq;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+public static class EntityTypeConfigurationAttributeSample
+{
+    public static void Using_EntityTypeConfigurationAttribute()
+    {
+        Console.WriteLine($">>>> Sample: {nameof(Using_EntityTypeConfigurationAttribute)}");
+        Console.WriteLine();
+
+        Helpers.RecreateCleanDatabase();
+        Helpers.PopulateDatabase();
+
+        using var context = new BooksContext();
+
+        var book = context.Books.Single(e => e.Id == 1);
+
+        Console.WriteLine();
+    }
+
+    public static class Helpers
+    {
+        public static void RecreateCleanDatabase()
+        {
+            using var context = new BooksContext();
+
+            context.Database.EnsureDeleted();
+            context.Database.EnsureCreated();
+        }
+
+        public static void PopulateDatabase()
+        {
+            using var context = new BooksContext();
+
+            context.Add(
+                new Book() { Isbn = "978-0-39-481823-8", Title = "What Do People Do All Day?" });
+
+            context.SaveChanges();
+        }
+    }
+
+    #region BookEntityType
+    [EntityTypeConfiguration(typeof(BookConfiguration))]
+    public class Book
+    {
+        public int Id { get; set; }
+        public string Title { get; set; }
+        public string Isbn { get; set; }
+    }
+    #endregion
+
+    #region BookConfiguration
+    public class BookConfiguration : IEntityTypeConfiguration<Book>
+    {
+        public void Configure(EntityTypeBuilder<Book> builder)
+        {
+            builder
+                .Property(e => e.Isbn)
+                .IsUnicode(false)
+                .HasMaxLength(22);
+        }
+    }
+    #endregion
+
+    #region DbContext
+    public class BooksContext : DbContext
+    {
+        public DbSet<Book> Books { get; set; }
+
+        //...
+        #endregion
+
+        private readonly bool _quiet;
+
+        public BooksContext(bool quiet = false)
+        {
+            _quiet = quiet;
+        }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder
+                .EnableSensitiveDataLogging()
+                .UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreSample");
+
+            if (!_quiet)
+            {
+                optionsBuilder.LogTo(Console.WriteLine, new[] { RelationalEventId.CommandExecuted });
+            }
+        }
+    }
+}

samples/core/Miscellaneous/NewInEFCore6/InMemoryRequiredPropertiesSample.cs

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+
+using System;
+using System.ComponentModel.DataAnnotations;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+
+public static class InMemoryRequiredPropertiesSample
+{
+    public static void Required_properties_validated_with_in_memory_database()
+    {
+        Console.WriteLine($">>>> Sample: {nameof(Required_properties_validated_with_in_memory_database)}");
+        Console.WriteLine();
+
+        using var context = new UserContext();
+
+        context.Add(new User());
+
+        try
+        {
+            context.SaveChanges();
+        }
+        catch (Exception e)
+        {
+            Console.WriteLine($"{e.GetType().FullName}: {e.Message}");
+        }
+
+        Console.WriteLine();
+    }
+
+    public static void Required_property_validation_with_in_memory_database_can_be_disabled()
+    {
+        Console.WriteLine($">>>> Sample: {nameof(Required_property_validation_with_in_memory_database_can_be_disabled)}");
+        Console.WriteLine();
+
+        using var context = new UserContextWithNullCheckingDisabled();
+
+        context.Add(new User());
+
+        context.SaveChanges();
+
+        Console.WriteLine();
+    }
+
+    #region UserEntityType
+    public class User
+    {
+        public int Id { get; set; }
+
+        [Required]
+        public string Username { get; set; }
+    }
+    #endregion
+
+    public class UserContext : DbContext
+    {
+        public DbSet<User> Users { get; set; }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder
+                .LogTo(Console.WriteLine, new[] { InMemoryEventId.ChangesSaved })
+                .EnableSensitiveDataLogging()
+                .UseInMemoryDatabase("UserContext");
+        }
+    }
+
+    public class UserContextWithNullCheckingDisabled : DbContext
+    {
+        public DbSet<User> Users { get; set; }
+
+        #region OnConfiguring
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder
+                .LogTo(Console.WriteLine, new[] { InMemoryEventId.ChangesSaved })
+                .UseInMemoryDatabase("UserContextWithNullCheckingDisabled")
+                .EnableNullabilityCheck(false);
+        }
+        #endregion
+    }
+}

samples/core/Miscellaneous/NewInEFCore6/NewInEFCore6.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <RootNamespace />
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="6.0.0-preview.1.21109.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="6.0.0-preview.1.21109.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="6.0.0-preview.1.21109.4" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="6.0.0-preview.1.21109.4" />
+  </ItemGroup>
+
+</Project>

samples/core/Miscellaneous/NewInEFCore6/PrecisionAttributeSample.cs

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+using System;
+using System.Linq;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+
+public static class PrecisionAttributeSample
+{
+    public static void Using_PrecisionAttribute()
+    {
+        Console.WriteLine($">>>> Sample: {nameof(Using_PrecisionAttribute)}");
+        Console.WriteLine();
+
+        Helpers.RecreateCleanDatabase();
+        Helpers.PopulateDatabase();
+
+        using var context = new BooksContext();
+
+        _ = context.Products.Single(e => e.Id == 1);
+
+        Console.WriteLine();
+    }
+
+    public static class Helpers
+    {
+        public static void RecreateCleanDatabase()
+        {
+            using var context = new BooksContext();
+
+            context.Database.EnsureDeleted();
+            context.Database.EnsureCreated();
+        }
+
+        public static void PopulateDatabase()
+        {
+            using var context = new BooksContext();
+
+            context.Add(new Product { Price = 3.99m });
+
+            context.SaveChanges();
+        }
+    }
+
+    #region ProductEntityType
+    public class Product
+    {
+        public int Id { get; set; }
+
+        [Precision(precision: 10, scale: 2)]
+        public decimal Price { get; set; }
+    }
+    #endregion
+
+    public class BooksContext : DbContext
+    {
+        public DbSet<Product> Products { get; set; }
+
+        private readonly bool _quiet;
+
+        public BooksContext(bool quiet = false)
+        {
+            _quiet = quiet;
+        }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder
+                .EnableSensitiveDataLogging()
+                .UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreSample");
+
+            if (!_quiet)
+            {
+                optionsBuilder.LogTo(Console.WriteLine, new[] { RelationalEventId.CommandExecuted });
+            }
+        }
+    }
+}

samples/core/Miscellaneous/NewInEFCore6/Program.cs

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+using System;
+
+public class Program
+{
+    public static void Main()
+    {
+        Console.WriteLine("Samples for _Accessing Tracked Entities_");
+        Console.WriteLine();
+
+        EntityTypeConfigurationAttributeSample.Using_EntityTypeConfigurationAttribute();
+        UnicodeAttributeSample.Using_UnicodeAttribute();
+        PrecisionAttributeSample.Using_PrecisionAttribute();
+        ToStringTranslationSample.Using_ToString_in_queries();
+        RandomFunctionSample.Call_EF_Functions_Random();
+        SparseColumnsSample.Use_sparse_columns();
+        InMemoryRequiredPropertiesSample.Required_properties_validated_with_in_memory_database();
+        InMemoryRequiredPropertiesSample.Required_property_validation_with_in_memory_database_can_be_disabled();
+        SqliteSamples.SavepointsApi();
+    }
+}

samples/core/Miscellaneous/NewInEFCore6/RandomFunctionSample.cs

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+using System;
+using System.Linq;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+
+public static class RandomFunctionSample
+{
+    public static void Call_EF_Functions_Random()
+    {
+        Console.WriteLine($">>>> Sample: {nameof(Call_EF_Functions_Random)}");
+        Console.WriteLine();
+
+        Helpers.RecreateCleanDatabase();
+        Helpers.PopulateDatabase();
+
+        using var context = new BooksContext();
+
+        #region Query
+        var users = context.Users.Where(u => u.Popularity == (int)(EF.Functions.Random() * 5.0) + 1).ToList();
+        #endregion
+
+        foreach (var user in users)
+        {
+            Console.WriteLine($"  Found '{user.Username}' with popularity '{user.Popularity}'");
+        }
+
+        Console.WriteLine();
+    }
+
+    public static class Helpers
+    {
+        public static void RecreateCleanDatabase()
+        {
+            using var context = new BooksContext(quiet: true);
+
+            context.Database.EnsureDeleted();
+            context.Database.EnsureCreated();
+        }
+
+        public static void PopulateDatabase()
+        {
+            using var context = new BooksContext(quiet: true);
+
+            context.AddRange(
+                new User { Popularity = 1, Username = "arthur" },
+                new User { Popularity = 2, Username = "wendy" },
+                new User { Popularity = 3, Username = "smokey" },
+                new User { Popularity = 4, Username = "alice" },
+                new User { Popularity = 5, Username = "mac" },
+                new User { Popularity = 1, Username = "baxter" },
+                new User { Popularity = 2, Username = "olive" },
+                new User { Popularity = 3, Username = "toast" });
+
+            context.SaveChanges();
+        }
+    }
+
+    #region UserEntityType
+    public class User
+    {
+        public int Id { get; set; }
+        public string Username { get; set; }
+        public int Popularity { get; set; }
+    }
+    #endregion
+
+    public class BooksContext : DbContext
+    {
+        public DbSet<User> Users { get; set; }
+
+        private readonly bool _quiet;
+
+        public BooksContext(bool quiet = false)
+        {
+            _quiet = quiet;
+        }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            optionsBuilder
+                .EnableSensitiveDataLogging()
+                .UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=EFCoreSample");
+
+            if (!_quiet)
+            {
+                optionsBuilder.LogTo(Console.WriteLine, new[] { RelationalEventId.CommandExecuted });
+            }
+        }
+    }
+}