DynamicContext

Provides support for executing raw SQL queries against a Entity Framework Core DbContext without a DbSet for the entity. Itt also provides support to return a result set of single types (int, bool, Guid, string etc).

Installing AlwaysDeveloping.EntityFrameworkCore.DynamicContext

AlwaysDeveloping.EntityFrameworkCore.DynamicContext is available on NuGet via:

Install-Package AlwaysDeveloping.EntityFrameworkCore.DynamicContext

Or via the .NET CLI:

dotnet add package AlwaysDeveloping.EntityFrameworkCore.DynamicContext

Or via NuGet Packager Manager in Visual Studio

Direct link to AlwaysDeveloping.EntityFrameworkCore.DynamicContext on NuGet: https://www.nuget.org/packages/AlwaysDeveloping.EntityFrameworkCore.DynamicContext/

How to use AlwaysDeveloping.EntityFrameworkCore.DynamicContext

Configuring the dependency injection container

When using Entity Framework Core, when adding the DbContext to the DI container, use AddDynamicContext instead of AddContext

 host = Host.CreateDefaultBuilder()
    .ConfigureServices((context, services) => services
        .AddDynamicContext<BlogContext>(x => x.UseSqlite($"Data Source={Environment
            .GetFolderPath(Environment.SpecialFolder.MyDocuments)}\\BlogDatabase.db"))
    ).Build();

Using DynamicContext<T>

Inject DynamicContext<T> (where T is the underlying DbContext) into the relevant class.

Using the DynamicContext to retrieve data into an entity (or list of entities), without having a DbSet<>:

// Using the original underlying dbContext
// DbSet<Blog> must exists on the context
var blogs = dynContext.Context.Set<Blog>().AsNoTracking().ToList();

// Retrieving data dynamically
// DbSet<BlogUrl> does NOT need to exist on the context
var blogs = dynContext.Set<BlogUrl>()
    .FromSqlRaw("SELECT Id as BlogId, Url FROM Blog")
    .AsNoTracking().ToList();

// Retrieving data using anonymous object as a 'template' for the result
var anonBlogUrl = new { BlogId = 0, Url = "" };
var blogs = dynContext.Set(anonBlogUrl)
    .FromSqlRaw("SELECT Id as BlogId, Url FROM Blog")
    .AsNoTracking().ToList();

Using the DynamicContext to retrieve data into a simple type (or list of simple types) - simple types being value types (int, bool etc), Guid and strings:

// Retrieving Guid dynamically
// DbSet<Guid> does NOT exist on the context
var blogIds = dynContext.ValueSet<Guid>()
    .FromSqlRaw("SELECT Id as Value FROM Blog")
    .AsNoTracking().ToSimple().ToList();

// Retrieving string dynamically
// DbSet<string> does NOT exist on the context
var urls = context.StringSet<string>()
    .FromSqlRaw("SELECT Url as Value FROM Blog")
    .AsNoTracking().ToSimple().ToList();

Benchmarks

See this blog post for some simple benchmarks on comparing DbContext to DynamicContext (TLDR: DynamicContext is faster for the use cases tested)

Use cases

There are a variety of ways to retrieve the data using a DbContext - some more dynamic than others. This library address certain use cases not catered for by EF Core out the box.

The library is intended to be used in conjunction with, and complementing the EF Core DBContext functionality. If The EF Core DbContext be only being used to leverage the functionality of this library, it might make more sense to use a completely different ORM to handle the data access.