LINQ to DB

LINQ to DB is the fastest LINQ database access library offering a simple, light, fast, and type-safe layer between your POCOs and your database.

Architecturally it is one step above micro-ORMs like Dapper, Massive, or PetaPoco, in that you work with LINQ expressions, not with magic strings, while maintaining a thin abstraction layer between your code and the database. Your queries are checked by the C# compiler and allow for easy refactoring.

However, it's not as heavy as LINQ to SQL or Entity Framework. There is no change-tracking, so you have to manage that yourself, but on the positive side you get more control and faster access to your data.

In other words LINQ to DB is type-safe SQL.

LINQ to DB also very nice for F# developers (see Tests/FSharp and Source/LinqToDB.FSharp project for details).

Development version nugets feeds (how to use)

Standout Features

• Rich Querying API:
  • Explicit Join Syntax (In addition to standard LINQ join syntax)
  • CTE Support
  • Bulk Copy/Insert
  • Window/Analytic Functions
  • Merge API
• Extensibility:
  • Ability to Map Custom SQL to Static Functions

See Github.io documentation for more details.

Code examples and demos can be found here or in tests.

Release notes page.

Related Linq To DB and 3rd-party projects

• linq2db.EntityFrameworkCore (adds support for linq2db functionality in EF.Core projects)
• linq2db.Identity - ASP.NET Core Identity provider using Linq To DB
• LINQPad Driver
• DB2 iSeries Provider
• ASP.NET Core Template
• PostGIS extensions for linq2db

Notable open-source users:

• nopCommerce - popular open-source e-commerce solution
• OdataToEntity - library to create OData service from database context
• SunEngine - site, blog and forum engine

Unmantained projects:

• IdentityServer4.LinqToDB - IdentityServer4 persistence layer using Linq To DB

Configuring connection strings

Passing Into Constructor

You can simply pass connection string into DataConnection or DataContext constructor using DataOptions class.

Minimal configuration example:

var db = new DataConnection(
  new DataOptions()
    .UseSqlServer(@"Server=.\;Database=Northwind;Trusted_Connection=True;"));

Use connection configuration action to setup SqlClient-specific authentication token:

var options = new DataOptions()
  .UseSqlServer(connectionString, SqlServerVersion.v2017, SqlServerProvider.MicrosoftDataSqlClient)
  .UseBeforeConnectionOpened(cn =>
    {
        ((SqlConnection)cn).AccessToken = accessToken;
    });

// pass configured options to data context constructor
var dc = new DataContext(options);

[!TIP] There are a lot of configuration methods on DataOptions you can use.

[!TIP] It is recommended to create configured DataOptions instance once and use it everywhere. E.g. you can register it in your DI container.

Using Config File (.NET Framework)

In your web.config or app.config make sure you have a connection string (check this file for supported providers):

<connectionStrings>
  <add name="Northwind" 
    connectionString = "Server=.\;Database=Northwind;Trusted_Connection=True;" 
    providerName     = "SqlServer" />
</connectionStrings>

Using Connection String Settings Provider

Alternatively, you can implement custom settings provider with ILinqToDBSettings interface, for example:

This is the beginning of the README. Read the rest at the original. Read the full README ↗