Open-Source Databases · linq2db

linq2db

LINQ to DB is a lightweight, type-safe C# ORM that sits between micro-ORMs like Dapper and full-featured frameworks like Entity Framework. It translates LINQ expressions directly to SQL, offering compile-time query safety without the overhead of change-tracking or heavy object mapping.

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Source: GitHub — github.com/linq2db/linq2db

3.3k

GitHub stars

478

Forks

Primary language

MIT

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	linq2db/linq2db
Owner	linq2db
Primary language	C#
License	MIT — OSI-approved
Stars	3.3k
Forks	478
Open issues	355
Latest release	v6.3.0 (2026-05-17)
Last updated	2026-07-08
Source	https://github.com/linq2db/linq2db

What linq2db is

LINQ to DB is a thin abstraction layer for .NET that compiles LINQ expressions to SQL and supports 15+ database backends (SQL Server, PostgreSQL, MySQL, Oracle, SQLite, etc.). It provides rich querying capabilities (CTEs, window functions, bulk operations, merge API) while maintaining performance through minimal runtime overhead and no automatic change-tracking.

Quickstart

Get the linq2db source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/linq2db/linq2db.git2cd linq2db3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

High-performance transactional systems requiring type-safe queries

Systems where compile-time query validation, explicit control over SQL, and minimal ORM overhead are critical—financial services, real-time dashboards, high-throughput APIs.

Multi-database applications with complex SQL requirements

Projects needing support for diverse backends (SQL Server, PostgreSQL, Oracle, etc.) with sophisticated queries (CTEs, window functions, bulk copy) that would be cumbersome in EF Core.

Incremental migration from legacy SQL or Dapper codebases

Teams moving from raw SQL or micro-ORMs to type-safe LINQ but unwilling to adopt the architectural constraints and performance trade-offs of Entity Framework.

Implementation considerations

Requires manual schema mapping via attributes or fluent configuration; use linq2db.cli tool to generate POCOs from existing databases to reduce boilerplate.
No automatic relationship loading; eager-load related data explicitly in queries, which improves performance predictability but demands intentional query design.
Supports F# via LinqToDB.FSharp; evaluate if your team has polyglot requirements.
ASP.NET Core integration via DataOptions DI; register configured options once in container rather than per-request to avoid connection overhead.
Bulk operations (copy, merge, CTE) are first-class features; leverage these for batch workloads to justify adoption over simpler micro-ORMs.

When to avoid it — and what to weigh

Your team prioritizes rapid prototyping and minimal database schema cognition — LINQ to DB requires explicit schema understanding and manual query composition; frameworks with auto-migrations and scaffolding (EF Core, Hibernate) are faster for exploratory projects.
You need built-in change-tracking or lazy-loading relationships — LINQ to DB deliberately omits change-tracking; if your domain model relies on automatic dirty-checking or implicit relationship loading, adopt EF Core or NHibernate instead.
Your organization has deep Entity Framework investments or patterns — Switching ORMs carries significant cognitive and integration costs; the project provides EF.Core bridge support but is not a drop-in replacement for established EF architectures.
You require out-of-the-box identity/security providers or scaffolding tooling — While LinqToDB.Identity exists, mainstream .NET tooling (CLI, Azure DevOps integrations) is optimized for EF Core; LINQ to DB's ecosystem is narrower.

License & commercial use

MIT License. Permissive; allows commercial use, modification, and redistribution with attribution. No copyleft obligations. Disclaimer of warranty applies.

MIT is a permissive OSI license explicitly compatible with commercial use. No license review is strictly required for deployment. However, verify compliance with any proprietary dependencies (database drivers, etc.) your deployment pulls in, and confirm your legal/procurement team accepts MIT's liability disclaimer.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Adequate
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Good
Assessment confidence	High

Security considerations

LINQ to DB compiles parameterized SQL, mitigating SQL injection at the expression level. No explicit security audit data provided. Standard .NET connection pooling and credential management practices apply (use secure connection string storage, rotate credentials, least-privilege database accounts). Dependency on database client libraries (SqlClient, Npgsql, etc.) inherits their security posture; keep drivers updated.

Alternatives to consider

Entity Framework Core

Full-featured ORM with change-tracking, auto-migrations, and LINQ support. Heavier, slower on complex queries, but better for rapid prototyping and domain-driven design. Preferred if team ownership and maintainability outweigh performance.

Dapper

Lightweight micro-ORM focused on raw SQL with parameter mapping. Faster than LINQ to DB for simple queries, no LINQ overhead. Choose if you want explicit SQL control and accept losing compile-time query validation.

NHibernate

Mature enterprise ORM with deep change-tracking, lazy-loading, and caching. Steeper learning curve and configuration overhead. Consider if migrating legacy .NET Framework systems or require advanced session management.

Software development agency

Build on linq2db with DEV.co software developers

If your team values compile-time query safety, explicit SQL control, and performance without change-tracking overhead, LINQ to DB is worth a technical spike. Start with the GitHub examples repo and benchmark against your existing ORM.

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linq2db FAQ

Does LINQ to DB support async queries?

Yes. The README and documentation reference async patterns; verify specific async method availability for your target database version in docs or source.

Can I use LINQ to DB alongside Entity Framework in the same application?

Yes. The project provides linq2db.EntityFrameworkCore to bridge both; however, manage separate DbContexts/DataConnections per ORM to avoid transaction conflicts.

What's the performance difference versus Entity Framework?

Not quantified in provided data. LINQ to DB claims to be 'fastest LINQ database access library' but no benchmarks are provided; conduct your own benchmarks with real workloads.

Does LINQ to DB support NoSQL databases?

No. The project is SQL-focused and supports 15+ relational databases. For NoSQL, use MongoDB drivers, CosmosDB SDKs, or Firebase libraries directly.

Software development & web development with DEV.co

Adopting linq2db is usually one piece of a larger software development effort. As a software development agency, DEV.co provides software development services and web development expertise — pairing senior software developers and web developers with your team to design, build, and operate open-source databases software in production.

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