Introduction
Weasel is a set of .NET libraries for database schema management and ADO.NET helpers. It gives you a programmatic API for defining database objects like tables, indexes, foreign keys, sequences, and functions, then handles the heavy lifting of detecting differences between your code-defined schema and the actual database, generating DDL, and applying migrations.
Origin and the Critter Stack
Weasel was extracted from the Marten project during its V4 development cycle. What started as Marten's internal schema management layer is now a standalone, general-purpose library and a foundational part of the Critter Stack -- the family of .NET libraries that includes Marten, Wolverine, and Polecat.
Weasel is developed and maintained by JasperFx Software.
Key Capabilities
- Programmatic schema definitions -- Define tables, columns, indexes, foreign keys, sequences, functions, and views in C# code
- Automatic delta detection -- Compare your expected schema against the actual database state and compute the minimal set of changes needed
- DDL generation -- Generate CREATE, ALTER, and DROP statements for any supported database engine
- Schema migration -- Apply detected changes automatically or review them before execution
- CLI migration tools -- Command-line interface for asserting schema validity, applying patches, and dumping DDL
- EF Core integration -- Use Weasel's migration infrastructure alongside Entity Framework Core
Supported Databases
| Database | Package |
|---|---|
| PostgreSQL | Weasel.Postgresql |
| SQL Server | Weasel.SqlServer |
| Oracle | Weasel.Oracle |
| MySQL | Weasel.MySql |
| SQLite | Weasel.Sqlite |
NuGet Packages
| Package | Description |
|---|---|
Weasel.Core | Core abstractions and migration infrastructure |
Weasel.Postgresql | PostgreSQL provider (Npgsql) |
Weasel.SqlServer | SQL Server provider (Microsoft.Data.SqlClient) |
Weasel.Oracle | Oracle provider (Oracle.ManagedDataAccess.Core) |
Weasel.MySql | MySQL provider |
Weasel.Sqlite | SQLite provider (Microsoft.Data.Sqlite) |
Weasel.EntityFrameworkCore | EF Core integration for Weasel migrations |
All provider packages automatically reference Weasel.Core, so you only need to install the provider for your database.
Next Steps
- Installation -- Add Weasel to your project
- Quick Start -- Define and migrate your first table in minutes