Ferrule

The collar that joins you to your data.

Ferrule is a Rust-native command-line tool for querying relational databases. One static binary speaks PostgreSQL, MySQL, MSSQL, and SQLite. Oracle is optional via feature flag.

Features

• Zero runtime dependencies for default backends (no libpq, libmysqlclient, or unixodbc required).
• Unified type system — every backend maps native types to a single Value enum.
• Multiple output formats — table, JSON, CSV, YAML, raw.
• Interactive REPL with history, bookmarks, query parameters, and watch mode.
• Schema introspection — tables and describe against any backend.
• Server-side paging with --limit and --offset.
• Connection registry — save named connections in ~/.config/ferrule/.
• EXPLAIN execution plans across all backends.
• Dump / Load data to/from CSV and JSON.
• Watch mode for monitoring queries in real time.

One-minute Demo

# SQLite works out of the box
ferrule query "sqlite::memory:" "SELECT 1 + 1 AS answer;"

# Postgres (requires running server)
ferrule query "postgres://user:pass@localhost/db" "SELECT * FROM users;" --format json

# Interactive REPL
ferrule repl "sqlite::memory:"
> SELECT random() % 100 AS lucky_number;
> \format json
> SELECT * FROM sqlite_master;
> \q