Install schema-evolution-manager with Homebrew

Project links

• Homepage
• Package manager page

Commands and aliases

• sem-add
• sem-apply
• sem-baseline
• sem-dist
• sem-info
• sem-init

Project history

Schema Evolution Manager was created at Gilt Groupe to standardize PostgreSQL schema changes as ordinary source code. It records applied scripts in its own PostgreSQL schema and packages migrations as reproducible tarballs named from Git tags.

Its design was shaped by production experience: small timestamped changes, independent schema deployments, reproducible artifacts, and no automatic rollback. The project was publicly presented at PGDay NYC in 2013.

Adoption history

Gilt Groupe began using SEM in early 2012. The official README reports that it improved the reliability of production schema deployments across dozens of independent PostgreSQL databases.

The project was subsequently made available through RubyGems, direct installation, and Homebrew. Its explicitly framework-independent design allowed database changes to be managed separately from any particular application stack.

How it is used

A typical workflow initializes a Git repository with sem-init, adds timestamped SQL with sem-add, commits the scripts, builds a tagged tarball with sem-dist, and applies pending scripts with sem-apply. sem-baseline can register pre-existing migrations without executing them.

Database connection parameters can be supplied as a PostgreSQL URL or separate host, port, database, and user options. The official guide recommends ~/.pgpass for persistent credentials or --password for a temporary prompt-managed credential file.

Why package nerds care

SEM is an opinionated example of Unix-style migration tooling: several narrow commands, minimal dependencies, Git-managed SQL, immutable release tarballs, and deliberately no rollback facility. It captures an operational school that favors forward-only, peer-reviewed, incremental database changes over framework-bound migration abstractions.

Timeline

• Early 2012: Gilt Groupe began using SEM internally.
• 2013: SEM was presented at PGDay NYC.
• 2013–2016: The official repository's copyright notice records Gilt Groupe stewardship during this period.

Related projects

• PostgreSQL and psql: SEM applies migration scripts through PostgreSQL tooling.
• Git: SEM uses repositories and tags as the history and release model for schema changes.
• RubyGems and Homebrew: Officially documented installation channels.

Sources

• https://github.com/mbryzek/schema-evolution-manager#readme
• source_facts.package-manager