Installation

PolySchema is written in Go. You can install the polyschema command, use the Go library from your own module, or both. They read the same migration files.

Requirements

• Go 1.27.1 or later, to install the CLI with go install or to build against the library
• One of the supported databases:
  • PostgreSQL
  • MySQL
  • MariaDB
  • SQLite (no server needed)

Command-line tool

go install github.com/jc21/polyschema/cmd/polyschema@latest

This builds polyschema into $(go env GOPATH)/bin (usually ~/go/bin). Make sure that folder is on your PATH, then check the install:

polyschema -h

The CLI includes drivers for every supported engine, so you don't need to install anything else:

Engine	Driver
PostgreSQL	pgx
MySQL, MariaDB	go-sql-driver/mysql
SQLite	glebarez/go-sqlite (pure Go, no cgo)

To pin a version, replace @latest with a release tag, for example @v1.0.0.

Next: using the command line.

Go library

Add the module to your project:

go get github.com/jc21/polyschema

Then import the v1 package. It's named polyschema, but an explicit alias makes that clear to readers:

import polyschema "github.com/jc21/polyschema/v1"

The library doesn't import any database drivers. You open the *sql.DB yourself, so add the driver for your engine as well. Any database/sql driver works; these are the ones PolySchema is tested with:

PostgreSQL

go get github.com/jackc/pgx/v5
# import _ "github.com/jackc/pgx/v5/stdlib"   → sql.Open("pgx", dsn)

MySQL / MariaDB

go get github.com/go-sql-driver/mysql
# import _ "github.com/go-sql-driver/mysql"   → sql.Open("mysql", dsn)

SQLite

go get github.com/glebarez/go-sqlite
# import _ "github.com/glebarez/go-sqlite"    → sql.Open("sqlite", path)

Next: using the Go library.

Why /v1?

The Go module is github.com/jc21/polyschema, and v1/ is a package directory inside it. If the API ever needs a breaking change, it will go in a new v2/ package next to it, so code that imports /v1 keeps working. Go doesn't allow /v1 as a module suffix, which is why it's a package directory instead.

Trying it out locally

To try PolySchema without a database server, use SQLite. The DSN is just a file path:

polyschema -engine sqlite -dsn ./app.db -dir ./migrations

To try the other engines, the repository's docker-compose.yml starts throwaway PostgreSQL, MySQL and MariaDB servers:

git clone https://github.com/jc21/polyschema.git
cd polyschema
docker compose up -d

Engine	DSN
PostgreSQL	postgres://postgres:test@localhost:5432/postgres?sslmode=disable
MySQL	root:test@tcp(localhost:3306)/test
MariaDB	root:test@tcp(localhost:3307)/test

These use weak passwords and are meant for local testing only.