This is a simple and opinionated PostgreSQL migration tool.
This came about because I was duplicating migration functionality across multiple projects, and they all had the same behavior.
This tool uses github.com/jackc/pgx, so if you're using it, it won't pull in
unnecessary dependencies. On the flip side, if you're not, then it will (hence
the opinionated aspect).
The user passes in a directory that contains SQL migration files. These files are named in the following format:
$version_$name.up.sql
$version_$name.down.sql
The $version part defines the version number of the migration and $name
is used to define the name of the migration. This name is discarded, but should
be used to keep track of what the migrations are supposed to do.
If a migration ends in up.sql, it defines what should happen when you migrate
it up. If a migration ends in down.sql, it defines what should happen when you
migrate it down.
The tool will maintain a table called schema_migrations which has two columns:
| Column | Description |
|---|---|
version |
The version number, extracted from the filename |
migrated_at |
The timestamp of when the migration occurred. |
Only the most recent migration is shown in the table, in order to keep the table as small and fast as possible.
All pending migrations are performed in a transaction so that if any migration fails, they are rolled back without any changes.