pg-migrations

Postgres Migrations

The purpose of this library is to provide liquibase like migration capabilities as a node module and command line interface.

Installation

npm install --global pg-migrations

Why?

liquibase provides many ways of managing migrations including xml, json, yaml, and sql formats for multiple database engines. However, these options can add to complexity, and unfortunately requires java to run.

The purpose of pg-migrations is to provide a simpler way (with fewer options) for managing postgresql database migrations without requiring java.

How it works

pg-migrations works with either a schema configuration file (either yaml, or json), or a directory.

Schema configuration file

The schema configuration file lists all the files to execute as part of the migration. Files can be defined as glob expressions and files matching the glob expression are executed in alpha numeric order (i.e. 1 < 2 < 10).

Example schema configuration file (example/database/schema.yml):

files:
  - '**/*.sql'

Directory

When a directory is used as an input to the migration, it effectively uses the same configuration as provided above (i.e. executes all sql files in the directory in alpha numeric order).

Migration file format

A migration file must start with --migration on the first line and contains one or many changesets (sql statements) preceded by a --changeset comment.

Changeset comment format

A changeset comment takes the following format:

--changeset [changeset name] [type:<once|always|change>] [context:<comma,separated,list>] 

Where:

• changeset name - (optional) name of the changeset, must be unique within the file
• type - (optional) execution type of the changeset, must be either execute once, always, or on change
  • defaults to once
  • note that a once migration script cannot be modified after it has already been executed (will result in an error on subsequent migrations)
• context - (optional) list of contexts that the changeset should be executed under
  • default behaviour is to execute under all contexts
  • context is specified using the --context command line argument, the omission of the --context argument implies all contexts will be executed

Example:

--migration 
--changeset create table 
create table my_table (
  val text
);
 
--changeset test data context:test 
insert into my_table (val)
values ('test data');

Usage

  Usage: pg-migration <schema file|directory> [options]

  Database migration tool for postgres databases

  Options:

    -h, --help                            output usage information
    -V, --version                         output the version number
    -c, --connection <connection string>  database connection string (required)
    -u, --user <user>                     database user name
    -p, --password <password>             database password
    -P, --prompt-password                 prompt for database password
    -s, --generate-script                 output sql script instead of executing the migration
    --context [contexts]                  changeset contexts to execute

Example

pg-migration database/schema.yml -c postgres://postgres@localhost/postgres -p password