pg_delta

PgDelta

pg_delta provides an easy way to obtain information about a PostgreSQL query. Here's a motivating example.

Given a file /tmp/a.sql:

update users
  set name = 'Unknown'
  where name is null;

alter table users
  alter column name
  set not null;

truncate table passwords;

Running pg_delta will then yield the following JSON:

$ exe/pg_delta -f /tmp/a.sql
[
  {
    "mutation": "update_data",
    "type": "data",
    "details": {
      "table_name": "users",
      "column_names": [
        "name"
      ]
    }
  },
  {
    "mutation": "alter_table_set_not_null",
    "type": "column",
    "details": {
      "table_name": "users",
      "column_name": "name"
    }
  },
  {
    "mutation": "truncate_table",
    "type": "table",
    "details": {
      "table_names": [
        "passwords"
      ]
    }
  }
]

Installation

Install the gem and add to the application's Gemfile by executing:

$ bundle add pg_delta

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install pg_delta

Usage

Usage: pg_delta -f FILES

Example:
  $ pg_delta -f 1.sql 2.sql 3.sql

Options:
    -v, --version                    Print the version
    -f, --files FILES                The files to parse
    -h, --help                       Show this message

Types of Changes

The types of changes are as follows:

:column
:domain
:enum
:function
:table
:trigger
:data
:index
:type
:view
:constraint
:unknown

Mutations

The following mutations are identified:

# :column
:alter_table_add_column
:alter_table_set_column_default
:alter_table_drop_column_default
:alter_table_drop_column
:alter_table_drop_not_null
:alter_table_set_not_null
:alter_table_rename_column

# :domain
:alter_domain
:create_domain
:drop_domain

# :enum
:alter_enum
:create_enum

# :function
:create_function
:drop_function
:rename_function

# :table
:create_table
:create_table_as
:drop_table
:rename_table
:truncate_table

# :trigger
:create_trigger
:drop_trigger
:disable_trigger
:enable_trigger
:rename_trigger

# :data
:delete_data
:insert_data
:update_data

# :index
:create_index
:drop_index
:rename_index

# :type
:alter_table_alter_column_type
:drop_type
:rename_type

# :view
:create_view
:drop_materialized_view
:drop_view

# :constraint
:alter_table_add_constraint
:alter_table_drop_constraint
:alter_table_validate_constraint
:alter_table_rename_constraint

# :unknown
:unknown

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rhizomic/pg_delta. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.