Demo of PostgreSQL FDW wrapping a CSV file + ActiveRecord

postgres_fdw_with_active_record.rb

# This is a demo of creating a Postgres FDW (foreign database wrapper)
# that encapsulates a CSV file.
# A CSV file can be manually updated and the PG table data will update too.


# Required steps in PostgreSQL
#
# 1. create a new database
# CREATE DATABASE foobar;
#
# 2. add required extension
# CREATE EXTENSION file_fdw;
#
# 3. create server
# CREATE SERVER my_server FOREIGN DATA WRAPPER file_fdw;
#
# 4. creating table that wraps a CSV file
# CREATE FOREIGN TABLE books (
#   id VARCHAR(255),
#   cat VARCHAR(255),
#   name VARCHAR(255),
#   price DECIMAL(5, 2),
#   inStock BOOLEAN,
#   author VARCHAR(255),
#   series VARCHAR(255),
#   sequence INTEGER,
#   genre VARCHAR(255)
# )
# SERVER my_server
# OPTIONS (
#   format 'csv', header 'true', filename 'path_to_file.csv', delimiter ',', null ''
# );

require "active_record"
require "pg"

ActiveRecord::Base.establish_connection(
  adapter:  "postgresql",
  database: "csv_file_fdw",
  username: "<username>",
  password: "<pass>",
  host:     "localhost",
  port:     "5432",
)

# this model "consumes" the above defined wrapper table
class Book < ActiveRecord::Base
end

this postgres feature is amazing ! Thanx for sharing