postgreSQL intro

https://wiki.postgresql.org/wiki/Things_to_find_out_about_when_moving_from_MySQL_to_PostgreSQL

Things to find out about when moving from MySQL to PostgreSQL

1. create table

drop table if exists Ratings;
CREATE TABLE Ratings
(
  "UserID" text,
  "MovieID" text,
  "Rating" double precision,
  PRIMARY KEY("UserID", "MovieID")
);