What is PostgreSQL? Object-relational database management system (ORDBMS) Based on POSTGRES at Berkeley Computer Science Department. Sponsored by the Defense Advanced Research Projects Agency (DARPA), the Army Research Office (ARO), the National Science Foundation (NSF), and ESL, Inc. Implementation of POSTGRES began in It used a query language based on QUEL, called POST-QUEL

PostgreSQL MySQL Aimed to be a fully- featured database Understands a good subset of SQL92/99 dialects Rules, triggers, server-side functions can be written in C, PgSQL, Python, Perl and TCL Aimed first to be a fast database Uses SQL92 as its foundation Has simple mechanism for server-side libraries with C function and rudimentary support for triggers

PostgreSQL MySQL Supports subqueries, stored procedures, subqueries, cursors or views Supports referential integrity, has transactions and rollbacks, foreign keys ON DELETE CASCADE and ON UPDATE CASCADE Does not support subqueries, stored procedures, subqueries, cursors or views Has basic provisions for referential integrity and transactions/rollbacks

PostgreSQL MySQL Doesn't have binary distribution for all the support platforms Slower on low-end but has some options for improving Works better on Windows Fast on both simple and complex SELECTs

Roles and Databases

#!/bin/bash for student in do echo "CREATE ROLE $student WITH LOGIN;" | psql echo "CREATE DATABASE $student with OWNER $student;" | psql done

Creation Alternatives createdb psql --command //can't mix of psql and sql psql --file psql < filename

Other Command Line Options --hostname --username --password //force password prompt psql database username //default

Environment Variables PGDATABASE PGHOST PGPORT PGUSER

Useful Commands \connect \d [ pattern ] //list table, view, index, or sequence \dn [ pattern ] //list schemas \du [ pattern ] //list all roles \i filename //excute from file \l //list databases

Useful Commands \o [ {filename | |command} ] //Saves future query results to the file filename, standard output or pipes result to the Unix command \s [ filename ] //Saves the history to file or to standard output \set [ name [ value [... ] ] ] //Defines a variable \! [ command ] //Executes command on a Unix shell \? //Help the “+”

Sources psql man page Google "Postgres versus MySQL"