# Databases

This chapter is all about SQL and using relational databases to
store and query data using Python. We will only look at the ‘bare
bones’ low level interfaces (things like SQL Alchemy and ORMs are
topics a little too big to tackle in this small course). We will be
using SQLite3 in place of a ‘real’ database, but replacing it with
PostgreSQL or MariaDB or some big commercial database is a question
of changing a few lines. And then learning a lot of SQL to make good
use of them.

Demonstrations:

 1. (to be done)

Prep exercises:

 1. ‹bimport› – import books into a database
 2. ‹bexport› – export books from a database
 3. ‹bquery›  – query the book database
 4. ‹lcreate› – shopping with Python and SQL
 5. ‹lsearch› – retrieve shopping lists from the database
 6. ‹lupdate› – update lists in the database

Regular exercises:

 1. ‹schema›  – create tables given as JSON
 2. ‹upgrade› – same, but with schema upgrade
 3. ‹pkgs›    – simple queries on a package database
 4. ‹depends› – fetching transitive dependencies

Voluntary exercises:

 1. (nothing here yet)