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The Sakila example database

The Sakila database is a nicely normalised database modelling a DVD rental store (for those of you old enough to remember what that is). Its design includes a few nice features:

  • Many to many relationships
  • Multiple paths between entities (e.g. film-inventory-rental-payment vs film-inventory-store-customer-payment) to practice joins
  • Consistent naming of columns
    • Primary keys are called [tablename]_[id]
    • Foreign keys are called like their referenced primary key, if possible. This allows for using JOIN .. USING syntax where supported
    • Relationship tables do not have any surrogate keys but use composite primary keys
    • Every table has a last_update audit column
    • A generated data set of a reasonable size is available

ERD

ERD

With this database, we can try out some nice SQL queries, e.g. by using PostgreSQL syntax:

Actor with most films (ignoring ties)

SELECT first_name, last_name, count(*) films
FROM actor AS a
JOIN film_actor AS fa USING (actor_id)
GROUP BY actor_id, first_name, last_name
ORDER BY films DESC
LIMIT 1;

Yields:

first_name    last_name    films
--------------------------------
GINA          DEGENERES       42

Cumulative revenue of all stores

SELECT payment_date, amount, sum(amount) OVER (ORDER BY payment_date)
FROM (
  SELECT CAST(payment_date AS DATE) AS payment_date, SUM(amount) AS amount
  FROM payment
  GROUP BY CAST(payment_date AS DATE)
) p
ORDER BY payment_date;

Yields:

payment_date       amount         sum
-------------------------------------
2005-05-24          29.92       29.92
2005-05-25         573.63      603.55
2005-05-26         754.26     1357.81
2005-05-27         685.33     2043.14
2005-05-28         804.04     2847.18
2005-05-29         648.46     3495.64
2005-05-30         628.42     4124.06
2005-05-31         700.37     4824.43
2005-06-14          57.84     4882.27
2005-06-15        1376.52     6258.79
2005-06-16        1349.76     7608.55
2005-06-17        1332.75     8941.30
...

History

The Sakila example database was originally developed by Mike Hillyer of the MySQL AB documentation team. it was ported to other databases by DB Software Laboratory

License: BSD Copyright DB Software Laboratory http://www.etl-tools.com