9.3.5 Documenting the sakila Database

This chapter demonstrates the capabilities of MySQL Workbench as a documentation tool by using the sakila database, which is a database sample provided by MySQL. You can find this database sample, and others, by visiting the https://dev.mysql.com/doc/index-other.html page.

An EER diagram provides a quick overview and understanding of a database. Rather than reading through table definition statements, a quick glance at an EER diagram indicates how tables are related.

You can also see how tables are related; what the foreign keys are and what the nature of the relationship is.

A PNG File of the sakila Database

Find following an EER diagram showing the tables in the sakila database. The following figure shows the output that was created using the File, Export, Export as PNG menu item.

Figure 9.35 The sakila Database EER Diagram

The object notation style used in Figure 9.35, “The sakila Database EER Diagram” is Workbench (PKs only). This notation shows only primary keys and no other columns, which is especially useful where space is at a premium. The relationship notation is the default, Crow's Foot.

As the connection lines show, each table is related to at least one other table in the database (with the exception of the film_text table). Some tables have two foreign keys that relate to the same table. For example the film table has two foreign keys that relate to the language table, namely fk_film_language_original and fk_film_language. Where more than one relationship exists between two tables, the connection lines run concurrently.

Identifying and non-identifying relationships are indicated by solid and broken lines respectively. For example, the foreign key category_id is part of the primary key in the film_category table so its relationship to the category table is drawn with a solid line. On the other hand, in the city table, the foreign key, country_id, is not part of the primary key so the connection uses a broken line.