May 2018
Beginner to intermediate
452 pages
11h 26m
English
One effective way to help normalize our data and prepare it for a relational database is to analyze it and create an entity-relationship diagram, or ERD. An ERD is a way of diagramming the things which our database is storing information about and the relationships between those things.
Those things are called entities. An entity is a uniquely identifiable object; it corresponds to a single row of a single table. Entities have attributes, which correspond to the columns of its table. Entities have relationships with other entities, which correspond to the foreign key relationships we define in SQL.
Let's consider the entities in our lab scenario with their attributes and relationships: