Saving Data on Android

Database Access Objects
.
Saving Data on Android
Chapter 7: Mastering Relations
raywenderlich.com
129

---

Key points
• An entity relation diagram, ER diagram or 
ERD
 is a kind of flowchart that 
illustrates the relation between the components of a system.
• Entities represent a component, object or a concept of a system. They are usually 
translated as tables in your database.
• Entities in Crow's Foot notation also include a list of attributes or properties that 
define them.
• An attribute that can uniquely identify a record of your entity is known as a key 
attribute and they usually become primary keys in your database.
• A relationship tells you how two entities interact with each other and it is usually 
represented as a verb.
• The cardinality of an ERD tells you the kind of relationship that two entities have.
•