One to One Relationships
- In a one-to-one relationship, a key will appear only once in a related table.
One to Many and Many to One Relationships
- In a one-to-many relationship, keys from one table will appear multiple times in a related table.
Many to Many Relationships
- In some cases, you may need multiple instances on both sides of the relationship.
Self Referencing Relationships
- Customers can refer other customers to your shopping website.
Foreign Keys
- we always had these "****_id" fields that referenced a column in another table.
- Defining the Foreign Key Explicitly
Without Explicit Declaration
- Visualizing the Relationships in MySQL Workbench
shortcuts
Non-identifying relationship
A non-identifying relationship means that a child is related to parent but it can be identified by its own.
Identifying relationship
An identifying relationship means that the parent is needed to give identity to child. The child solely exists because of parent.
