A foreign key
A common attribute
The same number of attributes
Pupil_name has a functionality with Pupil_ID
Pupil_ID is functionally dependent on Pupil_name
Pupil_name is functionally dependent on Pupil_ID
These two attributes have a relationship
To speed up queries
To verify values
To create links between entities
To specify a lookup
Entity Integrity Rule
Referential Integrity Rule
Each primary key much be unique and not null
For each foreign key, there must be a corresponding primary key
Repeating groups are not permitted.
All attributes must have meaningful names.
The order of attributes is critical.
Each column must be unique.
No row should be duplicated.
All tables must contain a foreign key.