Fan Trap. It is presentation of a relation between enti

Fan Trap.
It is presentation of a relation between entity types of a model and existence of entity
occurrence between pathways ambiguous.
Chasm Trap
It is the model that a relationship exist between entity type, however there no existence of
pathway between entity occurrence.
'Redundant relationships
Major aim of relational database design is to group attributes into relations to minimize data
redundancy and reduce file storage space required by base relations.
Problems associated with data redundancy are illustrated by comparing different table
relations.
Normal Form
A relation / table is in the 1NF;
If there are no attributes (fields) that can have more than one value for a single instance (record).
If the intersection of each row and a column contains one and only one value. (Atomic value)
Second Normal Form.
A relation is in the 2NF,if it is already in the 1NF and if the values of all non primary key attributes are
dependent on the full primary key NOT part
Third Normal Form
A relation is in the 3NF if it is already in the 2NF and if the values of all non primary key attributes are
not dependant on non primary key attributes