Discuss in detail about data modeling.

• Data modelling makes use of the ERD.
• Consists of three interconnected information.

The data object.

Attributes.

Relationships.

Cardinality and Modality

• Cardinality means the specification of the number of occurrences of one object that can be linked to the number of occurrences of another object.
• One-to-one cardinality.
• One-to-many cardinality.
• Many-to-Many cardinality.
• Modality of a relation is 0 when no explicit relationship or relation is optional.
• Modality is 1 when occurrence of relationship is mandatory.

Entity/Relationship Diagrams

• Elements are

Data Objects.

Attributes.

Relationships.

Various type indicators.