12-06-2014, 03:48 PM
E-R Model
E-R Model.docx (Size: 111.59 KB / Downloads: 13)
Analyze the problem carefully and come up with the entities in it. Identify what data has to be persisted in the database. This contains the entities, attributes etc.Identify the primary keys for all the entities. Identify the other keys like candidate keys, partial keys if any.
BUS Entity:
The attributes are:
i. Bus_No
ii. Source
iii. Destination
iv. Dep_Time
TICKET Entity:
The attributes are:
i. Ticket_No
ii. Journey_Date
iii. Age
iv. Sex
v. Source
vi. Destination
vii. Dep_Time
RESERVATION Entity:
The attributes are:
i. PNR_NO
ii. Journey_Date
iii. No_Of_Seats
iv. Address
v. Contact_No
vi. Status
Concept Design with E-R Model
Relate the entities appropriately. Apply cardinalities for each relationship. Identify the strong entities and weak entities (if any). Indicate the type of relationships (total/partial). Try to incorporate generalization, aggregation, specialization etc wherever required.
Relational Model
Represent all the entities (Strong, Weak) in tabular fashion. Represent relationships in a tabular fashion. There are different ways of representing relationships as tables based on the cardinality. Represent attributes as columns in tables or as tables based on the requirement. Different types of attributes (Composite, Multivalued and Derived) have different way of representation.