ERD DBMS

What is ERD used for?

• To show flow of data

• To show relationships between different data

• To explain details of data

• All of these

Which is not a type of attribute

• Derived

• Multivalued

• Composite

• Inherited

Relationship is shown by which symbol

• Dimond

• Rectangle

• Circle

• Eclips

If a student can have only one teacher and one teacher can teach many students what type of relationship is it?

• 1:1

• 1:M

• M:1

• M:N

If a relationship is multiple and optional the cardinality used will be

• 0 |

• | |

• 0 <—

• |<—

Bottom up division of entities is called

• Generalisation

• Speciallization

• Partilization

• None of the above

In disjoint constraint supper entitycan act as

• All sub entities

• Some sub entities

• 1 sub entity

• None

Total specialisation means supper class can only have

• All sub classes

• Some sub classes

• Only 1 sub class

• Multiple but not all

Aggregation is a ______ relationship

• HAS A

• IS A

• Both

• None

A person can be a student employee boy father son and husband this is an example of ____ constraint.

• Disjoint

• Overlapping

• Total specialisation

• Partial specialization