Question

In crow's foot E-R notation, what does a circle indicate?

1) A minimum cardinality of zero
2) A maximum cardinality of zero
3) A minimum cardinality of one
4) A maximum cardinality of one

Answer 1

In crow's foot E-R notation, a circle indicates a minimum cardinality of zero, meaning it represents an optional relationship where the presence of the related entity is not mandatory.

Step-by-step explanation:

In crow's foot E-R notation, a circle indicates a minimum cardinality of zero. This means that the entity represented by the circle may or may not have a relationship with another entity. It indicates an optional relationship where the presence of the related entity is not mandatory.

For example, if we have an entity called 'Customer' and another entity called 'Order', a circle on the 'Order' side of the relationship indicates that a 'Customer' entity may or may not have an associated 'Order', but it can have zero or more 'Orders'.

So, the correct answer is A minimum cardinality of zero (1).