Dbms navathe

Question

Consider the entity type DEPENDENT, related to EMPLOYEE, which is used to keep
track of the dependents of each employee via a 1:N relationship,(assume dependent is weak entity)
Please explain that how we are saying that it is 1:N relationship? if possible then explain it with table.

Comments

Are you saying, 1:N is from Employee to Dependent ? ---- it is OK

1:N is from Dependent to Employee ? ---- it is incorrect

 

1:N is from Employee to Dependent ===> it means, One Employee has Many Dependents.

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@shaikh sir as @sumeet has explained that why it is having 1:n relationship because the cardinality of dependent here is 1 and cardinality of employee is n (employee has two children) but  i asked this question because of that exception part that @sumeet has said in his explanation it can be many to many but  in this type of questions about strong entity to weak entity relationship  cardinality ratio is 1:n(given) in textbook  so actually what we have to do here in these question ?

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Employee is a different entity and Dependent is a different entity

a tuple of Employee can't be in the Dependent entity.

 

to more clearly understand, take the attributes of Employee and attributes of Dependent.

Answer 1

From what I understand dependents here mean son or daughter. Now an employee can have as many children(dependents) as possible (poor family planning ;) ). This means that from Employee to Dependents , the relationship is definitely 1:N.

Also there is no way an employee database will have key attributes for dependents entity, therefore the children will be identified by their parent. So dependents is definitely a weak entity with total participation.

$Exception$

If it turns out that both husband and wife are working in the same organization then its definitely N:N(many-to-many) relationship.