Database-Management-System
August 29, 2024Transactions
August 29, 2024Database-Management-System
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Question 636
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For a weak entity set to be meaningful, it must be associated with another entity set in combination with some of their attribute values, is called as:
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Neighbour Set
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Strong Entity Set
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Owner Entity Set
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Weak Set
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Question 636 Explanation:
A weak entity set do not have any primary key using which we can identify it uniquely. So to uniquely identify a weak entity set it must be associated with its owner entity set and must have total participation in relationship with its owner entity set.
In above figure “Employee” can have many dependents and a dependent can belongs to only one employee. Now two dependents can have same names. So “Dependent” table don’t have any primary key to uniquely identify each dependent uniquely. So, it is a weak entity set and “Employee” entity is having “Emp No” as its primary key. Now using “Emp No. along with Name” in “dependent” relation each dependent can be uniquely identify. So we associated “Dependent” set with “Employee” set.
In above figure “Employee” can have many dependents and a dependent can belongs to only one employee. Now two dependents can have same names. So “Dependent” table don’t have any primary key to uniquely identify each dependent uniquely. So, it is a weak entity set and “Employee” entity is having “Emp No” as its primary key. Now using “Emp No. along with Name” in “dependent” relation each dependent can be uniquely identify. So we associated “Dependent” set with “Employee” set.
Correct Answer: C
Question 636 Explanation:
A weak entity set do not have any primary key using which we can identify it uniquely. So to uniquely identify a weak entity set it must be associated with its owner entity set and must have total participation in relationship with its owner entity set.
In above figure “Employee” can have many dependents and a dependent can belongs to only one employee. Now two dependents can have same names. So “Dependent” table don’t have any primary key to uniquely identify each dependent uniquely. So, it is a weak entity set and “Employee” entity is having “Emp No” as its primary key. Now using “Emp No. along with Name” in “dependent” relation each dependent can be uniquely identify. So we associated “Dependent” set with “Employee” set.
In above figure “Employee” can have many dependents and a dependent can belongs to only one employee. Now two dependents can have same names. So “Dependent” table don’t have any primary key to uniquely identify each dependent uniquely. So, it is a weak entity set and “Employee” entity is having “Emp No” as its primary key. Now using “Emp No. along with Name” in “dependent” relation each dependent can be uniquely identify. So we associated “Dependent” set with “Employee” set.