Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Consider the subsequent relation schemes:
Project (Project#, Project_name, chief_architect)
Employee (Emp#, Empname)
Assigned_To (Project#, Emp#)
Give expression in Tuple calculus and Domain calculus for each of the queries below:
(i) Get the employee numbers of employees who work on all projects.
(ii) Get the employee numbers of employees who do not work on the COMP123 project.
Ans: (i) Tuple Calculus:
{t[Emp#] | t ∈ ASSIGNED_TO ∧ ∀p (p ∈ PROJECT ∃u (u ∈ ASSIGNED_TO ∧ p[Project#] = u[Project#] ∧ t[Emp#] = u[Emp#]))}
Domain Calculus:
{e | ∃p (
∈ ASSIGNED_TO ∧ ∀p1 ( ∈ PROJECT ∈ ASSIGNED_TO))}
(ii) Tuple Calculus:
{t[Emp#] | t ∈ ASSIGNED_TO ∧ ¬∃u (u ∈ ASSIGNED_TO ∧ u[Project#] = 'COMP123'∧ t[Emp#] = u[Emp#])}
∈ ASSIGNED_TO ∧ ∀p1, e1 ( ∉ ASSIGNED_TO ∨ p1 ≠ 'COMP123' ∨ e1 ≠ e))}
A relationship set is a set of relationships of the similar type. For example, let consider the relationship among two entities sets course and student. Collection of all the in
Support by Adding Indexes Multiple indexes can be used to access a data file by multiple access paths. In such a scheme only single copy of the data is consider, only the numbe
What is a records management consultation? Our organization is an authority for disseminating your specific requirements and giving you with a solution to effectively manage yo
what is difference between circular inked lust and grunded linked list
Index And Tree Structure Let us talk about the data structure that is used for creating indexes. Can we use Binary Search Tree (BST) as Indexes? Let us initial reconsider
A Structure of a dependency diagram
The indices are accumulated in the index files. The data is accumulated in the data files. Indices give fast access to data items. For example, a book database may be managed in th
Control as a State Machine Engine First let us define the state machine: "the state machine is a machine which is an object but not an application object. It is a part of lang
Question 1 Suppose the employee employee id, name, designation, salary, attendance and address of any employee has to be stored in a database. You can store these data in a sequen
Design a gennalization and specialization hierarchy for an automobile sales company
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd