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!
Define the basic operations of the relational algebra?
Ans: Basic operators of relational algebra are:
1. Union (∪) - Selects tuples which are in either P or Q or in both of them. The duplicate tuples are removed.
R = P ∪ Q
2. Difference or Minus (-) - eliminates common tuples from the first relation.
R = P - Q
3. Cartesian Product or Cross Product (×) - The cartesian product of two relations is the concatenation of tuples that are belonging to the two relations and containing all possible combination of the tuples.
R = P× Q
4. Projection (π) - The projection of a relation is illustrated as a projection of all its tuples over some set of attributes that is it yields a vertical subset of the relation. The relation's projection T on the attribute A is presented by T [A] or πA(T),.
5. Selection (σ) - Selects just some of the tuples, those satisfy specified criteria, from the relation. It yields a horizontal subset of a following relation.
R = σB(P)
For the relations R and S given below: R S A B C 1 4 7 2 5 8 3 6 9
Consider the table student and list names of students in the departments other than maths and computer. SELECT std_name FRM student WHERE dept_name NOT IN (‘Maths','Computer);
Define a table in SQL known as Client that is used to store information about the clients. Define CLIENT_NO as the primary key whose first letter must begin with ‘C'. Also ensure t
What is multiple relationship ?
Explain the Deferred Update The deferred update methods do not physically update the database on disk till after a transaction reaches its commit point; after that the updates
Question: a) What is Client/Server and what benefits can be expected from Client/Server systems? b) Explain what middleware is and what it does. Why would MIS managers be p
The Locking Protocol: To manage concurrency related problems we use locking. A lock is mainly a variable that is associated with a data item in the database. A lock can be located
Write short notes on Schema diagram. A database schema along with primary key and foreign key dependencies can be depicted pictorially by schema diagram. Every relation appears
You must implement the entity relationship model provided in the model solution to Assignment 1. The model solution will be released on the course website approximately TWO (2) we
Whst is logical schema ? Logical schema is the entire database.
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