Define the basic operations of the relational algebra, Database Management System

Assignment Help:

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)


Related Discussions:- Define the basic operations of the relational algebra

Candidate keys, Super keys of a relation can have extra attributes. Candida...

Super keys of a relation can have extra attributes. Candidate keys are minimal super key, i.e. such a key have no extraneous attribute. An attribute is known as extraneous if even

Identify the candidate keys, Consider the following six relation schemes an...

Consider the following six relation schemes and their corresponding sets of functional dependencies. In each case identify a. All the candidate keys b. The highest normal for

Customer service, as a customer service employee, explain five measures you...

as a customer service employee, explain five measures you would recommend a displeased student to patronise a school canteen

Load - unload utilities, These permit the user to unload a database or part...

These permit the user to unload a database or parts of a database and reload the data on the similar machine, or on another machine in a dissimilar location. This can be useful in

Designing the database schema , The domain that you will model in this assi...

The domain that you will model in this assignment is that of courses and students at a university. So as not to make the task too large and unspecified, you will here get a descrip

Large Project, Can you help me with the following: Drop statements for all...

Can you help me with the following: Drop statements for all objects in the lab project. Create statements for all objects of the lab project Create indexes for foreign keys Cre

Adjustments are required to increase chances of inheritance, What types of ...

What types of adjustments are required to increase chances of inheritance. a)   Some attributes can be added or ignored in  the base class operation  b) Some changes can be

Explain data sublangauges, Explain Data Sublangauges ? Data sublanguage...

Explain Data Sublangauges ? Data sublanguage: In relational database theory, the term sublanguage, first used for this purpose through E. F. Codd in the year of 1970, refers t

Hass, waht is a repeating group?

waht is a repeating group?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

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!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd