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

What are the requirements of algorithm designer, What are the Requirements ...

What are the Requirements of algorithm designer Algorithm designer should: i) Select proper algorithm so as to minimize implementation cost ii) Find most appropriate d

Difference among a primary index and a secondary index, What is the differe...

What is the difference among a primary index and a secondary index? Primary Index: A primary index is an ordered file whose records are of fixed length along with two fields.

State the object design for processing, State the Object Design for Process...

State the Object Design for Processing  The object design phase comes after analysis and system design phase. The object design phase includes implementation details like as i

gaps in sequence values can happen when-sequences, Gaps in sequence values...

Gaps in sequence values can happen when: -     A rollback happens that is when a statement changes are not accepted. -     When the system crashes -     When a sequence i

Normalization, Normalize the given relation to 3NF, justifying each step

Normalize the given relation to 3NF, justifying each step

Data dictionary, The database is to record information about artists for a ...

The database is to record information about artists for a (music) production company. An artist is the name of a singer or band; the name of the artist, the year the artist started

Sub query in the update command, Sub query in the UPDATE command : Exam...

Sub query in the UPDATE command : Example :  //Double  the  commission  for  employees,  who  have  got  at  least  2 increments. UPDATE EMP SET COMM = COMM * 2 WHERE

Backward recovery (undo), Backward Recovery (UNDO): In this system the unco...

Backward Recovery (UNDO): In this system the uncommitted changes made by a transaction to a database are undone.  Instead the system is reset to the last consistent state of databa

What are the three types of data sources, What are the three types of data ...

What are the three types of data sources used with ODBC? An ODBC file data source is a file that can be shared between database users. An ODBC system data source is one that is

What are the advantages of relational data model, What are the advantages o...

What are the advantages of relational data model? Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer

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