Define the five basic operators of relational algebra, Database Management System

Assignment Help:

Define the five basic operators of relational algebra?

Five 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 eliminated.
R = P ∪ Q
2. Minus (-) - Removes generally 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 belonging to the two relations and consisting of all probable combination of the tuples.
R = P × Q
4. Projection (ππππ) - The projection of a relation is described as a projection of all its tuples over a few set of attributes, i.e., it yields a vertical subset of the relation. It is used to either decrease the number of attributes (degree) in the resultant relation or to reorder attributes. The projection of a relation T on the attribute A is denoted through πA(T).
5. Selection (σσσσ) - Selects only some of the tuples, those satisfy given criteria, from the relation. It yields a horizontal subset of a given relation, i.e., the action is defined over a complete set of attribute names but just a subset of the tuples are involved in the result.
R = σB(P)

 


Related Discussions:- Define the five basic operators of relational algebra

Eliminate redundant data, Eliminate Redundant Data In the "Database Rel...

Eliminate Redundant Data In the "Database Relation" above, the primary key is made up of the D-ID and the Emp-ID. The database-name relies only on the D-ID. The similar databas

Built online transaction processing, Question: A DBMS built for Online ...

Question: A DBMS built for Online Transaction Processing (OLTP) is generally regarded as unsuitable for data warehousing. Each system is designed with a different set of requir

Sql iis setup and admin - maybe tfs, I want a good Microsoft Admin experien...

I want a good Microsoft Admin experienced in IIS and SQL Server. They require being able to set it up and administer from then onwards. Experience in Team Foundation Server a

What are called journaling file systems, What are called journaling file sy...

What are called journaling file systems? File systems that support log disks are known as journaling file systems.

Determine object representation, Determine object representation As a ...

Determine object representation As a designer, we must choose properly that when to use primitive types in representing objects and when to combine groups of related objects,

Database Management System, Assume that you are responsible for selecting a...

Assume that you are responsible for selecting a new DBMS product for Sohar Hospital

In the architecture of a database system which external leve, In the archit...

In the architecture of a database system which external level used? In the architecture of a database system view external level used.

Analyzing association traversal, Analyzing Association Traversal Assoc...

Analyzing Association Traversal Association Traversal shall be understood properly for the association design explanation.  Analyzing association traversal means analyzing tra

Give the reasons for allowing concurrency, Give the reasons for allowing co...

Give the reasons for allowing concurrency? The reasons for allowing concurrency is if the transactions run serially, a short transaction might have to wait for a preceding long

What is the archtetype pattern, What is the archtetype/instance pattern? ...

What is the archtetype/instance pattern? The archetype/instance pattern happens when one entity tracks occurrences of another entity. A common example is the relationship among

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