We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
Relational Algebra - 4
Relational Algebra - 4
Sort by
recency
|
36 Discussions
|
Please Login in order to post a comment
Is this good idea to use it for my content based blog? Actually, i'm running a content based blog of soundbars.
navodayaresult is an initiative of experienced journalists who have got together to provide devoted news coverage of current events in India. Our team is made up of professional writers and citizen journalists with a wide range of journalism interests who are passionate about reporting Education Updates with transparency in the general public interest. https://navodayaresult2020-5th.in/ navodayaresult2020-5th.in Our reporting team plans to provide the Education & Recruitment Update for all age groups and to present the actual picture of recent events through inside coverage. Our goal is to meet the needs of people of all ages by publishing news categorised as General, Political, Crime, Sports, Entertainment, Education, and World News.
Selection: The selection operator is denoted by the sigma (σ) symbol. It is used to retrieve tuples from a relation that satisfy specific conditions or predicates. For example, σ(age > 30)(Employees) selects all employees from the "Employees" relation whose age is greater than 30.
Projection: The projection operator is denoted by the pi (π) symbol. It is used to extract specific attributes or columns from a relation while discarding the rest. For example, π(name, age)(Employees) retrieves only the "name" and "age" attributes from the "Employees" relation.
Union: The union operator (∪) combines tuples from two relations, eliminating duplicates, to create a new relation. It requires both relations to have the same attributes. For example, R ∪ S combines the tuples from relations R and S to create a new relation.
Intersection: The intersection operator (∩) returns the common tuples between two relations, creating a new relation. Like the union operator, it requires both relations to have the same attributes. For example, R ∩ S retrieves the tuples that are common to both relations R and S.
Difference: The difference operator (-) returns the tuples from one relation that are not present in another relation, creating a new relation. It requires both relations to have the same attributes. For example, R - S retrieves the tuples from relation R that are not found in relation S.
Join: The join operator (⨝) combines tuples from two relations based on a common attribute, creating a new relation. There are different types of joins, including inner join, left join, right join, and full outer join, depending on how the tuples are matched. For example, R ⨝ S combines tuples from relations R and S based on a common attribute.
Is relational algebra difficult ? free spell caster online