1 votes 1 votes Joins and Cross products are associative or commutative? Databases databases + – rahul sharma 5 asked Jan 5, 2017 • retagged Aug 5, 2017 by Arjun rahul sharma 5 3.5k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Cross Product : is both associative and commutative Natural Inner Join : is also both associative and commutative. Note: 1) In a relation order of the tuples and columns is insignificant. Kaushik.P.E answered Jan 5, 2017 Kaushik.P.E comment Share Follow See all 2 Comments See all 2 2 Comments reply rahul sharma 5 commented Jan 5, 2017 reply Follow Share Natural inner join is same as natural join? 0 votes 0 votes Kaushik.P.E commented Jan 5, 2017 reply Follow Share Every join operator has two components namely 1) Join Condition , which dictates: i) how to handle attributes in the resultant relation ii) how to compare tuples. There are two join conditions a) Natural i) take union of attributes ii) match on common column b) On i) Duplicates of attributes are also allowed ii) Join condition is explicitly specified. eg(on a.salary> b.salary) 2) Join Type, which dictates i) how to handle unmatched tuples. eg; as you may know Full outer,left outer and right outer. So the term Natural join alone is incomplete, but is predominantly used to specify Natural Inner Join. And obviosuly Left and right outer join types are not commutative. 0 votes 0 votes Please log in or register to add a comment.