4.14- Left Outer Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS скачать в хорошем качестве

4.14- Left Outer Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS

4.14- Left Outer Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS PLAYLIST: DBMS - Data Base Management System Tutorials In Hindi | GATE- NET- DBMS Lectures in Hindi    • DBMS Complete Syllabus- All University exa...   Relational Algebra In DBMS | relational algebra database examples | relational database operators    • Relational Algebra In DBMS | relational al...   dbms tutorials, database management system tutorial, database tutorials, theta and equi join, outer join in relational algebra, relational algebra database examples, relational algebra in dbms, relational database operators, gate dbms tutorials, ugc net dbms tutorials, #gatedbmslecturesinhindi, #ugcnetdbmslecturesinhindi, #gatedbmslectures, #ugcnetdbmslectures, #dbmslectures #dbms tutorials Natural-join operation : Natural join is used to join two relations having any number of attributes. It is denoted by symbol (). It also optimize the query as Cartesian product gives unnecessary results and set-union and set-intersection operations are applicable only on those relations that have equal number of attributes ral join operation. (e) Outer join : Outer Join is an extension of natural join operations. It deals with the missing information caused by natural join operation. Suppose you need all information of all employees and all students in a single relation. Natural join () : The natural join (Employee  Student) gives the result as shown In this result, information about Ramesh, Jack, Vijay, Gaurav are missing. So, outer join is used to avoid this loss of information. There are Three types of outer joins. (i) Left outer join : It is used to take all tuples of relation that are on the left side whether they are matching with tuples of right side relation or not. It is denoted by ( ––). (Employee – – Student) gives EID SID Name Salary Fees 1E 5S John 10,000 950 2E NULL Ramesh 5,000 NULL 3E 1S Smith 8,000 1,000 4E NULL Jack 6,000 NULL 5E 4S Nile 15,000 1,500 FIGURE 5.14. Result of left outer join. Employee relation is at left side so table in Figure 5.14 consists all information of Employee relation but still missing information about Vijay and Gaurav. (ii) Right outer join : It is used to take all tuples of relation that are on the right side whether they are matching with tuples of left side relation or not. It is EID SID Name Salary Fees 3E 1S Smith 8,000 1,000 NULL 2S Vijay NULL 950 NULL 3S Gaurav NULL 2,000 5E 4S Nile 15,000 1,500 1E 5S John 10,000 950 FIGURE 5.15. Result of right outer join. Student relation is at right side so table in Figure 5.15 consists all information of Student relation but still missing information about Ramesh and Jack. (iii) Full outer join : It is used to take all tuples from left and right relation whether they match with each other or did not match. It is denoted by Relational Algebra and Calculus 169 EID SID Name Salary Fees 1E 5S John 10,000 950 2E NULL Ramesh 5,000 NULL 3E 1S Smith 8,000 1,000 4E NULL Jack 6,000 NULL 5E 4S Nile 15,000 1,500 NULL 2S Vijay NULL 1,000 NULL 3S Gaurav NULL 2,000 4.1- What Is Relational Algebra | Relational Algebra In DBMS | Relational Operators In DBMS    • 4.1- What Is Relational Algebra In dbms in...   4.2- Relational Operations In Relational Algebra | Relational Algebra- relational database operators    • 4.2- Relational Operations In Relational A...   Notes Link: http://www.tutorialsspace.com/Downloa...