Semi-Join with Examples in Relational Algebra (Database Systems)
Today, in this fresh and new article, we will cover the following topics;
- What is Semi Join?
- Examples of Semi Join
What is Semi Join?
Semi-Join matches the rows of two relations and then show the matching rows of the relation whose name is mentioned to the left side of ⋉ Semi Join operator. I am describing the more details in the below examples. Hopefully, it will help you to understand the semi-join.
Example 1 of Semi Join
| ID | Rank | Salary |
| 101 | Assistant Professor | 80,000 |
| 102 | Associate Professor | 90,000 |
| 103 | Lecturer | 70,000 |
Table 1: Teacher
| ID | RollNo | Marks |
| 103 | 2017 – 01 | 80 |
| 104 | 2017 – 02 | 90 |
| 105 | 2017 – 03 | 70 |
Table 2: Student
| ID | RollNo | Marks |
| 103 | 2017 – 01 | 80 |
Table 3: Student ⋉ Teacher OR Student Semi Join Teacher
| ID | Rank | Salary |
| 103 | Lecturer | 70,000 |
Table 4: Teacher ⋉ Student OR Teacher SEMI-JOIN Student
Example 2 of Semi Join
| ID | Rank | Salary |
| 101 | Assistant Professor | 80,000 |
| 102 | Associate Professor | 90,000 |
| 103 | Lecturer | 70,000 |
Table 5: Teacher
| ID | RollNo | Marks |
| 101 | 2017 – 01 | 80 |
| 103 | 2017 – 02 | 90 |
| 106 | 2017 – 03 | 70 |
Table 6: Student
| ID | RollNo | Marks |
| 101 | 2017 – 01 | 80 |
| 103 | 2017 – 02 | 90 |
Table 7: Student ⋉ Teacher OR Student SEMI-JOIN Teacher:
| ID | Rank | Salary |
| 101 | Assistant Professor | 80,000 |
| 103 | Lecturer | 70,000 |
Table 8: Teacher ⋉ Student OR Teacher SEMI-JOIN Student
Example 3 of Semi Join
|
|
| ||||||||||||||||||||||||||||||||||||||
Topic Covered
Semi-Join with Examples in Relational Algebra, Database Systems.
CEO @ T4Tutorials.com
I welcome to all of you if you want to discuss about any topic. Researchers, teachers and students are allowed to use the content for non commercial offline purpose. Further, You must use the reference of the website, if you want to use the partial content for research purpose.
I welcome to all of you if you want to discuss about any topic. Researchers, teachers and students are allowed to use the content for non commercial offline purpose. Further, You must use the reference of the website, if you want to use the partial content for research purpose.
Latest posts by Prof. Fazal Rehman Shamil (see all)
- List of Public service commissions - August 31, 2020
- Comparison of fee structure of Pakistani Universities - June 1, 2020
- Past Guess Paper of Auditing - May 12, 2020