Which type of JOIN returns all matching rows from both tables, plus all unmatched rows from the left table with NULL values filled in for the right table columns? MCQ with Answer and Explanation

Which type of JOIN returns all matching rows from both tables, plus all unmatched rows from the left table with NULL values filled in for the right table columns?
A. Full Outer Join
B. Inner Join
C. Right Outer Join
D. Left Outer Join
Answer: Option D
Solution (By JKSSB Mock Tests)
A Left Outer Join preserves all records from the left table, matching them with right table records when possible, or inserting NULL values if no match is found.

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Practice More Database Management System (DBMS) Questions

Question #1
Which of the following database models organizes data in a tree-like upside-down structure with parent-child relationships?
A. Network Model
B. Hierarchical Model
C. Relational Model
D. Object-Oriented Model

Correct Answer: Option B


Explanation:
The Hierarchical Model stores data in a tree-like configuration where each child node has exactly one parent node.

This question belongs to: Computer Database Management System (DBMS)
Question #2
An attribute that can be broken down into smaller, independent sub-parts with independent meanings (such as Name into First_Name and Last_Name) is called a what?
A. Simple Attribute
B. Composite Attribute
C. Multi-valued Attribute
D. Derived Attribute

Correct Answer: Option B


Explanation:
A Composite Attribute is one that can be divided into smaller sub-components or meaningful independent fields.

This question belongs to: Computer Database Management System (DBMS)
Question #3
What is the role of the 'WHERE' clause in an UPDATE statement?
A. To sort the results
B. To specify the new values
C. To join tables
D. To specify which rows to update

Correct Answer: Option D


Explanation:
The WHERE clause in UPDATE identifies the rows that will be updated. Without it, all rows would be updated.

This question belongs to: Computer Database Management System (DBMS)