What type of key uniquely identifies each record in a table and cannot contain NULL values? MCQ with Answer and Explanation

Explanation:
A self join is a join where a table is joined with itself, often used to compare rows within the same table.

Explanation:
A Right Outer Join retains all rows from the right table, pairing them with matching left table entries or supplying NULL values if matches do not exist.

Explanation:
The DEFAULT constraint assigns a predefined default value to a column when an INSERT statement does not explicitly provide a value for that column.