Question

Discuss importance of bitmap index and join with suitable examples

Answer 1

Bitmap indexes are used on low cardinality columns that mean column has relatively few unique values.

Ex: A column called Marital status which has only Married and unmarried as the two possible values are considered low cardinality because there are only two unique values in the column.


Joins: They are used to retrieve data from multiple tables.

Ex : select columns from table1 inner join table2 on table1.column = table2.column;