This is a measure of the number of unique values in a column compared to the total number of rows.
High Cardinality: Columns with many unique values, such as user IDs or email addresses. These columns are often good candidates for indexing.
Low Cardinality: Columns with few unique values relative to the number of rows, such as gender or status columns (like active/inactive). These may not benefit from indexing in the same way as high-cardinality columns.
. Importance of Cardinality in Database Design
Indexing: High cardinality columns are often good candidates for indexing to speed up query performance.
Query Optimization: Understanding cardinality helps optimize queries. For example, low-cardinality columns may not need indexing since it might not significantly improve query performance