Red Flags of High Cardinality in Databases

The concept of high and low cardinality in databases refers to the number of unique values present in a column or set, with high cardinality indicating a large number of distinct values such as ID numbers, user names, or email addresses. Low cardinality, on the other hand, is characterized by repeated values like status flags, Boolean values, or gender. Understanding cardinality is essential for query performance and stability, particularly in databases that deal with complex data relationships. While calculating cardinality can be challenging, it's a crucial step in designing more efficient database systems and understanding how to optimize their performance.