Cardinality definition is wrong

Hi! If I’m not mistaken, cardinality isn’t number of tuples in the relation, like count(*) - its the definition of the duplicated values in the attribute - mysql - What is the definition of cardinality in SQL - Stack Overflow
High cardinality - everything is unique, low cardinality - a lot of repeating values.

Course: Deep Dive into the Internals of the Database - Learn Interactively
Lesson: Classification Based on Data Model

Hi @Dmitry_Polovinkin,

I appreciate your message and the opportunity to clarify any concerns. In the relational database model, specifically drawing from set theory, the term ‘cardinality’ accurately denotes the total number of tuples (rows) in a relation (table). It’s important to note that, in this context, cardinality pertains to the count of tuples in the entire table, not the uniqueness of data values within a column. Rest assured, there is no mistake in the course.

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