Table of Contents
Oracle Database - Rows (of Card as Cardinality for 9i)
About
Cardinality is the second measure that Query Plan Estimator use to estimate a execution plan.
It represents the number of rows in a row set that the Optimizer expects to come back.
Here, the row set can be :
- a base table,
- a view,
- or the result of a join or GROUP BY operator.
We can find it in for instance in the Autotrace Output where it represent the estimated number of rows that will flow out of a given execution plan step.
