Oracle Database - Rows (of Card as Cardinality for 9i)

Card Puncher Data Processing


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.

Documentation / Reference

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