Cardinality estimation for optimization of recursive or iterative database queries by databases

A device that includes one or more processors that are configured to:

• estimate at least one result associated with execution of one or more iterations of the iterations of a database query of a database, wherein the database query requires multiple sub-queries to be executed as multiple iterations such that a result of a first one of the sub-queries is needed to be determined in a first iteration of the iterations in order to determine the result of a second one of the sub-quires in a second iteration of the iterations to be performed after the first iteration, and
• generate at least partly based on the at least one estimated result, a first execution plan for executing the one or more iterations.

A non-transitory computer readable storage medium that stores at least executable code for generating an execution plan for a database query of a database, wherein the database query requires multiple sub-queries to be executed as multiple iterations such that a result of a first one of the sub-queries is needed to be determined in a first iteration of the iterations in order to determine the result of a second one of the sub-quires in a second iteration of the iterations to be performed after the first iteration, and wherein the executable code includes:

• executable code for estimating at least one result associated with execution of one or more iterations of the iterations;
• and
• executable code for generating at least partly based on the at least one estimated result, a first execution plan for executing the one or more iterations.