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0 pointsmichael19993y ago0 comments

How would that work? Your schema allows an employee to be assigned to multiple departments, and the query must count them.

0 comments

It is also called Table Elimination if you want a google-able term.

Because of the foreign key, the query should reduce to "explain select count(*) from Department d;"

The schema only allows one employee per department, so there is no need to look up the employee table.

j / k navigate · click thread line to collapse

0 pointsmichael19993y ago0 comments

How would that work? Your schema allows an employee to be assigned to multiple departments, and the query must count them.

It is also called Table Elimination if you want a google-able term.

Because of the foreign key, the query should reduce to "explain select count(*) from Department d;"

The schema only allows one employee per department, so there is no need to look up the employee table.

j / k navigate · click thread line to collapse