On the left of the figure is a database cylinder icon labeled "Clustered Tables." On the top of the cylinder is a square. The square points to an icon that looks like a sheet of paper. The icon is labeled "Clustered Key department_id." The icon shows one set of rows for department 20 and another for department 110.

On the right of the figure is a database cylinder icon labeled "Unclustered Tables." On the top of the cylinder are two squares. The left square points to an icon that looks like a sheet of paper. The icon is labeled "employees" and contains rows for employees. The square on the right is labeled "departments" and shows one row for department 20 and another for department 110.