The payroll database shares many data elements with the human resources database. Unfortunately, these two databases are usually maintained by different departments—accounting for the first and human resources for the second. Consequently, any employee who makes a change to one database, such as to an address field in the payroll system, must then walk to the human resources department to have the same information entered again for other purposes, such as benefits administration or a pension plan. Thus, there is an obvious inefficiency for the employee who must go to two departments for changes; another inefficiency is that the accounting and human resources staffs duplicate each other's data entry efforts.

An alternative is to tie the two databases together. This can be done by purchasing a software package that automatically consolidates the two databases into a single one. But the considerable cost of buying and implementing an entirely new software package will grossly exceed the cost savings obtained by consolidating the data.

A less costly approach is to create an interface between the two systems that automatically stores changes made to each database and updates the other one as a daily batch program. However, creating this interface may still be expensive, as it involves a reasonable amount of customized programming work. Consequently, this best practice is a costly proposition and is usually only done when both computer systems are being brought together for other reasons than to simply reduce data entry work.