Introduction

The fundamental function of the calibration database is to serve the various sets of calibration constants necessary to reconstruct data from a particle physics detector with multiple quasi-independent sub-detectors. Each sub-detector will have its own unique needs for the form and function of constants. These constants will change as a function of run number, and the run number boundaries between changes in the constants will be different for different sub-detectors. In addition the procedure for obtaining the constants may change over the life of the experiment; the definition of "the best constants" for a given run will be a function of time. These points in time when new constants supersede old will also vary for different sub-detectors.