Conditions Databases at FNAL

Conditions databases is an important class of database applications where the database is used to record the state of a set of quantities as a function of observation time. Conditions databases are used in Hight Energy Physics to record the state of the detector apparatus during data taking, and then to use the data during the event reconstruction and analysis phases. At FNAL, we have a set of 3 different conditions database products, Minerva Conditions DB, ConDB and UConDB, which cover the whole range of the use cases presented by the FNAL experiments. These products have common features such as conditions data representation model, data version control, ability to restore the database to a previous state, scalable web service data access interface. In the paper, we will present the common features of the products, common solutions used to build them and also the differences between the products and their target use cases.