Reliable population of the condition databases is critical for the correct
operation of the online selection as well as of the offline reconstruction and
analysis of data. We will describe here the system put in place in the CMS
experiment to populate the database and make condition data promptly available
both online for the high-level trigger and offline for reconstruction. The
system, designed for high flexibility to cope with very different data sources,
uses POOL-ORA technology in order to store data in an object format that best
matches the object oriented paradigm for \texttt{C++} programming language used
in the CMS offline software. In order to ensure consistency among the various
subdetectors, a dedicated package, PopCon (Populator of Condition Objects), is
used to store data online. The data are then automatically streamed to the
offline database hence immediately accessible offline worldwide. This mechanism
was intensively used during 2008 in the test-runs with cosmic rays. The
experience of this first months of operation will be discussed in detail.Comment: 15 pages, submitter to JOP, CHEP0