Posting more details about your question will generally assist those trying to help you. In this case, reader may not be aware of what database server you're using. Also it would help to know if you're experiencing a specific issue.
With SQL Server you can use SQL Enterprise Manager to expand the size of the database. If you're concerned with database growth, you can refer to this KB article -kb.vmware.com/kb/1028356
You may also wish to review your Statistics settings within vCenter as that will have an impact on database growth.