Environment variables
The Berkeley DB library uses the following environment variables:
DB_HOME
If the environment variable DB_HOME is set, it is used as part of File naming. Note: For the DB_HOME variable to take effect, either the DB_USE_ENVIRON or DB_USE_ENVIRON_ROOT flags must be specified to DB_ENV->open().
TMPDIR, TEMP, TMP, TempFolder
The TMPDIR, TEMP, TMP, and TempFolder environment variables are all checked as locations in which to create temporary files. See DB_ENV->set_tmp_dir() for more information.