# Business Data Model definition

Installing or updating the BDM implies to be logged in as Technical User, and to activate the maintenance mode.
To do so, log out and then log back in as the Technical User, whose credentials are set upon Bonita platform installation.

Only one Business Data Model (BDM) can be active at a time.
Make sure all artifacts enabled on the platform are compatible with the new BDM.

- ## Install Business Data Model

  ## Update Business Data Model

  Only available when the platform is under maintenance. Go to the "Platform maintenance" page to activate the maintenance mode.
  Before updating the BDM, access control file should be deleted.
  Installing Business Data Model
  BDM successfully updated.
  BDM access control file can now be installed.
  Make sure to deactivate the maintenance mode.
  An error occurred when deploying the BDM. Consult the logs for more information.
  File format may be invalid. For more information, check the log file.
  The BDM schema and data have been rolled-back to what they were before this update attempt.