This is an important excerpt from ReleaseNotes that came with bacula version
5.2.1 which explains updating database from 5.0.x version to 5.2.x. If you
are upgrading, it would be in your best interest to read and understand the
following:

New Catalog format in version 5.2.0 and greater
-----------------------------------------------
This release of Bacula uses a new catalog format. We provide a set of
scripts that permit to convert a 5.0.x (version 12) catalog to 5.2.1 (version
14).  The Bacula project rpm spec files have been modified to
detect the database change and do the upgrade for you.  We strongly
recommend that you save a copy of your existing database before upgrading
using rpms.

The simplest way to upgrade the database assuming you are building from
source (i.e. manually):
1. Stop any current version of Bacula from running.
2. Save a copy of your existing database.
3. Configure, build, and install the 5.2.1 version of Bacula
   Note the new ./configure options in the manuals see the link
   at the bottom of this file.
4. cd <your-scripts-installation-directory>
5. ./update_bacula_tables
6. If you have multiple catalogs, edit the update_bacula_tables
   script and put the name of another database, and then
   execute the script again. Repeat this until all Bacula
   catalogs have been updated.
7. Start the new Bacula.  If everything worked, it should
   not print any error messages.

If you start from scratch, you don't need to run the update_bacula_tables
script because the create_bacula_tables script automatically creates the new
table format.  However, if you are using a version of Bacula older than 5.0.0
(e.g.  3.0.3) then you need to run the update_bacula_tables script that will
be found in the <bacula>/src/cats directory after you run the ./configure
command.  As mentioned above, before running this script, please backup your
catalog database, and when you do running it, be sure shutdown Bacula and be
aware that running the script can take some time depending on your database
size.