It’s a post-installation configuration that hasn’t been done. The /etc/sudoers file has the following section in it:
# In the default (unconfigured) configuration, sudo asks for the root password. # This allows use of an ordinary user account for administration of a freshly # installed system. When configuring sudo, delete the two # following lines: Defaults targetpw # ask for the password of the target user i.e. root ALL ALL=(ALL) ALL # WARNING! Only use this together with 'Defaults targetpw'!
The administrator needs to edit /etc/sudoers and comment out the final two lines above, or remove them altogether. Once done, individual user accounts can be added as follows:
oracle ALL=(ALL) ALL norman ALL=(ALL) ALL
or groups can be given access as follows:
%dba ALL=(ALL) ALL %oinstall ALL=(ALL) ALL
Substituting the appropriate levels of commands and privileges of course!