Physical and logical databases

It is important as a consultant to understand how the database is actually created. From the system side, when you access the database, you generally see only the logical database. Say, you have a NAV database of size 500 GB. Now in reality, it might not be a single stack of 500 GB. This can be because of different factors. As the database size increases, we do not replace the whole hardware because doing that can be an expensive and time-consuming task. So we end up adding extra memory physical disks to get the required storage capacity.

The following diagram illustrates how the logical space can be realized by using totally different physical hardware memory disks. The physical disks can also be in different places yet supporting the same logical database system:

Besides this, there is logical structure inside the database as well. A logical divide means further categorization of the database so that we can place our record in a DB pattern. To achieve a logical...