Oracle Database 11g: Virtual database columns

Views in the Oracle database have several uses. You can use them to provide a view of data in different tables as a single object to query. You can use views to achieve a virtualization layer. Also views can be used to provide a user specific view of data. Implementing views however also have some challenges if you want to 'do it right'. You should consider grants to the table and the view. Maybe create synonyms. You should also consider what will happen if someone does access the underlying table since your data can now be queried from a different place (no single source of truth anymore). Do you want to have the view implement similar functionality as a table by providing an instead-of trigger when performing inserts on the view? Sometimes a view might seem too much for what you might want to accomplish. Suppose you want to add a single calculated field to a table. In this case there is a much easier solution than creating a view. A virtual column. The virtual column was introduced in Oracle Database 11g. In this blog post I'll give a simple minimal example of how you can use a virtual column and some things to mind when doing. Disclaimer: this code will not conform to many standards and is only meant as a minimal example.