A pseudo-column is an expression that you can use in the SELECT list of a SQL statement as if it were a column name, but that does not refer to a physical column in a table.
You can use pseudo-columns in SELECT output lists but also as the value of certain attributes in USoft Definer, in particular, in the Default Value attribute of Columns and Domains.
* SYSDATE is Oracle-only. For portability to other platforms, use $$CURRENTDATE$$ or the CURRENT_DATE SQL function instead.
Pseudo-columns are similar to SQL functions that take no arguments, such as TRANSACTION_DATE(). They differ from such functions in that the call syntax does not use empty parentheses ():
Another difference is that you can use a pseudo-column, but not a SQL function, as the Default Value attribute of a Column or Domain.