On 2019-10-28 23:41, PG Doc comments form wrote:
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/12/ddl-generated-columns.html
Description:
https://www.postgresql.org/docs/12/ddl-generated-columns.html
In the below
"Consider the differences between a column with a default and a generated
column. The column default is evaluated once when the row is first inserted
if no other value was provided; a generated column is updated whenever the
row changes and cannot be overridden. A column default may not refer to
other columns of the table; a generation expression would normally do so. A
column default can use volatile functions, for example random() or functions
referring to the current time; this is not allowed for generated columns."
"a generation expression would normally do so" should be changed to "a
generated column" for easier reading
The current wording seems more precise. It's the expression that does
the referencing, not the column itself. There could be other things
attached to a column to could reference other things or not.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
