The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/12/notation.html
Description:
In section 3, Conventions, it would be helpful to point out that
parentheses, when used in the command descriptions, are to be interpreted as
literal required elements. As a newbie, the combination of {}, [], () was
already difficult to parse in command descriptions. Worse when the
Conventions element doesn't describe parentheses use in the definitions.
Here's a simple example where the parens are easy to miss, and it's not
otherwise clear what they do:
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT
EXISTS ] table_name ( [
{ column_name data_type [ COLLATE collation ] [ column_constraint [ ... ]
]
| table_constraint
| LIKE source_table [ like_option ... ] }
[, ... ]
] )
[ INHERITS ( parent_table [, ... ] ) ]
[ PARTITION BY { RANGE | LIST | HASH } ( { column_name | ( expression ) } [
COLLATE collation ] [ opclass ] [, ... ] ) ]
[ USING method ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]
I think a single sentence, like "parens () are required elements in the
syntax" would suffice.