Thread: Docs for Generated Columns

Hi,

while reading though the docs of the upcoming pg12 features, I stumbled upon some wording regarding generated columns:

both in create_table.sgml [1] and create_foreign_table.sgml [2] the paragraph for the GENERATED ALWAYS AS clause is
introducedwith  

> This clause creates the column as a generated column. The column cannot be written to, and when read it will be
computedfrom the specified expression. 

To me this sounds confusing, if not wrong. Till v8 of the patch were STORED and VIRTUAL generated columns were
describedafterwards this was less obvious but now with only STORED it sounds like a reference to the VIRTUAL variant.
Notbeing I native english speaker I'm restrained to send a patch but may I suggest the following for discussion: 

  The column cannot be written to, and when read the result of the specified expression will be returned.

Best regards
Tobias Bussmann

[1]: https://www.postgresql.org/docs/devel/sql-createtable.html
[2]: https://www.postgresql.org/docs/devel/sql-createforeigntable.html

On 5/23/19 5:50 PM, Tobias Bussmann wrote:
> while reading though the docs of the upcoming pg12 features, I
> stumbled upon some wording regarding generated columns: both in
> create_table.sgml [1] and create_foreign_table.sgml [2] the paragraph
> for the GENERATED ALWAYS AS clause is introduced with
>> This clause creates the column as a generated column. The column
>> cannot be written to, and when read it will be computed from the
>> specified expression.

> To me this sounds confusing, if not wrong. Till v8 of the patch were
> STORED and VIRTUAL generated columns were described afterwards this
> was less obvious but now with only STORED it sounds like a reference
> to the VIRTUAL variant.

No doubt this is flat out wrong.


> Not being I native english speaker I'm restrained to send a patch but
> may I suggest the following for discussion:

> The column cannot be written to, and when read the result of the
> specified expression will be returned.


That sounds reasonable to me.

Joe

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On 24.05.2019 14:21, Joe Conway <mail@joeconway.com> wrote:
>> The column cannot be written to, and when read the result of the
>> specified expression will be returned.
> That sounds reasonable to me.

Thank you for confirmation and review. Please find attached my proposed little doc patch for this issue.

Tobias

On 2019-05-26 16:42, Tobias Bussmann wrote:
> On 24.05.2019 14:21, Joe Conway <mail@joeconway.com> wrote:
>>> The column cannot be written to, and when read the result of the
>>> specified expression will be returned.
>> That sounds reasonable to me.
> 
> Thank you for confirmation and review. Please find attached my proposed little doc patch for this issue.

committed

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