Re: Disallow USING clause when altering type of generated column

On 22.08.24 09:59, Yugo NAGATA wrote:
>>> Although ERRCODE_INVALID_TABLE_DEFINITION is used for en error on  changing
>>> type of inherited column, I guess that is because it prevents from breaking
>>> consistency between inherited and inheriting tables as a result of the command.
>>> In this sense, maybe, ERRCODE_INVALID_COLUMN_DEFINITION is proper here, because
>>> this check is to prevent inconsistency between columns in a tuple.
>>
>> Yes, that was my thinking.  I think of ERRCODE_FEATURE_NOT_SUPPORTED as
>> "we could add it in the future", but that does not seem to apply here.
> 
> +				(errcode(ERRCODE_INVALID_TABLE_DEFINITION),
> +				 errmsg("cannot specify USING when altering type of generated column"),
> +				 errdetail("Column \"%s\" is a generated column.", colName)));
> 
> Do you thnik ERRCODE_INVALID_TABLE_DEFINITION is more proper than
> ERRCODE_INVALID_COLUMN_DEFINITION in this case?

COLUMN seems better here.

I copied TABLE from the "cannot alter system column" above, but maybe 
that is a different situation.