Re: patch: to_string, to_array functions

some note

2010/7/12 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
> 2010/7/12 Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com>:
>> https://commitfest.postgresql.org/action/patch_view?id=300
>>
>> Why did you add to_string() and to_array() functions though we already
>> have string_to_array() and array_to_string() functions?  I prefer adding
>> three arguments version of string_to_array() instead of to_array().
>> Please notice me if you think to_string() and to_array() are better names
>> for the feature. For example, compatibility for other databases.
>>
>
> I prefere a new names  - because there are a new behave - with little
> bit better default handling of NULL values. string_to_array and
> array_to_string just ignore NULL values - what isn't correct behave.

it is related to time where pg arrays doesn't support a NULL. From 8.3
pg array can have a NULL values, but there wasn't any equal changes to
string_to_array and array_to_string functions - so these functions are
not "actual".

pavel

> Later we can mark these functions as deprecated and remove it. If I
> use current function, then we have to continue in current behave.
>
>> * string_to_array( str text, sep text, nullstr text DEFAULT NULL )
>> is compatible with the existing  string_to_array( str, sep ), and
>> "nullstr => 'NULL'" will be same as your to_array().
>>
>> * array_to_string( arr anyarray, sep text, nullstr text DEFAULT NULL )
>> is compatible with the existing  array_to_string(); separator also ignored
>> when nullstr is NULL. "nullstr => ''" (an empty string) will be same as
>> your to_array().
>>
>
> so reason for these new names are different default behave. And we
> can't to change of default behave of existing functions.
>
> Regards
>
> Pavel Stehule
>
>
>
>> --
>> Itagaki Takahiro
>>
>