Davi Arnaut wrote:
> # At a local mysql-5.1-bugteam repository of davi
>
> 3036 Davi Arnaut 2009-07-23
> Bug#45261: Crash, stored procedure + decimal
>
> The problem was that creating a DECIMAL column from decimal
> value could lead to a assertion as decimal values can have[...]
>
...from *a* decimal value...
...could lead to a failed assertion...
>
> This patch borrows code and ideas from Martin Hansson's patch.
> @ mysql-test/r/type_newdecimal.result
> Add test case result for Bug#45261. Also, update test case to
> reflect that a additive operation increases the precision of
>
...an additive operation...
> @ sql/item.cc
> The precision should only be capped when storing the value
> on a table. Also, this makes it impossible to calculate the
> integer part if Item::decimals (the scale) is larger then the
> precision.
>
...larger than...
> [...]
> === modified file 'sql/item.cc'
> --- a/sql/item.cc 2009-07-19 12:49:40 +0000
> +++ b/sql/item.cc 2009-07-23 22:11:01 +0000
> @@ -437,15 +437,13 @@ Item::Item(THD *thd, Item *item):
>
> uint Item::decimal_precision() const
> {
> +
Please document the fact that this function does not cap, as opposed to
Item::decimals. Preferrably, add cross-references between them.
> [...]
> +Field *Item::make_new_decimal_field() const
>
This method is truly brilliant and will make the code much more stable
by having it in one single place. But why is it in the Item class?
Wouldn't it be more natural in Field_new_decimal? Afaiu it doesn't
access any private data in Item.
Like:
static Field_new_decimal *Field::make_new_decimal_field(const Item *item)
Or even a new constructor Field_new_decimal(const Item *item)
A third option is just a standalone static function, although it's not
to my taste.
>
> +uint Item_func_get_user_var::decimal_precision() const
> +{
> + uint precision= max_length;
> + Item_result restype= result_type();
> +
> + /* Default to maximum as the precision is unknown a priori. */
> + if ((restype == DECIMAL_RESULT) || (restype == INT_RESULT))
> + precision= DECIMAL_MAX_PRECISION;
> +
> + return precision;
> +}
> +
> +
What made you add this?
Best Regards
Martin
