* Added Item_ref::set_properties
* Item_ref::Item_ref now expects to get in *item either
NULL - then fix_fields() will be called later or
ptr to Item it will refer to - then an equivalent of fix_fields() call is performed
The problem in 4.1 was the same as in 4.0 - fix_fields() not called for created Item_ref.
The fix is similar too - initialize Item_refs in ctor (but don't interfere with cases when
Item_ref is used by subselects).
out of order". (final version)
Now instead of binding Item_trigger_field to TABLE objects during
trigger definition parsing at table open, we perform pass through
special list of all such objects in trigger. This allows easily check
all references to fields in old/new version of row in trigger during
execution of CREATE TRIGGER statement (this is more courtesy for users
since we can't check everything anyway).
We also report that such reference is bad by returning error from
Item_trigger_field::fix_fields() method (instead of setup_field())
This means that if trigger is broken we will bark during trigger
execution instead of trigger definition parsing at table open.
(i.e. now we allow to open tables with broken triggers).
of <parameter> IS NULL":
we must not only set Item::null_value in Item_param, but implement
Item_param::is_null() to work well with IS NULL/IS NOT NULL clauses.
the result takes its charset/collation
attributes from the character string,
e.g. SELECT func(NULL, _latin2'string')
now returns a latin2 result. This is
done by introducing a new derivation
(aka coercibility) level DERIVATION_IGNORABLE,
which is used with Item_null.
2. 'Pure' NULL is now BINARY(0), not CHAR(0).
I.e. NULL is now more typeless.
FOUND is not a reserved keyword anymore
Added Item_field::set_no_const_sub() to be able to mark fields that can't be substituted
Added 'simple_select' method to be able to quickly determinate if a select_result is a normal SELECT
Note that the 5.0 tree is not yet up to date: Sanja will have to fix multi-update-locks for this merge to be complete
constant with a column. The string is converted into the column
character set. It conversion doesn't lose data, then operation
is possible. Otherwise, give an error, as it was earlier.
