We can't have Item_trigger_field as aggregated object inside of
sp_instr_set_trigger_field class since in this case its destructor
will be called twice. So instead let us create this Item separately
and store pointer to it in instruction object.


sql/sp_head.cc:
  sp_instr_set_trigger_field:
    We can't have Item_trigger_field as aggregated object since in this
    case its destructor will be called twice, so let us store pointer
    to this Item (Another way to avoid this is to exclude this Item
    from free_list but this can't be done in elegant way in 5.0 and
    will also cause additional problems with Item::cleanup()).
sql/sp_head.h:
  sp_instr_set_trigger_field:
    We can't have Item_trigger_field as aggregated object since in this
    case its destructor will be called twice, so let us store pointer
    to this Item (Another way to avoid this is to exclude this Item
    from free_list but this can't be done in elegant way in 5.0 and
    will also cause additional problems with Item::cleanup()).
sql/sql_yacc.yy:
  We can't have Item_trigger_field as aggregated object inside of
  sp_instr_set_trigger_field class since in this case its destructor
  will be called twice. So instead let us create this Item separately
  and store pointer to it in instruction object.