diff options
Diffstat (limited to 'sql/item.h')
| -rw-r--r-- | sql/item.h | 50 |
1 files changed, 48 insertions, 2 deletions
diff --git a/sql/item.h b/sql/item.h index 28b1f54add7..2f99034130a 100644 --- a/sql/item.h +++ b/sql/item.h @@ -370,6 +370,35 @@ public: } }; + +/* + This enum is used to report information about monotonicity of function + represented by Item* tree. + Monotonicity is defined only for Item* trees that represent table + partitioning expressions (i.e. have no subselects/user vars/PS parameters + etc etc). An Item* tree is assumed to have the same monotonicity properties + as its correspoinding function F: + + [signed] longlong F(field1, field2, ...) { + put values of field_i into table record buffer; + return item->val_int(); + } + + NOTE + At the moment function monotonicity is not well defined (and so may be + incorrect) for Item trees with parameters/return types that are different + from INT_RESULT, may be NULL, or are unsigned. + It will be possible to address this issue once the related partitioning bugs + (BUG#16002, BUG#15447, BUG#13436) are fixed. +*/ + +typedef enum monotonicity_info +{ + NON_MONOTONIC, /* none of the below holds */ + MONOTONIC_INCREASING, /* F() is unary and (x < y) => (F(x) <= F(y)) */ + MONOTONIC_STRICT_INCREASING /* F() is unary and (x < y) => (F(x) < F(y)) */ +} enum_monotonicity_info; + /*************************************************************************/ class sp_rcontext; @@ -431,6 +460,7 @@ public: FIELD_VARIANCE_ITEM, INSERT_VALUE_ITEM, SUBSELECT_ITEM, ROW_ITEM, CACHE_ITEM, TYPE_HOLDER, PARAM_ITEM, TRIGGER_FIELD_ITEM, DECIMAL_ITEM, + XPATH_NODESET, XPATH_NODESET_CMP, VIEW_FIXER_ITEM}; enum cond_result { COND_UNDEF,COND_OK,COND_TRUE,COND_FALSE }; @@ -506,6 +536,15 @@ public: virtual Item_result cast_to_int_type() const { return result_type(); } virtual enum_field_types field_type() const; virtual enum Type type() const =0; + + /* + Return information about function monotonicity. See comment for + enum_monotonicity_info for details. This function can only be called + after fix_fields() call. + */ + virtual enum_monotonicity_info get_monotonicity_info() const + { return NON_MONOTONIC; } + /* valXXX methods must return NULL or 0 or 0.0 if null_value is set. */ /* Return double precision floating point representation of item. @@ -596,6 +635,7 @@ public: TRUE value is true (not equal to 0) */ virtual bool val_bool(); + virtual String *val_nodeset(String*) { return 0; } /* Helper functions, see item_sum.cc */ String *val_string_from_real(String *str); String *val_string_from_int(String *str); @@ -771,7 +811,7 @@ public: // used in row subselects to get value of elements virtual void bring_value() {} - Field *tmp_table_field_from_field_type(TABLE *table); + Field *tmp_table_field_from_field_type(TABLE *table, bool fixed_length); virtual Item_field *filed_for_view_update() { return 0; } virtual Item *neg_transformer(THD *thd) { return NULL; } @@ -1200,6 +1240,10 @@ public: { return field->type(); } + enum_monotonicity_info get_monotonicity_info() const + { + return MONOTONIC_STRICT_INCREASING; + } Field *get_tmp_table_field() { return result_field; } Field *tmp_table_field(TABLE *t_arg) { return result_field; } bool get_date(TIME *ltime,uint fuzzydate); @@ -1933,7 +1977,7 @@ public: virtual Item *real_item() { return ref; } }; - +#ifdef MYSQL_SERVER #include "gstream.h" #include "spatial.h" #include "item_sum.h" @@ -1945,6 +1989,8 @@ public: #include "item_timefunc.h" #include "item_uniq.h" #include "item_subselect.h" +#include "item_xmlfunc.h" +#endif class Item_copy_string :public Item { |