diff options
Diffstat (limited to 'sql/item.h')
| -rw-r--r-- | sql/item.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/sql/item.h b/sql/item.h index 907b9ea5ad4..53db177b360 100644 --- a/sql/item.h +++ b/sql/item.h @@ -173,7 +173,17 @@ public: virtual cond_result eq_cmp_result() const { return COND_OK; } inline uint float_length(uint decimals_par) const { return decimals != NOT_FIXED_DEC ? (DBL_DIG+2+decimals_par) : DBL_DIG+8;} + /* + Returns true if this is constant (during query execution, i.e. its value + will not change until next fix_fields) and its value is known. + */ virtual bool const_item() const { return used_tables() == 0; } + /* + Returns true if this is constant but its value may be not known yet. + (Can be used for parameters of prep. stmts or of stored procedures.) + */ + virtual bool const_during_execution() const + { return (used_tables() & ~PARAM_TABLE_BIT) == 0; } virtual void print(String *str_arg) { str_arg->append(full_name()); } void print_item_w_name(String *); virtual void update_used_tables() {} @@ -318,6 +328,7 @@ public: class Item_param :public Item { public: + bool value_is_set; longlong int_value; double real_value; TIME ltime; @@ -336,6 +347,7 @@ public: item_result_type = STRING_RESULT; item_is_time= false; long_data_supplied= false; + value_is_set= 0; } enum Type type() const { return item_type; } double val(); @@ -363,6 +375,13 @@ public: String *query_val_str(String *str); enum_field_types field_type() const { return MYSQL_TYPE_STRING; } Item *new_item() { return new Item_param(pos_in_query); } + /* + If value for parameter was not set we treat it as non-const + so noone will use parameters value in fix_fields still + parameter is constant during execution. + */ + virtual table_map used_tables() const + { return value_is_set ? (table_map)0 : PARAM_TABLE_BIT; } void print(String *str) { str->append('?'); } }; |