diff options
Diffstat (limited to 'sql/field.cc')
| -rw-r--r-- | sql/field.cc | 195 |
1 files changed, 76 insertions, 119 deletions
diff --git a/sql/field.cc b/sql/field.cc index d1202657786..69fe192c1d1 100644 --- a/sql/field.cc +++ b/sql/field.cc @@ -1,4 +1,4 @@ -/* Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc. +/* Copyright 2000-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -2481,97 +2481,12 @@ Field_new_decimal::Field_new_decimal(uint32 len_arg, { precision= my_decimal_length_to_precision(len_arg, dec_arg, unsigned_arg); set_if_smaller(precision, DECIMAL_MAX_PRECISION); - DBUG_ASSERT(precision >= dec); DBUG_ASSERT((precision <= DECIMAL_MAX_PRECISION) && (dec <= DECIMAL_MAX_SCALE)); bin_size= my_decimal_get_binary_size(precision, dec); } -/** - Create a field to hold a decimal value from an item. - - @remark The MySQL DECIMAL data type has a characteristic that needs to be - taken into account when deducing the type from a Item_decimal. - - But first, let's briefly recap what is the new MySQL DECIMAL type: - - The declaration syntax for a decimal is DECIMAL(M,D), where: - - * M is the maximum number of digits (the precision). - It has a range of 1 to 65. - * D is the number of digits to the right of the decimal separator (the scale). - It has a range of 0 to 30 and must be no larger than M. - - D and M are used to determine the storage requirements for the integer - and fractional parts of each value. The integer part is to the left of - the decimal separator and to the right is the fractional part. Hence: - - M is the number of digits for the integer and fractional part. - D is the number of digits for the fractional part. - - Consequently, M - D is the number of digits for the integer part. For - example, a DECIMAL(20,10) column has ten digits on either side of - the decimal separator. - - The characteristic that needs to be taken into account is that the - backing type for Item_decimal is a my_decimal that has a higher - precision (DECIMAL_MAX_POSSIBLE_PRECISION, see my_decimal.h) than - DECIMAL. - - Drawing a comparison between my_decimal and DECIMAL: - - * M has a range of 1 to 81. - * D has a range of 0 to 81. - - There can be a difference in range if the decimal contains a integer - part. This is because the fractional part must always be on a group - boundary, leaving at least one group for the integer part. Since each - group is 9 (DIG_PER_DEC1) digits and there are 9 (DECIMAL_BUFF_LENGTH) - groups, the fractional part is limited to 72 digits if there is at - least one digit in the integral part. - - Although the backing type for a DECIMAL is also my_decimal, every - time a my_decimal is stored in a DECIMAL field, the precision and - scale are explicitly capped at 65 (DECIMAL_MAX_PRECISION) and 30 - (DECIMAL_MAX_SCALE) digits, following my_decimal truncation procedure - (FIX_INTG_FRAC_ERROR). -*/ - -Field_new_decimal * -Field_new_decimal::new_decimal_field(const Item *item) -{ - uint32 len; - uint intg= item->decimal_int_part(), scale= item->decimals; - - DBUG_ASSERT(item->decimal_precision() >= item->decimals); - - /* - Employ a procedure along the lines of the my_decimal truncation process: - - If the integer part is equal to or bigger than the maximum precision: - Truncate integer part to fit and the fractional becomes zero. - - Otherwise: - Truncate fractional part to fit. - */ - if (intg >= DECIMAL_MAX_PRECISION) - { - intg= DECIMAL_MAX_PRECISION; - scale= 0; - } - else - { - uint room= min(DECIMAL_MAX_PRECISION - intg, DECIMAL_MAX_SCALE); - if (scale > room) - scale= room; - } - - len= my_decimal_precision_to_length(intg + scale, scale, item->unsigned_flag); - - return new Field_new_decimal(len, item->maybe_null, item->name, scale, - item->unsigned_flag); -} - - int Field_new_decimal::reset(void) { store_value(&decimal_zero); @@ -6555,20 +6470,9 @@ uint Field::is_equal(Create_field *new_field) } -/* If one of the fields is binary and the other one isn't return 1 else 0 */ - -bool Field_str::compare_str_field_flags(Create_field *new_field, uint32 flag_arg) -{ - return (((new_field->flags & (BINCMP_FLAG | BINARY_FLAG)) && - !(flag_arg & (BINCMP_FLAG | BINARY_FLAG))) || - (!(new_field->flags & (BINCMP_FLAG | BINARY_FLAG)) && - (flag_arg & (BINCMP_FLAG | BINARY_FLAG)))); -} - - uint Field_str::is_equal(Create_field *new_field) { - if (compare_str_field_flags(new_field, flags)) + if (field_flags_are_binary() != new_field->field_flags_are_binary()) return 0; return ((new_field->sql_type == real_type()) && @@ -8334,7 +8238,7 @@ uint Field_blob::max_packed_col_length(uint max_length) uint Field_blob::is_equal(Create_field *new_field) { - if (compare_str_field_flags(new_field, flags)) + if (field_flags_are_binary() != new_field->field_flags_are_binary()) return 0; return ((new_field->sql_type == get_blob_type_from_length(max_data_length())) @@ -8838,38 +8742,81 @@ bool Field::eq_def(Field *field) /** + Compare the first t1::count type names. + + @return TRUE if the type names of t1 match those of t2. FALSE otherwise. +*/ + +static bool compare_type_names(CHARSET_INFO *charset, TYPELIB *t1, TYPELIB *t2) +{ + for (uint i= 0; i < t1->count; i++) + if (my_strnncoll(charset, + (const uchar*) t1->type_names[i], + t1->type_lengths[i], + (const uchar*) t2->type_names[i], + t2->type_lengths[i])) + return FALSE; + return TRUE; +} + +/** @return returns 1 if the fields are equally defined */ bool Field_enum::eq_def(Field *field) { + TYPELIB *values; + if (!Field::eq_def(field)) - return 0; - return compare_enum_values(((Field_enum*) field)->typelib); -} + return FALSE; + values= ((Field_enum*) field)->typelib; -bool Field_enum::compare_enum_values(TYPELIB *values) -{ + /* Definition must be strictly equal. */ if (typelib->count != values->count) return FALSE; - for (uint i= 0; i < typelib->count; i++) - if (my_strnncoll(field_charset, - (const uchar*) typelib->type_names[i], - typelib->type_lengths[i], - (const uchar*) values->type_names[i], - values->type_lengths[i])) - return FALSE; - return TRUE; + + return compare_type_names(field_charset, typelib, values); } +/** + Check whether two fields can be considered 'equal' for table + alteration purposes. Fields are equal if they retain the same + pack length and if new members are added to the end of the list. + + @return IS_EQUAL_YES if fields are compatible. + IS_EQUAL_NO otherwise. +*/ + uint Field_enum::is_equal(Create_field *new_field) { - if (!Field_str::is_equal(new_field)) - return 0; - return compare_enum_values(new_field->interval); + TYPELIB *values= new_field->interval; + + /* + The fields are compatible if they have the same flags, + type, charset and have the same underlying length. + */ + if (new_field->field_flags_are_binary() != field_flags_are_binary() || + new_field->sql_type != real_type() || + new_field->charset != field_charset || + new_field->pack_length != pack_length()) + return IS_EQUAL_NO; + + /* + Changing the definition of an ENUM or SET column by adding a new + enumeration or set members to the end of the list of valid member + values only alters table metadata and not table data. + */ + if (typelib->count > values->count) + return IS_EQUAL_NO; + + /* Check whether there are modification before the end. */ + if (! compare_type_names(field_charset, typelib, new_field->interval)) + return IS_EQUAL_NO; + + return IS_EQUAL_YES; } @@ -9622,7 +9569,7 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type, } if (length == 0) - fld_length= 0; /* purecov: inspected */ + fld_length= NULL; /* purecov: inspected */ } sign_len= fld_type_modifier & UNSIGNED_FLAG ? 0 : 1; @@ -9774,8 +9721,7 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type, case MYSQL_TYPE_TIMESTAMP: if (fld_length == NULL) { - /* Compressed date YYYYMMDDHHMMSS */ - length= MAX_DATETIME_COMPRESSED_WIDTH; + length= MAX_DATETIME_WIDTH; } else if (length != MAX_DATETIME_WIDTH) { @@ -9839,7 +9785,7 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type, sql_type= MYSQL_TYPE_NEWDATE; /* fall trough */ case MYSQL_TYPE_NEWDATE: - length= 10; + length= MAX_DATE_WIDTH; break; case MYSQL_TYPE_TIME: length= 10; @@ -9920,6 +9866,17 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type, DBUG_RETURN(TRUE); } + switch (fld_type) { + case MYSQL_TYPE_DATE: + case MYSQL_TYPE_NEWDATE: + case MYSQL_TYPE_TIME: + case MYSQL_TYPE_DATETIME: + case MYSQL_TYPE_TIMESTAMP: + charset= &my_charset_bin; + flags|= BINCMP_FLAG; + default: break; + } + DBUG_RETURN(FALSE); /* success */ } |