3661
3658
return new_field;
3665
Create field for temporary table using type of given item.
3667
@param session Thread handler
3668
@param item Item to create a field for
3669
@param table Temporary table
3670
@param copy_func If set and item is a function, store copy of
3672
@param modify_item 1 if item->result_field should point to new
3673
item. This is relevent for how fill_record()
3675
If modify_item is 1 then fill_record() will
3676
update the record in the original table.
3677
If modify_item is 0 then fill_record() will
3678
update the temporary table
3679
@param convert_blob_length If >0 create a varstring(convert_blob_length)
3680
field instead of blob.
3688
static Field *create_tmp_field_from_item(Session *,
3689
Item *item, Table *table,
3690
Item ***copy_func, bool modify_item,
3691
uint32_t convert_blob_length)
3693
bool maybe_null= item->maybe_null;
3696
switch (item->result_type()) {
3698
new_field= new Field_double(item->max_length, maybe_null,
3699
item->name, item->decimals, true);
3703
Select an integer type with the minimal fit precision.
3704
MY_INT32_NUM_DECIMAL_DIGITS is sign inclusive, don't consider the sign.
3705
Values with MY_INT32_NUM_DECIMAL_DIGITS digits may or may not fit into
3706
Field_long : make them Field_int64_t.
3708
if (item->max_length >= (MY_INT32_NUM_DECIMAL_DIGITS - 1))
3709
new_field=new Field_int64_t(item->max_length, maybe_null,
3710
item->name, item->unsigned_flag);
3712
new_field=new Field_long(item->max_length, maybe_null,
3713
item->name, item->unsigned_flag);
3716
assert(item->collation.collation);
3718
enum enum_field_types type;
3720
DATE/TIME fields have STRING_RESULT result type.
3721
To preserve type they needed to be handled separately.
3723
if ((type= item->field_type()) == DRIZZLE_TYPE_DATETIME ||
3724
type == DRIZZLE_TYPE_TIME || type == DRIZZLE_TYPE_NEWDATE ||
3725
type == DRIZZLE_TYPE_TIMESTAMP)
3726
new_field= item->tmp_table_field_from_field_type(table, 1);
3728
Make sure that the blob fits into a Field_varstring which has
3731
else if (item->max_length/item->collation.collation->mbmaxlen > 255 &&
3732
convert_blob_length <= Field_varstring::MAX_SIZE &&
3733
convert_blob_length)
3734
new_field= new Field_varstring(convert_blob_length, maybe_null,
3735
item->name, table->s,
3736
item->collation.collation);
3738
new_field= item->make_string_field(table);
3739
new_field->set_derivation(item->collation.derivation);
3741
case DECIMAL_RESULT:
3743
uint8_t dec= item->decimals;
3744
uint8_t intg= ((Item_decimal *) item)->decimal_precision() - dec;
3745
uint32_t len= item->max_length;
3748
Trying to put too many digits overall in a DECIMAL(prec,dec)
3749
will always throw a warning. We must limit dec to
3750
DECIMAL_MAX_SCALE however to prevent an assert() later.
3755
signed int overflow;
3757
dec= cmin(dec, (uint8_t)DECIMAL_MAX_SCALE);
3760
If the value still overflows the field with the corrected dec,
3761
we'll throw out decimals rather than integers. This is still
3762
bad and of course throws a truncation warning.
3763
+1: for decimal point
3766
overflow= my_decimal_precision_to_length(intg + dec, dec,
3767
item->unsigned_flag) - len;
3770
dec= cmax(0, dec - overflow); // too long, discard fract
3772
len -= item->decimals - dec; // corrected value fits
3775
new_field= new Field_new_decimal(len, maybe_null, item->name,
3776
dec, item->unsigned_flag);
3781
// This case should never be choosen
3787
new_field->init(table);
3789
if (copy_func && item->is_result_field())
3790
*((*copy_func)++) = item; // Save for copy_funcs
3792
item->set_result_field(new_field);
3793
if (item->type() == Item::NULL_ITEM)
3794
new_field->is_created_from_null_item= true;
3833
Create field for temporary table.
3835
@param session Thread handler
3836
@param table Temporary table
3837
@param item Item to create a field for
3838
@param type Type of item (normally item->type)
3839
@param copy_func If set and item is a function, store copy of item
3841
@param from_field if field will be created using other field as example,
3842
pointer example field will be written here
3843
@param default_field If field has a default value field, store it here
3844
@param group 1 if we are going to do a relative group by on result
3845
@param modify_item 1 if item->result_field should point to new item.
3846
This is relevent for how fill_record() is going to
3848
If modify_item is 1 then fill_record() will update
3849
the record in the original table.
3850
If modify_item is 0 then fill_record() will update
3852
@param convert_blob_length If >0 create a varstring(convert_blob_length)
3853
field instead of blob.
3861
Field *create_tmp_field(Session *session, Table *table,Item *item,
3862
Item::Type type, Item ***copy_func, Field **from_field,
3863
Field **default_field, bool group, bool modify_item,
3864
bool, bool make_copy_field,
3865
uint32_t convert_blob_length)
3868
Item::Type orig_type= type;
3871
if (type != Item::FIELD_ITEM &&
3872
item->real_item()->type() == Item::FIELD_ITEM)
3875
item= item->real_item();
3876
type= Item::FIELD_ITEM;
3880
case Item::SUM_FUNC_ITEM:
3882
Item_sum *item_sum=(Item_sum*) item;
3883
result= item_sum->create_tmp_field(group, table, convert_blob_length);
3885
my_error(ER_OUT_OF_RESOURCES, MYF(ME_FATALERROR));
3888
case Item::FIELD_ITEM:
3889
case Item::DEFAULT_VALUE_ITEM:
3891
Item_field *field= (Item_field*) item;
3892
bool orig_modify= modify_item;
3893
if (orig_type == Item::REF_ITEM)
3896
If item have to be able to store NULLs but underlaid field can't do it,
3897
create_tmp_field_from_field() can't be used for tmp field creation.
3899
if (field->maybe_null && !field->field->maybe_null())
3901
result= create_tmp_field_from_item(session, item, table, NULL,
3902
modify_item, convert_blob_length);
3903
*from_field= field->field;
3904
if (result && modify_item)
3905
field->result_field= result;
3908
result= create_tmp_field_from_field(session, (*from_field= field->field),
3909
orig_item ? orig_item->name :
3912
modify_item ? field :
3914
convert_blob_length);
3915
if (orig_type == Item::REF_ITEM && orig_modify)
3916
((Item_ref*)orig_item)->set_result_field(result);
3917
if (field->field->eq_def(result))
3918
*default_field= field->field;
3922
case Item::FUNC_ITEM:
3924
case Item::COND_ITEM:
3925
case Item::FIELD_AVG_ITEM:
3926
case Item::FIELD_STD_ITEM:
3927
case Item::SUBSELECT_ITEM:
3928
/* The following can only happen with 'CREATE TABLE ... SELECT' */
3929
case Item::PROC_ITEM:
3930
case Item::INT_ITEM:
3931
case Item::REAL_ITEM:
3932
case Item::DECIMAL_ITEM:
3933
case Item::STRING_ITEM:
3934
case Item::REF_ITEM:
3935
case Item::NULL_ITEM:
3936
case Item::VARBIN_ITEM:
3937
if (make_copy_field)
3939
assert(((Item_result_field*)item)->result_field);
3940
*from_field= ((Item_result_field*)item)->result_field;
3942
return create_tmp_field_from_item(session, item, table,
3943
(make_copy_field ? 0 : copy_func),
3944
modify_item, convert_blob_length);
3945
case Item::TYPE_HOLDER:
3946
result= ((Item_type_holder *)item)->make_field_by_type(table);
3947
result->set_derivation(item->collation.derivation);
3949
default: // Dosen't have to be stored
3955
3697
Create a temp table according to a field list.
3957
3699
Given field pointers are changed to point at tmp_table for
added
removed
drizzled/table.cc
