Commit 9e5691cb authored by unknown's avatar unknown
Browse files

Fix for bug #24558: Increasing decimal column length causes data loss 

Altering to a decimal field we get double value then store it 
that may cause data loss. 
Fix: use store_decimal() instead.



mysql-test/r/type_newdecimal.result:
  Fix for bug #24558: Increasing decimal column length causes data loss
    - test result.
mysql-test/t/type_newdecimal.test:
  Fix for bug #24558: Increasing decimal column length causes data loss
    - test case.
sql/field_conv.cc:
  Fix for bug #24558: Increasing decimal column length causes data loss
    - if target field's result type is DECIMAL_RESULT
      use store_decimal(val_decimal()) in order not to loss data.
parent d6bd171f

mysql-test/r/type_newdecimal.result

+8 −0
Original line number Diff line number Diff line
@@ -1423,3 +1423,11 @@ cast(19999999999999999999 as unsigned) 
18446744073709551615

Warnings:

Error	1292	Truncated incorrect DECIMAL value: ''

create table t1(a decimal(18));

insert into t1 values(123456789012345678);

alter table t1 modify column a decimal(19);

select * from t1;

a

123456789012345678

drop table t1;

End of 5.0 tests

mysql-test/t/type_newdecimal.test

+11 −0
Original line number Diff line number Diff line
@@ -1120,3 +1120,14 @@ drop table t1; 
#

select cast(19999999999999999999 as unsigned);



#

# Bug #24558: Increasing decimal column length causes data loss

#



create table t1(a decimal(18));

insert into t1 values(123456789012345678);

alter table t1 modify column a decimal(19);

select * from t1;

drop table t1;



--echo End of 5.0 tests

sql/field_conv.cc

+9 −0
Original line number Diff line number Diff line
@@ -337,6 +337,13 @@ static void do_field_real(Copy_field *copy) 
}





static void do_field_decimal(Copy_field *copy)

{

  my_decimal value;

  copy->to_field->store_decimal(copy->from_field->val_decimal(&value));

}





/*

  string copy for single byte characters set when to string is shorter than

  from string
@@ -581,6 +588,8 @@ void (*Copy_field::get_copy_func(Field *to,Field *from))(Copy_field*) 
    if (to->real_type() == FIELD_TYPE_BIT ||

        from->real_type() == FIELD_TYPE_BIT)

      return do_field_int;

    if (to->result_type() == DECIMAL_RESULT)

      return do_field_decimal;

    // Check if identical fields

    if (from->result_type() == STRING_RESULT)

    {