Sreeharsha Ramanavarapu 888fabd690 Bug #21143080: UPDATE ON VARCHAR AND TEXT COLUMNS PRODUCE ...

INCORRECT RESULTS

Issue:
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Updating varchar and text fields in the same update
statement can produce incorrect results. When a varchar
field is assigned to the text field and the varchar field
is then set to a different value, the text field's result
contains the varchar field's new value.

SOLUTION:
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Currently the blob type does not allocate space for the
string to be stored. Instead it contains a pointer to the
varchar string. So when the varchar field is changed as
part of the update statement, the value contained in the
blob also changes.

The fix would be to actually store the value by allocating
space for the blob's string. We can avoid allocating this
space when the varchar field is not being written into.

2015-07-16 07:56:39 +05:30

14 KiB

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