Re: ERXBatchingDisplayGroup, Oracle and Sorting Null Values **FIXED**
Re: ERXBatchingDisplayGroup, Oracle and Sorting Null Values **FIXED**
- Subject: Re: ERXBatchingDisplayGroup, Oracle and Sorting Null Values **FIXED**
- From: David Avendasora <email@hidden>
- Date: Fri, 8 Jan 2010 14:57:17 -0500
Is there general consensus that the way sorting _should_ work is that null is considered to be less-than non-null?
Dave
On Jan 8, 2010, at 2:42 PM, Chuck Hill wrote:
> I'd guess that few of us use Oracle. And few of those use ERXBatchingDisplayGroup with a column containing nulls. IOW, you are just lucky.
>
>
> Chuck
>
>
>
> On Jan 8, 2010, at 10:37 AM, David Avendasora wrote:
>
>> Before I submit the patch, am I really the only one to have run into this with Oracle? Am I missing something fundamental?
>>
>> Dave
>>
>> On Jan 8, 2010, at 12:28 PM, David Avendasora wrote:
>>
>>> Hi Mike,
>>>
>>> Almost perfect. Following your example, here's what I came up with: (patch to follow in Jira)
>>>
>>> @Override
>>> public void addOrderByAttributeOrdering(EOSortOrdering sortOrdering) {
>>> super.addOrderByAttributeOrdering(sortOrdering);
>>> if (sortOrdering.selector() == EOSortOrdering.CompareCaseInsensitiveDescending
>>> || sortOrdering.selector() == EOSortOrdering.CompareDescending) {
>>> _orderByString().append(" NULLS LAST"); // Oracle's Default
>>> } else {
>>> _orderByString().append(" NULLS FIRST");
>>> }
>>> }
>>>
>>> Dave
>>>
>>> On Jan 8, 2010, at 10:36 AM, Mike Schrag wrote:
>>>
>>>> maybe try something like (completely untested):
>>>>
>>>> public void addOrderByAttributeOrdering(EOSortOrdering sortOrdering) {
>>>> super. addOrderByAttributeOrdering(sortOrdering);
>>>> _orderByString().append(" NULLS FIRST");
>>>> }
>>>>
>>>> On Jan 8, 2010, at 10:20 AM, David Avendasora wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> This has taken me a while to track down, and I just want to make sure I've figured it out correctly, and if so, what the possible solutions are.
>>>>>
>>>>> Oracle sorts null values to the end, so ORDER BY FIRST_NAME returns:
>>>>>
>>>>> Anjo
>>>>> Chunk
>>>>> Mike
>>>>> Null
>>>>>
>>>>> EOSortOrdering sorts null values to the begining, so NAME.ascs() returns:
>>>>> Null
>>>>> Anjo
>>>>> Chunk
>>>>> Mike
>>>>>
>>>>> Which does some really crazy things to ERXBatchingDisplayGroup.
>>>>>
>>>>> Let's say I have 100 rows in the DG. All the Name attributes are null, except for those three.
>>>>>
>>>>> First the DB selects all the records and sorts them with nulls last, then gets the first 10 ids :
>>>>>
>>>>> select * from (select NAME, rownum eo_rownum from (SELECT t0.NAME FROM PEOPLE t0 ORDER BY t0.NAME ASC)) where eo_rownum between 1 and 10
>>>>>
>>>>> The results will be: Anjo, Chunk, Mike, null, null, null, null, null, null, null.
>>>>>
>>>>> Then EOF sorts the array again, so the DG displays: null, null, null, null, null, null, null, Anjo, Chunk, Mike and all the subsequent batches will be full of nulls.
>>>>>
>>>>> If this interpretation is correct, am I the first to run into this with Oracle?
>>>>>
>>>>> I've been digging through the EROraclePlugin, and I figured adding this to the EROracleExpression class would fix it, but it doesn't:
>>>>>
>>>>> @Override
>>>>> protected void appendItemToOrderByString(String sqlString) {
>>>>> appendItemToListString(sqlString + " NULLS FIRST",
>>>>> _orderByString());
>>>>> }
>>>>>
>>>>> Anyone have any other suggestions?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Dave
>>>>> _______________________________________________
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> Chuck Hill Senior Consultant / VP Development
>
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