Better technique null values

Which is better, from the following?
if method
String studentIdParam = request.getParameter("studentId");
long studentId = 0
if(studentIdParam !=null)
studentId = Long.parseLong(studentIdParam);exception method
long studentId = 0;
try{
studentId = Long.parseLong(request.getParameter("studentId");
}Exception e{}

aksarben wrote:
If a null student ID is harmless, i might be tempted to go with Door number 1.In both options, studentID is declared 0 (which may/may not change depending on the request parameter), so if a studentID of 0 is harmless then sure.
Personally, I wouldn't use either. I would either declare the long studentID inside the try/catch block, or if it needed to be in a bigger scope, I'd declare it outside but not initialize it and do my null checks as needed.

Similar Messages

Index (or not) for excluding NULL values in a query

Hello,
I have table that can become very large. The table has a varchar2 column (let's call it TEXT) that can contain NULL values. I want to process only the records that have a value (NOT NULL). Also, the table is continuously expanded with newly inserted records. The inserts should suffer as little performance loss as possible.
My question: should I use an index on the column and if so, what kind of index?
I have done a little test with a function based index (inspired by this Tom Kyte article: http://tkyte.blogspot.com/2006/01/something-about-nothing.html):
create index text_isnull_idx on my_table(text,0);
I notice that if I use the clause WHERE TEXT IS NULL, the index is used. But if I use a clause WHERE TEXT IS NOT NULL (which is the clause I want to use), a full table scan is performed. Is this bad? Can I somehow improve the speed of this selection?
Thanks in advance,
Frans

I build a test case with very simple table with 2 columns and it shows that FTS is better than index access even when above ratio is <= 0.01 (1%):
DROP TABLE T1;
CREATE TABLE T1
           C1 VARCHAR2(100)
          ,C2 NUMBER
INSERT INTO T1 (SELECT TO_CHAR(OBJECT_ID), ROWNUM FROM USER_OBJECTS);
BEGIN
     FOR I IN 1..100 LOOP
          INSERT INTO T1 (SELECT NULL, ROWNUM FROM USER_OBJECTS);
     END LOOP;
END;
CREATE INDEX T1_IDX ON T1(C1);
ANALYZE TABLE T1 COMPUTE STATISTICS
     FOR TABLE
     FOR ALL INDEXES
     FOR ALL INDEXED COLUMNS
SET AUTOTRACE TRACEONLY
SELECT
          C1, C2
     FROM T1 WHERE C1 IS NOT NULL;
3864 rows selected.
real: 1344
Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=59 Card=3864 Bytes=30912)
   1    0   TABLE ACCESS (FULL) OF 'T1' (Cost=59 Card=3864 Bytes=30912)
Statistics
          0 recursive calls
          0 db block gets
       2527 consistent gets
       3864 rows processed
BUT
SELECT
     --+ FIRST_ROWS
          C1, C2
     FROM T1 WHERE C1 IS NOT NULL;
3864 rows selected.
real: 1296
Execution Plan
   0      SELECT STATEMENT Optimizer=HINT: FIRST_ROWS (Cost=35 Card=3864 Bytes=30912)
   1    0   TABLE ACCESS (BY INDEX ROWID) OF 'T1' (Cost=35 Card=3864 Bytes=30912)
   2    1     INDEX (FULL SCAN) OF 'T1_IDX' (NON-UNIQUE) (Cost=11 Card=3864)
Statistics
          0 recursive calls
          0 db block gets
       5052 consistent gets
       3864 rows processed
and just for comparison:
SELECT * FROM T1 WHERE C1 IS NULL;
386501 rows selected.
real: 117878
Execution Plan
   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=59 Card=386501 Bytes=3092008)
   1    0   TABLE ACCESS (FULL) OF 'T1' (Cost=59 Card=386501 Bytes=3092008)
Statistics
          0 recursive calls
          0 db block gets
     193850 consistent gets
     386501 rows processedHence you have to benchmark you queries with and w/o index[es]

Distinguishing between empty string and null values

hi all,
I am using an ODBC connection to connect my java app to database using JDBCODBC driver. I have 2 columns 'aColumn' and 'bColumn' in my table, both allow null values. I have one row in it, which has null value in aColumn and empty string in bColumn. I retrieve this row's data and assign it to 2 columns : 'aColumnVar' and 'bColumnVar' respectively. I find out that both 'aColumnVar' and 'bColumnVar' variables has null values (although bColumnVar should has an empty string as its value). Now my ODBC connection Data Source has the option "Use ANSI nulls, paddings, and warnings" ON. I turn it off and try again. This time both 'aColumnVar' and 'bColumnVar' variables has empty string as values (although aColumnVar should has null as its value).
How can I make sure that i can get the data exactly as it is in the database in my variables?
Thanks

there is a wasNull() method on ResultSet. After you
have obtained the value of a column e.g. by calling a
method like getString you can call wasNull and if it
returns true then the value on the database is null.
Check the java docs, it might explain it better
http://java.sun.com/j2se/1.4.1/docs/api/java/sql/Result
et.html#wasNull()I am using MS SQL Server 7.0 under Windows NT 4.0 with JDK 1.2. My ODBC connection Data Source has to have the option "Use ANSI nulls, paddings, and warnings" ON.
I try the wasNull() method but it is doing the same thing i.e. telling me that a column is null when in database it is null (right); and a column is null when in database it is an empty string (wrong). I suspect it is something to do with the JDBC-ODBC driver I am using.

Null value handling in LOVs

Has null value handling improved any in HTMLDB 1.6?
If my LOV has "Display null"=Yes (default null value is %null%) and I need to pass in a database NULL to a After Submit process, I need to do add a After Submit computation for each of these LOVs with something like
CASE WHEN :P1_ITEM='%null%' THEN NULL ELSE :P1_ITEM END
I have a couple dozen LOVs on a page and it is getting tiring to go and do this on each and every one!
Is there a better way?
Thanks

Hi Patrick,
we are currently moving over to Apex 4.02 and are doing some smoke tests on our existing apps.
I have come across an issue with your generic solution to the %null% issue above (incidently, for a long time it's the first piece of code I include when I start a new app... thank you!)
We found that a lot of our SQL Query (PL/SQL function body returning SQL query) reports were failing due to the session state of the LOVs still having a session state of %null% even after the RemoveNulls application process had run.
After debugging your generic process we found that the LOV_NULL_VALUE in the APEX_APPLICATION_PAGE_ITEMS view has changed from NULL to '%null%'.
so the fix was as below:-
BEGIN
    FOR rItem IN
      ( SELECT ITEM_NAME
          FROM APEX_APPLICATION_PAGE_ITEMS
         WHERE APPLICATION_ID   = TO_NUMBER(:APP_ID)
           AND PAGE_ID          IN (TO_NUMBER(:APP_PAGE_ID), 0)
           AND LOV_DISPLAY_NULL = 'Yes'
           AND LOV_DEFINITION   IS NOT NULL
-- change here
           AND LOV_NULL_VALUE = '%null' || '%'
    LOOP
        IF V(rItem.ITEM_NAME) = '%null' || '%'
        THEN
            Apex_Util.set_session_state(rItem.ITEM_NAME, NULL);
        END IF;
    END LOOP;
END;Cheers,
Gus.. (always a fan of your work!)

Null value for int and datetime date type in xml schema

hi:
I am embarrassed by a qustion in xml schema; i defined a xml schema file like
this:
<elementFormDefault="qualified" attributeFormDefault="qualified">
<xs:element name="test">
<xs:annotation>
<xs:documentation>Comment describing your root element</xs:documentation>
</xs:annotation>
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string"/>
<xs:element name="password" type="xs:string" nillable="true"/>
<xs:element name="user" type="xs:int" nillable="true"/>
<xs:element name="s_time" type="xs:dateTime"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
and I send this file to workflow clientrequest() node, I wanted to receive data
in this schema file.but when i send null value to the element "user" and "s_time"
in workshop test tool(test soap),and use function in xmlbean like isNilUser or
isNilStime, one error occur.
I don't kown why, I had to ask the engineer of bea in china, one told me a bug.
is that true?

Visakh16 I cant agree more with you on it, it is good but in production u cant have them change maxrows. I think
Patrick Hurst is a better option. debug the package have it running and move up
Please mark as helpful and propose as answer if you find this as correct!!! Thanks,Dia Agha .
Hmm..Why do you need to change it in production?
What I suggested was to tweak the setting in dev machine so that it interprets the Excel file datatypes correctly when doing development. Once mapping is set correctly then it will work fine when in production or in any other environment. The tweaking is
just to make sure it interprets the datatype correctly at design time and has nothing to do with production deployment
Please Mark This As Answer if it solved your issue
Please Mark This As Helpful if it helps to solve your issue
Visakh
My MSDN Page
My Personal Blog
My Facebook Page

Null value in poplist

Hi,
I'm using forms6i, I'm having a poplist in my form, which i populate in when-new-form-instance.
So when i open the form, and try to select one value, i'm seeing one null value, and if i select one value from list and again try to change the value then the previous null value is gone.
So to avoid that in when-new-form-instance itself , i assigned one value to the poplist using Get_List_Element_Value.
But the problem is since i'm assigning value, the form goes in insert status, and so even if i dont enter any valuees and try to exit, it is asking Close Form? (because i have few non-null items also).
How can i get one safe solution (like as it work when we assign some static values to the poplist).
ie i dont want nulls to be seen iin the list also i dont want the close form? message
I tried one solun by setting the form status as new again in w-n-f-i. But since i have multirecord block, this problem comes with every record.
Please suggest one better solution

Hi Divya
why don't u try putting the same code of the w-n-f-i in when-validate-record or when-new-record-instance may be it work...
if not working pls share us the code what about an example:
declare
rg_name varchar2(40):='r_area_record1';
rg_id Recordgroup;
LIST_ID ITEM;
errcode NUMBER;
begin
rg_id:=Find_Group(rg_name);
if Id_null(rg_id)
then
rg_id :=Create_group_from_query(rg_name,
'select VC_ID , research_area from research_info
where proff_id= 9');
LIST_ID:=FIND_ITEM('TRY_BLOCK.TRY');
end if;
errcode:=populate_group(rg_id);
POPULATE_LIST(LIST_ID,RG_ID);
end; Regards,
Abdetu...
Edited by: Abdetu on Jan 27, 2011 2:30 AM

NULL Value in CLOB

Hi,
I am calling a stored procedure with CLOB parameter and I need to pass NULL value to CLOB paramter through ADO in VC++.
My problem is when I send CLOB value as NULL a single Digit Binary value is inserted.I am using SAFEARRAY and AppendChunk mechanism to create CommandParameters for Storedprocedure.
Any suggestion where i am going wrong...
SDG

I've never worked with CLOB's before. But, I've put a great deal of effort into trying to pass a null value to Oracle from ADO. Finally, I just gave up and simply specified other fields but not the one I wanted to be null. The end result is that the field contains null after the row is inserted. I realize you'd like a better answer, but, I thought I'd throw in my $0.02 anyhow.
Good luck.

Null Value in List of Values

Hi,
I have done a search on the threads with null value in LOVs but it has not helped me understand the situation any better.
currently i have two select lists on a form, customer and project.
customers have many projects - and the only mandatory field on this form is customer - a project does NOT have to be selected - however, when the project is selected - i wish to validate the two items so that the selected project belongs to the selected customer.
i have been able to do this to some degree using the validation by doing a select exists, however, when the project select list has no item set (is NULL) then the validation function fails.
the validation function works fine when the project is not null. i basically want to force to to turn the %null% into actual null so i can use the is null function or something along those lines.
i have tried writing a calculation that does the actual translaction after submit, however, i think i'm writing the code wrong
can anyone lend a hand? or suggest some other alternatives?
Many thanks!

Hi Scott,
Thanks for your reply
I have tried to enter the item level validation as an exists query as follows :-
select project_name from project where (:p2_project_id = '%null'||'%') OR (project_id = :p2_project_id AND customer_id = :p2_customer_id)
:p2_project_id and :p2_customer_id are both select lists.
it checks to see whether the :p2_project_id is null if it is, then no checking is necessary - otherwise, the project selected must have the correct customer selected.
i can check that the project has a matching customer selected when project is not null, but when it is null i get the problem
select project_name from project where (:p2_project_id = '%null'||'%') OR (project_id = :p2_project_id AND customer_id = :p2_customer_id): ORA-01722: invalid number
any ideas?
cheers
leonard

Is it possible to filter a table for NULL values in a column? (11g)

I am using the out-of-the box table filtering provided by ADF Faces RC, but cannot figure out how to filter on Null value that are in the table.
I have tried "IS NULL" and "= NULL", but nothing works.
I have a backing bean that intercepts the filtered values before the filter is applied, and I can't set it there either.
Does anyone know how this is accomplished?

No, it is not. Worse, many people will view this in any old PDF viewer, most of which won't have overprint preview at all.
You need to send very clear instructions about this, with specific screen shots - or better, avoid tools and constructions that require it. Probably some wording about "need to view with suitable professional tools" will make the message more palatable.

Checking for null value in arraylist

Hi
i have an excel file which i i am reading into an arraylist row by row but not necesarrily that all columns in the row mite be filled. So how do i check for null values in the array list.
try
                    int cellCount = 0;
                    int emptyRow = 0;
                    HSSFWorkbook workbook = new HSSFWorkbook(new FileInputStream(file));
                    HSSFSheet sheet = workbook.getSheetAt(0);
                    Iterator rows = sheet.rowIterator();
                    myRow = new ArrayList();
                    int r = 1;
                         while (rows.hasNext())
                              System.out.println("Row # " + r);
                              HSSFRow row = (HSSFRow) rows.next();
                              Iterator cells = row.cellIterator();
                              cellCount = 0;
                              boolean isValid = false;
                              while (cells.hasNext())
                                   HSSFCell cell = (HSSFCell) cells.next();
                                   switch (cell.getCellType())
                                        case HSSFCell.CELL_TYPE_NUMERIC:
                                             double num = cell.getNumericCellValue();
                                             DecimalFormat pattern = new DecimalFormat("###,###,###,###");
                                             NumberFormat testNumberFormat = NumberFormat.getNumberInstance();
                                             String mob = testNumberFormat.format(num);
                                             Number n = null;
                                             try
                                                  n = pattern.parse(mob);
                                             catch ( ParseException e )
                                                  e.printStackTrace();
                                             System.out.println(n);
                                             myRow.add(n);
                                             //myRow.add(String.valueOf(cell.getNumericCellValue()).trim());
                                             //System.out.println("numeric: " +cell.getNumericCellValue());
                                             break;
                                        case HSSFCell.CELL_TYPE_STRING:
                                             myRow.add(cell.getStringCellValue().trim());
                                             System.out.println("string: " + cell.getStringCellValue().trim());
                                             break;
                                        case HSSFCell.CELL_TYPE_BLANK:
                                             myRow.add(" ");
                                             System.out.println("add empty:");
                                             break;
                                   } // end switch
                                   cellCount++;
                              } // end while
                              r++;
                         }// end while
               } myRow is the arrayList i am adding the cells of the excel file to. I have checked for blank spaces in my coding so please help with how to check for the black spaces that has been added to my arraylist.
I have tried checking by looping through the ArrayList and then checking for null values like this
if(myRow.get(i)!=null)
// do something
// i have tried this also
if(myRow.get(i)!="")
//do something
}Edited by: nb123 on Feb 3, 2008 11:23 PM

From your post I see you are using a 3rd party package to access the Excel SpreadSheets, you will have to look in your API for you 3rd party package and see if there is a method that will identify a blank row, if there is and it does not work, then you have to take that problem up with them. I know this is a pain, but it is the price we pay for 3rd party object use.
In the mean time, you can make a workaround by checking every column in your row and seeing if it is null, or perhaps even better: check and see if the trimmed value of each cell has a lenth of 0.

Null value in Nested table of nested table for xml guru Steve Muench

The procedure I am using takes xml document with nested levels and insert into single table using DBMS_XMLSave.insertXML.
I am able to insert into table without any error message but when I am selecting row from table, it is showing null values in all the column of nested table's inner nested table.
When I am removing nested table's nested table by replacing with object type, it is showing data of object type for the first occurance and ignoring the rest nested occurance.
Help is greatly appreciated.
Below is the sql I used to create objects and table:-
Create or Replace Type addressType as Object
Line_one     varchar2(40),
Line_two     varchar2(40),
City          Varchar2(30),
State          Varchar2(2),
zip          Varchar2(10)
Create or Replace Type ce_reqType as Object
Status               varchar2(25),
Status_date          Date,
type_code          Varchar2(25),
review_begin_date     Date,
assigned_review_date     date
Create or Replace type ce_reqListType
as table of ce_reqType;
Create or Replace Type LicenseType as Object
type_code          Varchar2(10),
license_number          Varchar2(16),
ce_requirements      ce_reqListType
Create or Replace type LicenseListType
as table of LicenseType;
Create table IndividualType
individual_id          Number(9),
social_security_number Varchar2(9),
Last_name          varchar2(40),
First_name          Varchar2(40),
Middle_name          Varchar2(40),
Birth_date          Date,
address          addressType,
Licenses          LicenseListType
nested table licenses store as licensestab
(nested table ce_requirements store as lic_ce_reqtab);

Maddy wrote:
dbms_output.put_line('The count is '||bookset.count); --> I can see COUNT =1 (why)Because instead of adding an element to bookset collectionto are assigning (ergo replacing) it a collection containing last fetched book. Use:
declare
    bookset book_table;
    ln_cnt pls_integer;
begin
    bookset := book_table(book_obj('madhu','kongara','sudhan'));
    dbms_output.put_line('The count is '||bookset.count); --> I can see COUNT =1
    bookset := book_table(); --> Assigning back to NULL.
    dbms_output.put_line('The count is '||bookset.count); --> I can see count as 0
    for rec in (select * from book) loop --> Now Looping two times.
      dbms_output.put_line(' name > '||rec.name);
      bookset.extend;
      bookset(bookset.count) := book_obj(rec.name, rec.author, rec.abstract);
    end loop;
    dbms_output.put_line('The count is '||bookset.count); --> I can see COUNT =1 (why)
end;
The count is 1
The count is 0
name > Harry Potter
name > Ramayana
The count is 2
PL/SQL procedure successfully completed.
SQL> Or better use bulk collect:
declare
    bookset book_table;
    ln_cnt pls_integer;
begin
    bookset := book_table(book_obj('madhu','kongara','sudhan'));
    dbms_output.put_line('The count is '||bookset.count); --> I can see COUNT =1
    bookset := book_table(); --> Assigning back to NULL.
    dbms_output.put_line('The count is '||bookset.count); --> I can see count as 0
    select book_obj(name,author,abstract)
      bulk collect
      into bookset
      from book;
    for i in 1..bookset.count loop --> Now Looping two times.
      dbms_output.put_line(' name > '||bookset(i).name);
    end loop;
    dbms_output.put_line('The count is '||bookset.count); --> I can see COUNT =1 (why)
end;
The count is 1
The count is 0
name > Harry Potter
name > Ramayana
The count is 2
PL/SQL procedure successfully completed.
SQL> SY.

Xpath Debatching in Orchestration -The part 'part' of message 'Message_In_Copy' contained a null value at the end of the construct block

Hi ,
Facing strange issue in Xpath debatching in Orchestration.
Getting following error in construct shape:
The part 'part' of message 'Message_In_Copy' contained a null value at the end of the construct block
Code inside the construct block:
sXpath = System.String.Format("/*[local-name()='Customers' and namespace-uri()='http://Debatch.Customer']/*[local-name()='Customer' and namespace-uri()='http://Debatch.Customer' and position()={0}]", nLoopCount);
System.Diagnostics.Debug.WriteLine(sXpath);
Message_In_Copy= xpath(Message_In, sXpath);
Schema used:
<?xml version="1.0" encoding="utf-16"?>
<xs:schema xmlns="http://Debatch.Customer" xmlns:b="http://schemas.microsoft.com/BizTalk/2003" targetNamespace="http://Debatch.Customer" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="Customers">
<xs:complexType>
<xs:sequence>
<xs:element minOccurs="0" maxOccurs="unbounded" name="Customer">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="id" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Can anyone help me out ? to identify the root cause for above issue.
Thanks,
Kind Regards,
girsh
girishkumar.a

I agree with Shankycheil here, querying XPath will return XMLNode and thus can't be assigned to XMLNode.
But for debatching in Orchestration using Xpath is not a very good idea.
Because using XPATH loads the complete message in memory(XML Structure) and then performs processing.
This approach is always prone to throwing Out of Memory exception and low in performance also.
Therefore I would suggest you to perform debatching by calling XML Disassembler(XMLReceive) pipeline.
As pipeline works with Stream it will have better performance and you will also get complete control over the messages.
Refer the below samples for debatching using XML Receive pipeline within Orchestration.
Comparrison between XPATH and ReceivePipeline for Debatching:-
De-batching within an orchestration using XPath or calling a pipeline
Debatching within Orchestration using Pipeline-
http://tech-findings.blogspot.in/2013/07/debatchingsplitting-xml-message-in.html
https://jeremyronk.wordpress.com/2011/10/03/how-to-debatch-into-an-orchestration-with-a-pipeline/
Thanks,
Prashant
Please mark this post accordingly if it answers your query or is helpful.

Struts ActionForm bean retuning null values

Hello friends,
I am new to struts framework, I am trying a simple application which gets form details from user store it in ActionForm and showing in a jsp. Now the problem is when i try to get the bean values form the Action form it is returning only null values. but the values i entered in <html:form> is getting stored in the ActionForm.
I am very much confused with this problem.Your help is greatly appreciated
regards,
Muthu

r035198x wrote:
I'm not too sure about this but I think struts questions are not all that welcome in this forum.
Better try the dedicated struts forum at Apache.They're not per definition forbidden here, but it's just merely that you will have more chance to meet real Apache Struts experts at a Apache Struts forum instead of a general Sun Servlet forum, let alone Sun JSP/JSTL or Sun JSF forum.

Anyone else getting JavaScript TypeError - Null value?

Anyone else getting JavaScript TypeError - Null value? I get it on Amazon all the time now. Nothing seems to fix it... What's up with Safari and Java?

Java and Javascript are different. For more on their differences see:
http://members.ozemail.com.au/~phoenix1/html/getstart.htm
That said, Javascript which fails in Safari usually is something that is non-standard since Safari makes a genuine effort to follow http://www.w3.org/ standards. If you encounter a website that doesn't follow these standards, point them to http://www.anybrowser.org/ for guidance on making more uniformly compatible websites. In the meantime there are many other web browsers made for Mac OS X like Firefox, Mozilla, Netscape, Omniweb, Camino, Internet Explorer, Opera, and iCab. If you find a website that doesn't behave well in Safari, use the Report bug to Apple in the Safari menu. There is a Safari Enhancer which has a User Agent submenu in the Debug menu it enables. That same Debug menu can be enabled from Applications -> Utilities -> Terminal via this command line:
defaults write com.apple.Safari IncludeDebugMenu 1
The User Agent specified will spoof certain websites into thinking you are using a different web browser. In the end though, it usually is better to inform webmasters when their website is not accessible.

Automated row fetches, checkboxes and null values

Hi
In Apex3 I have a page with automated fetch row process that is working fine. Now I need to add a new not null varchar2 column "flag" which can be a Y or a N.
To do so, I created a new checkbox item p1_flag, set the source properties and the LOV definition to: STATIC2:Flag set;Y
However when I try to save the data with the checkbox unticked I get a null value error. To solve it, I created a computation on that field like this:
nvl(:p1_flag, 'N')
Is this the best way to do it? (other than using database triggers)
Thanks
Luis

Hi Patrick
Thanks for the reply. I thought that, just wondered if there were a better way...
Another option that I was thinking about was to modify the column definition to be nullable, with valid values being Y and null. So I wouldn't have to care about it. The only thing being that I don't like very much the idea of modifying the database design because of the development tool (though I saw things much worse than this, as using VARCHAR2 instead of DATE because the front end tool didn't handle date datatypes very well!)
Or just stick to a trigger to do it.
Cheers
Luis

Better technique null values

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