Re: Null

[PTS]

In several of the fields of the database the information is not entered 
until a later time and thus the field is null. If you look at actual data 
the value is null. When returned the data either is "null" or is not 
compatible with the data needed back. I am using the data in several areas. 
If I am expecting a String and it is null, then I want an empty string to be 
displayed. If I am expecting a number then I want a 0 if it is null. If the 
data returned is not of the type expected then I catch the exception and 
return the equivalent of no information for that data type.

As for the String[], I am pulling back an entire row from the database and 
then picking a single element from the array. In essence it allows me to 
treat the result set as a two dimensional array.

The concept that I was trying to convey to the OP was to do a try catch and 
return the desired default value of the proper type.

Doug

----- Original Message ----- 
From: "domenico di leo" <[EMAIL PROTECTED]>
To: "Tomcat Users List" <users@tomcat.apache.org>
Sent: Wednesday, June 27, 2007 7:08 AM
Subject: Re: Null


If I have understand your problem is : you receive a lot of null value
afther a query but you don't except them.
The problem could be in your if statement .

((String[])queryResults.elementAt(r))[c]).equalsIgnoreCase("null"))

you compare a String vector with a String because you have upacsted to
String[]  the return value of queryResult.
I think you should do something like this:

String[] queryResult = new String[10]
/* Suppose that the queryResult method yelds a vector fill with 10 String

queryResult = new ((String[])queryResults.elementAt(r))[c])

afther

for (int i=0; i<= queryResult.lenght(); i++){
if queryResult[i].equalsIgnoreCase("null"))
   return null; // Why do you use "" ?
 return queryResult[i];
}

Cheers

On 25/06/07, Propes, Barry L <[EMAIL PROTECTED]> wrote:
yeah, this seems like a good solution, too.

-----Original Message-----
From: PTS [mailto:[EMAIL PROTECTED]
Sent: Saturday, June 23, 2007 12:29 PM
To: Tomcat Users List
Subject: Re: Null


I had to deal with a lot of null values coming back from a database. I 
may
have been reinventing the wheel but I wrote a little DBUtil class that I
used to sanitize the returned data. I wrote a get for each type of data 
and
did a try catch. If the data came back not null I simply returned it, if 
it
came back null it threw an exception and I returned back a default value 
in
the catch clause.

For text:

   /** returns the row and column equivalent from the DBResults or empty
string if null or out of bounds*/
  public String getDataP(int r, int c){
   try{
    if 
((((String[])queryResults.elementAt(r))[c]).equalsIgnoreCase("null"))
     return "";
   return(((String[])queryResults.elementAt(r))[c]);
  }catch(Exception e){return "";}
  }

For numbers:

   /** returns the row and column equivalent from the DBResults or string 
0
if null or out of bounds*/
  public String getDataN(int r, int c){
   try{
    if 
((((String[])queryResults.elementAt(r))[c]).equalsIgnoreCase("null"))
     return "0";
   return(((String[])queryResults.elementAt(r))[c]);
  }catch(Exception e){return "0";}
  }


For time:

    /** returns the row and column equivalent from the DBResults or 
string
00:00:00 if null or out of bounds*/
  public String getDataT(int r, int c){
   try{
    if 
((((String[])queryResults.elementAt(r))[c]).equalsIgnoreCase("null"))
     return "00:00:00";
   return(((String[])queryResults.elementAt(r))[c]);
  }catch(Exception e){return "00:00:00";}
  }


Doug

----- Original Message -----
From: "Propes, Barry L " <[EMAIL PROTECTED]>
To: "Tomcat Users List" <users@tomcat.apache.org>
Sent: Friday, June 22, 2007 1:11 PM
Subject: RE: Null


that doesn't sound right....are you sure you're pulling back a value from 
a
column that's a string?

-----Original Message-----
From: Mohammed Zabin [mailto:[EMAIL PROTECTED]
Sent: Thursday, June 21, 2007 6:02 AM
To: Tomcat Users List
Subject: Re: Null


I tried it the other way, if( rs.getString("field") == null ) but the
compiler plames that null can't be compared to string....

On 6/21/07, Tim Funk <[EMAIL PROTECTED]> wrote:
>
>
> if (null == rs.getString("col_foo")) {
>    out.println("<td>&nbsp;</td>");
> } else {
>    // Evil since this doesn't escape the xml - for edutainment only
>    out.println("<td>" + rs.getString("col_foo") + "</td>");
> }
>
> -Tim
>
> Mohammed Zabin wrote:
> > Hi All
> >
> > Anyone knows how to deal with null values in JDBC ResultSet??
> >
> > I am trying to render a table in jsp page that read its value from 
> > the
> > database, sometimes, the database returns null values, and so, the 
> > whole
> > table couldn't be rendered. Is there any way to deal with null 
> > values.
> >
> > Thanks
> >
>
>
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