Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
?
Solved

NULL value problem (URGENT please!)

Posted on 2003-12-04
6
Medium Priority
?
233 Views
Last Modified: 2010-04-01
From my JSP program I need to execute an SQL insert statement:

***JSP file**
<%
String st1;
...
...//some work done on st1
..

count = stmt.executeUpdate("insert into mytab (f1, f2,..) values ('st1', ...,..)");

Here when I execute above statement, I do not know if string "st1" has some value or if it is null. If "st1" has some value, no problem.But if "st1" has no value, the above statement is entering the string "nu;;" in the above table:
SQL>select f1 from mytab:
f1
==
null

How can I change my JSP to avoid entering "null" when st1 does not have any content?

please help!
0
Comment
Question by:tooki
  • 2
4 Comments
 
LVL 4

Expert Comment

by:vk33
ID: 9880461
What value do you want to be inserted if st1 is null or empty? If you need the null-value (not the 'null' string) you should exclude the f1 parameter from the list:

if (st1 == null)
   count = stmt.executeUpdate("INSERT INTO mytab (f2,...) VALUES (...)");
else
   count = stmt.executeUpdate("INSERT INTO mytab (f1,f2,...) VALUES ('" + st1 + "',...");

And I would suggest using PreparedStatement instead:
PreparedStatement st = conn.prepareStatement("INSERT INTO mytab (f1,f2,...) VALUES (?,?,...)";
st.setString(1,st1);
st.setString(2,...);
count = st.executeUpdate();

Regards!
0
 

Author Comment

by:tooki
ID: 9880724
Thanks!
But is was ok if I was ambigupus about only one field (if it is null) in that satement. but if in the insert sql statement has say 5 fields and I know that any of them can be null, then it becomes difficult.

And when a string is null, I would like to enter no value (In oracle it is NULL) for that field insead of the string "null".

Isn't there any better way of this null check?just wonder..

-tooki
0
 
LVL 4

Accepted Solution

by:
vk33 earned 100 total points
ID: 9880785
yes, sure! Use PreparedStatement, it will solve the problem:

PreparedStatement st = conn.prepareStatement("INSERT INTO mytab (f1,f2,f3) VALUES (?,?,?)";
st.setString(1,st1);
st.setString(2,st2);
st.setString(3,st3);
count = st.executeUpdate();

If any of these strings are null, you'll have a NULL value in the database.

Regards!
0
 
LVL 30

Assisted Solution

by:Mayank S
Mayank S earned 100 total points
ID: 9926311
Or maybet that you can write a utility function like:

public String getValidString ( String sCheck )
{
  return ( sCheck == null ) ? "" : sCheck.trim () ; // if not null, then it also trims it - optional

} // end of getValidString ()

Now you can use this method everywhere in your code, like:

count = stmt.executeUpdate("insert into mytab (f1, f2,..) values ('" + getValidString (st1) + "','" + getValidString (st2) + "',  ...,..)");

Mayank.
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Choosing the right mix of apps is very much necessary for CPAs for making the most of the latest technology through which they can boost their growth.
Welcome to 2018! Exciting things lie ahead in the world of tech. To start things off, we compiled great member articles on how to stay safe, ways to learn, and much more! Read on to start your new year right.
This video shows how to quickly and easily deploy an email signature for all users in Office 365 and prevent it from being added to replies and forwards. (the resulting signature is applied on the server level in Exchange Online) The email signat…
The Relationships Diagram is a good way to get an overall view of what a database is keeping track of. It is also where relationships are defined. A relationship specifies how two tables connect to each other. As you build tables in Microsoft Ac…

577 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question