Matching a String with a certain record

[chris le]

Hey guys, I'm a ColdFusion developer and have just started into java.
In ColdFusion if you want to see if a string matched the name of a column value (from a database) you would do this:

 
<cfquery name="getData" datasource="myDS">
select title
from reports
</cfquery>
 
<cfif title eq "Creepy Mongoose">
 
  ....blah blah
 
</cfif>
 

How would I check for a value like this in Java?
Here's what I got:

  
while(myResultSet.next()){
  id = myResultSet.getInt("id");
  firstname = myResultSet.getString("firstname");
  lastname = myResultSet.getString("lastname"); 
  
  if (firstname == "Chris"){
    System.out.println("Chris is cool!");
  }
}//end while loop
 

Any ideas?
Thanks guys and take care,

Chris

[fred rosenberger]

common question. simple answer:

don't use "==", it's checking for something else entirely than what you think it is.

use the ".equals()" method...

if (firstname.equals("Chris"){
   ///
}

if you search around on this site, you're bound to find a more tech. answer. or, wait a while and somebody will post it here (i may myself later when i have more time...)

good luck!!!

[chris le]

Thanks for the help!
But here's another question along the same lines.
Why does it have to be in a loop to work.

I have tried this:

 
 
while(myResultSet.next()){
  id = myResultSet.getInt("id");
  firstname = myResultSet.getString("firstname");
  lastname = myResultSet.getString("lastname"); 
  System.out.println(this);
}//end while loop
 
//this pulls the last record from the while loop "John" why?
if (firstname.equals("Chris")){
  System.out.println("Chris is cool");
}
 

 
//I tried this as well
rd.myResultSet.first();
if (firstname.equals("Chris")){
  System.out.println("Chris is cool");
}
 

It doesn't match it because the cursor is still on the last record "John".
Why is this happening even after I user the first() method? I even tried the absolute method.

Any ideas?
Thanks!

[Julian Kennedy]

Hi Chris,

The JDBC code you're using is at a lower level than ColdFusion tags. It gives you a lot more control over how you interact with the database. Consequently it requires more code to do the simple things. ColdFusion is akin to the tags provided by JSTL or Struts. These technologies do the simpler things very succinctly, further hiding the complexity behind the scenes from the developer. In simple terms a loop is required as your ResultSet returns more than one row.

Your second question is more difficult. Your JDBC driver has given you a ResultSet of ResultSet.TYPE_FORWARD_ONLY, which suggests only JDBC 1.0 support. JDBC 2.0 introduced scrollable ResultSets which support the first() and last() methods, etc. Calling rs.first() on a forward-only ResultSet has no effect, hence the ResultSet still points at the last record found by rs.next().

Hope that helps. As you appear to crave a full understanding of these concepts I suggest you have a good browse through the API documentation for the java.sql package on Sun's website and also study the JDBC 2.0 tutorial there.

Jules

[Dirk Schreckmann]

Note that the API documentation Julian mentioned is available at
http://java.sun.com/j2se/1.4.2/docs/api/

Sun's JDBC tutorial is available at
http://java.sun.com/docs/books/tutorial/jdbc/index.html

Moving this to the JDBC forum...

[Peter den Haan]

It's not exactly best practice, but you might get a lot of mileage out of exploring the SQL tags in the JSTL (JSP Standard Tag Library).

- Peter

[chris le]

Hey, thanks a lot guys. I'll take a look at those suggestions.

Take care,

Chris

[Julian Kennedy]

Chris,

If you want a ResultSet that isn't just FORWARD_ONLY, try the version of Connection.prepareStatement that takes the SQL string plus two int parameters for ResultSet type and concurrency. You'll need a JDBC 2.0 dirver for this to work.

Jules