• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

Database help

 
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Guys I don't do this much but I'm in a desperate situation I have to have an assignment in, in 2 hours,and I'm quite stuck on a problem I have never asked for help on assignments before it's just not my thing but right now I'm in a predicament that's the only reason why I'm posting such a large chunk of code,

anyway with my rambling out of the day I'm trying to insert details name and authors name into my database library in the table books I can connect perfect nothing wrong with the connection but when I press the add button I get an exception

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Gui$2.textActionPerformed(Main.java:79)
at SideBar$1.actionPerformed(SideBar.java:46)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)




here is my code





sidebar.java





sorry about the length it's probably an absolute headache to read any help would be greatly appreciated

thanks
 
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Shouldn't this
be
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Carey thanks for the reply

I changed it to that but still get an exception =( nullpointer exception

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Gui$2.textActionPerformed(Main.java:80)
at SideBar$1.actionPerformed(SideBar.java:46)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I think the problem is with this block of code but I'm not sure why it's given me an nullPointer exception

 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I changed the code a little bit and got rid of the nullPointer exception but I'm still getting an exception java.sql.exception

didn't add
java.sql.SQLException: Can not issue data manipulation statements with executeQuery().
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
at com.mysql.jdbc.StatementImpl.checkForDml(StatementImpl.java:463)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1326)
at Gui$2.textActionPerformed(Main.java:80)
at SideBar$1.actionPerformed(SideBar.java:46)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
 
Carey Brown
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Your variable insertStmt has not been set to anything.
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Carey thanks for the reply =)

I changed the code and it doesn't give me a nullpointer exception anymore but I still get an sql exception,not sure why

 
Carey Brown
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
 
Carey Brown
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Strings need to be surrounded with quotes in SQL. So...
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Carey thanks for the reply much appreciated I'm still getting an sql exception for some reason

java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)


I'm guessing it's in the same block



thanks
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator


sorry that's from another button which I'll solve later

the sql error message I am getting is

didn't add
java.sql.SQLException: Can not issue data manipulation statements with executeQuery().
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
at com.mysql.jdbc.StatementImpl.checkForDml(StatementImpl.java:463)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1326)
at Gui$2.textActionPerformed(Main.java:81)
at SideBar$1.actionPerformed(SideBar.java:46)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Guys I fixed the problem but I still have an issue which is a huge issue

the first entry will work but when I try to enter the second one it will say duplicate entry how do I get my Id to increment I tried Id++ but that didn't seem to work,there can't be only duplicate entries because ID is the primary key

 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Ok guys I figured out that problem I created a global variable Id because every time I entered the function Id would be set to 8 giving duplicates,

but now a I touched on before when I try to print the list of books or authors I still get an exception after I printed out the list once from the database

java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)

 
Sheriff
Posts: 7125
184
Eclipse IDE Postgres Database VI Editor Chrome Java Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
What if ID were a static class member?

There are better ways of doing this, but not in 5 minutes.
 
Carey Brown
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
In the code you just posted you initialize Id to 8 and then increment it, so, Id will always be 9.

Make Id a class level variable and initialize to zero, then increment it each time you call update.

You are not closing your result sets or statements anywhere.

Methods should begin with a lower case letter, i.e. gui().
 
Rancher
Posts: 4801
50
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Each query (Statement and ResultSet) should be isolated from the rest of the code.
At the moment you are sharing statement objects (by the look of it) and result sets.
When a Statement is reused any prior ResultSets are closed automatically.

So, the structure should normally be (assuming a fixed connection):

And similar ones for saving changes (though they won't return a List obviously).

In your current issue your stack trace should show you exactly which result set is causing the problem.
 
Marshal
Posts: 79153
377
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Adam Chalkley wrote:. . . a global variable . . .

Global variables are usually a very bad idea in an object language.

java.sql.SQLException: Operation not allowed after ResultSet closed  . . .

Sorry I'm late to the party, but how did you test the database code before you created the GUI?
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thanks guys for all the input

and no not really Campbell
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
hi guys I changed my code around a little bit to create multiple result sets and yes I know it's very sloppy but I'm just trying to get this accomplished before I tidy it up and optimise it anyway here is now my main method




I'm getting a null pointer exception

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Gui.printBooks(Main.java:103)
at ToolBar.actionPerformed(ToolBar.java:53)


this is the line of code it's complaining about

 
Carey Brown
Saloon Keeper
Posts: 10687
85
Eclipse IDE Firefox Browser MySQL Database VI Editor Java Windows ChatGPT
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

You should create the statement and the ResultSet as local variables to the mehtod. There's no sense in keeping it around in your resultSetArray. That's only asking for trouble. And be sure to close() the statement when your done with it.
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thanks Carey great advice that worked =)
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
hi guys I've run into another problem,the problem is I created an ArrayList to store all the names of the authors,I call a helper method called exists to check if the name is already in the list if it is it doesn't add it to the list so the name shouldn't get printed the problem is that each author seems to get printed exactly four times when I run the code

TestAuthor1
TestAuthor1
JK Rowling
TestAuthor1
JK Rowling
J.R.R Tolkien
TestAuthor1
JK Rowling
J.R.R Tolkien
Suzanne Collins

here is the block of code in question




also the helper method

public int exists(String name){

for(String a: authorNames){

  if(a.equals(name)){
 
  return 1;
  }
}
return -1;

}
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
 
Saloon Keeper
Posts: 15491
363
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
You should let the DBMS handle the filtering. Write a query that gets the distinct authors in the database:
Anyway, even if you insist on doing this in your own code, why does exists return an int? You should use appropriate data types. For a yes/no question, the appropriate data type is boolean.
 
Dave Tolls
Rancher
Posts: 4801
50
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
As Stephan says, let the DB do what it does best, and that is searching/filtering stuff.

Also, try and avoid bringing stuff back from the database that you don't actually need.
If you are querying for the author name then only bring back the author name, not the entire row.  It will make the query clearer, and involve less data travelling around the place.
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thanks Stephan,and true yeah boolean would have been a more logical choice,

any idea why it actually prints the authors four times?

thanks
 
Dave Tolls
Rancher
Posts: 4801
50
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Each time around the while loop for the result set you are printing the entire contents of the authorname List.
Presumably you only actually want to print the List after you've finished processing the result set.

By the way, if the authorNames collection is supposed to only hold unique names then why not make it a Set?
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thanks guys much appreciated that also saved me a lot of code,

true I was considering a set or even a hashMap but that would require more implementation
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
projects almost done just in the testing phase

one of the tests I'm doing is to see if my code is vulnerable to mySQL injection anyway it doesn't seem like it is because none of the code is being executed on the server

but I didn't sanitise my code in any way so I'm not sure why the sql injection isn't working not that it's a bad thing but i would expect it to work

for the user name I typed randomName and for author I typed in randomauthor'OR DELETE FROM `books` WHERE `books`.`ID` = 12;#

I also tried

randomauthor'AND DELETE FROM `books` WHERE `books`.`ID` = 12;#

and

randomauthor'DELETE FROM `books` WHERE `books`.`ID` = '12';#

none of which worked the data above didn't even get added to the database instead the output just stayed blank,

any idea how I can test to see if my application is vulnerable? or why the sql query isn't getting executed?

ps if anybody wants to try themselfs I can copy and paste all the source code here with the database info they will need to crate a simple database

thanks
 
Stephan van Hulst
Saloon Keeper
Posts: 15491
363
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Show us the code that processes the user input, from event handler to database access.
 
Knute Snortum
Sheriff
Posts: 7125
184
Eclipse IDE Postgres Database VI Editor Chrome Java Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Did you forget a URL to your source?  Or are you saying all the source code is here in this topic?
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
@Stephan



@Knute I can include all the code here if you want to try it
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thanks
 
Knute Snortum
Sheriff
Posts: 7125
184
Eclipse IDE Postgres Database VI Editor Chrome Java Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Why aren't you using a PreparedStatement instance?  Then you wouldn't have to worry about injection attacks.
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
@Knute very true but first I want to test if my code is vulnerable to sql injections to document  the outcomes then make the changes to my code such as prepared statements

thanks
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
When I type

HI'OR '1' = '1'

I get this error,so obviously the mysql code is getting executed but I'm typing something wrong in the syntax?

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'HI')' at line 1
 
Stephan van Hulst
Saloon Keeper
Posts: 15491
363
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Well, there's not much we can do with that, because you have two injection points: author and name. What did you enter for both?
 
Knute Snortum
Sheriff
Posts: 7125
184
Eclipse IDE Postgres Database VI Editor Chrome Java Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
What about adding some debugging?
 
Adam Chalkley
Ranch Hand
Posts: 545
4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
hi guys

I entered Hi for name

and HI'OR '1' = '1' for author
 
Always! Wait. Never. Shut up. Look at this tiny ad.
a bit of art, as a gift, the permaculture playing cards
https://gardener-gift.com
reply
    Bookmark Topic Watch Topic
  • New Topic