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XFILES APEX Community Edition (XACE)

Roel Hartman and me are currently very busy with our Kaleidoscope 2011 presentation “XFiles, the APEX Version: The Truth is in There…“. During this presentation, we will demonstrate the awesome possibilities you can create when you combine the APEX and XMLDB functionality of the APEX database environment. And as you probably also know, two “no cost options” delivered with your Oracle database. Our first presentation/demo will be on the AMIS Kaleidoscope Preview Sessions on the 14th of June, to test our “setup” and combined presentation for the real thing during Kaleidoscope, in Long Beach, USA, this year.


The demo will demonstrate how to setup database build-in versioning capabilities, based on standard XMLDB functionality, that can be used by or for APEX applications, while making use of the file/folder metaphor of the XDB Repository.

XFILES APEX Community EditionClick picture to enlarge

The XDB Repository can, by default, be used to, currently via WebDAV or FTP, drag and drop files into the database. This XMLDB functionality also has default versioning, checkin/out, an repository event mechanism and security functionality / capabilities. So why work, while working with this great development environment called APEX, with version tooling like Subversion, if the XMLDB realm of the database already has these capabilities to provide this by default.

The XFILES demo application is used to demonstrate XMLDB functionality but currently still main AJAX based regarding its GUI. In 2008 an effort was made, for that years Oracle Open World conference, by Carl Backstrom (Oracle APEX) and Mark Drake (Oracle XMLDB) to combine the two environments and switch the XFILES AJAX based GUI for the APEX front-end. Due to circumstances, it didn’t had the proper follow up regarding cleaning up the code and share the ideas…see the XFILES tab on this page for more info on this.

Roel and my efforts, regarding this XFILES APEX version, which is based on current and the work done by Mark en Carl in 2008, is called by us, the XFILES APEX Community Edition (abbreviated to XACE), so we are able to implement some chance management without be mistaken by Mark Drake’s still existing AJAX based XFILES version, currently version 5. This version implements and demonstrates Native Database Web Services via XMLDB in the OTN Development Days Virtualbox environment which can be downloaded via Oracle OTN.

More info needed?

More regarding the XFILES XMLDB application and blog posts can be found via the XFILES menu on this site. Information about Roel and his interests can be found on his personal blog and information about official XFILES Oracle XMLDB application and technology can be found on and via the Oracle XMLDB main page. Last but not least, for interest in Oracle APEX go to the site.


To give you a preview of the work done, hereby some updated pictures

XACE - Home PageClick picture to enlarge
XACE - Browser MenuClick picture to enlarge

HOWTO: Reset the admin password for the stand-alone APEX Listener

Sometimes the answer can be so simple…

I wanted to reset the OTN Developer Days Virtualbox APEX Listener admin password without redeploying the apex.war file and destroying the current setup, so I searched all config and properties APEX Listener files I could find. Searched via Google. No useful hits. I found a credential file with the passwords in them on the virtualbox environment, probably MD5 hashed ones, but no clue about how to reset them. At final I got in direct contact with Kris Rice which had put so much effort in setting up this training environment…and was a bit startled about the simple solution…

There’s a file named credentials under ~/.apex/[port numner]/. If you remove that, it will reprompt for the passwords. Let me know if you need anything else.


Life can be so simple.

Updated XML Content & Paper section

Once per year I try to update the “XML Content” page that, in principle, should contain all my XML relevant thoughts and “how to” posts, so I can find my gained “wisdom” a bit more quickly (getting old and stuff). This year I had only 14 and a bit of such XML related posts, which was afterwards easily explained when I updated my “Paper” page where among others I have a list on “presentations” done… Oops… I have been busy…

Anyway. Enjoy the updated XML content overview reference page, it contains now 100+ posts regarding specific XML(DB) related howto’s, solutions, approaches, ideas, etc.


Oracle Database 11g XE Beta — Amazon EC2 Image

That’s right folks! Playing with latest beta of free Oracle Database 11g Express Edition couldn’t be any easier than that. If you are using Amazon EC2, you can have a fully working image with 64 bit Oracle Linux and Oracle 11g XE database running in a matter of few clicks and a minute to get the instance to boot.

Image — ami-ae37c8c7
Name — pythian-oel-5.6-64bit-Oracle11gXE-beta-v4
Source — 040959880140/pythian-oel-5.6-64bit-Oracle11gXE-beta-v4

You can find it in public images and at this point it’s only in US East region.

If you never used Amazon EC2 before, see detailed step-by-step guide on how to get started with EC2 on the example of this 11g XE image.

This image works great with Amazon EC2 Micro instance and I configured it specifically for Micro instance. Micro instance costs you only 2 cents per hour to run or even less than 1 cent if you are using spot instance requests (and there is free offer for new AWS users as Niall mentioned in the comments).

So what’s there?

  • Oracle Enterprise Linux 5.6 64 bit (I started with 5.5 and updated to the latest)
  • Oracle Database 11g XE Beta (oracle-xe-11.2.0-0.5.x86_64)
  • Database created and configured to start on boot
  • APEX coming with 11g XE configured on port 8080 and remote access enabled
  • 10GB root volume on EBS with 5+GB free for user data. You could store up to 11GB of data in 11g XE and there is a way to grow volumes if you need but for more critical use then playground, I’d allocate separate EBS volumes anyway.

Few things worth to mention:

  • I enabled public key authentication (“PubkeyAuthentication yes” in /etc/ssh/sshd_config) so you can setup shared key to login directly as oracle OS user – just copy your public key to /home/oracle/.ssh/authorized_keys.
  • SYS and SYSTEM password is “pythian”. Change it!
  • ADMIN password in APEX is “pythian” — change it on the first login.
  • Micro instance has 613 MB of RAM and no swap — no instance (ephemeral) storage.
  • Oracle database and listener autostarts on boot. You can use /etc/init.d/oracle-xe stop/start as root too.
  • listener.ora has been modified to include (HOST=) so that it starts on any hosname/IP.
  • Ports 1521 and 8080 are open to the world on local iptables firewall. You still need to configure proper Security Group to be able to access those ports.
  • Access APEX on http://{public-ec2-ip}:8080/apex and admin on http://{public-ec2-ip}:8080/apex/apex_admin. There is currently an issue that APEX stops working after few minutes of run-time returning 404 code. Might be a bug in beta or installation issue (for example, I run it with no swap on Micro instance).

I will be keeping the AMI up to date as things develop so AMI id could change — check back here of just search public AMIs for the latest image. I setup short URL for this page —

If you don’t know how to use Amazon EC2 – I recommend to read the second chapter of Expert Oracle Practices: Oracle Database Administration from the Oak Table. This chapter was written by Jeremiah Wilton who’s been long time playing with Amazon EC2 for Oracle before any of us even thought of it.

When few folks confirm that it works, I’ll submit an image vi

Update 4-Apr-2011: Create v3 image – fixed typo in database passwords, fixed retrieval of public key for ssh login as root, changed startup sequence so that ssh keys are initialized earlier as well public key retrieval.
Update 4-May-2011: Created v4 image – Increased SGA size to 212M. Set large_pool to 32M (Automatic SGA management doesn’t do it’s job properly – this is why APEX was not working – not enough large pool memory allocated). Enabled DIRECT IO and ASYNC IO for filesystem – buffered IO slowed down things a lot. Now APEX is actually pretty usable on Micro instance. Remember that you can run it on large instance to run in comfort but you are overpaying since there is 2 CPUs in large instance and 7.5GB of RAM while you can’t use more than 1GB. Of course, you could disable Direct IO and use OS buffering to take advantage of more RAM but can’t leverage both cores with APEX (it limits capacity to a single core).
Update 23-Jul-2011: If you need to use networking services from APEX (like web-service, sending emails and etc) then you need to configure network ACLs for APEX_040000 user.

Review: Oracle Application Express 4.0 Cookbook

I decided to add a twist to my usual blogs - a book review, which I have not done before. I have been reading a book - Oracle Apex 4.0 Cookbook by Marcel van der Plas and Michel van Zoest and published by Packt, a UK based publisher. Michel is one of the first Apex Certified Experts in the world - a no small feat. It has been technically reviewed by a well known cast - Oracle ACE Director Dimitri Gielis, who also won Oracle Magazine's Apex Developer of the Year in '09; Maarten van Luijtelaar and Oracle ACE and frequent blogger Surachart Opun.

HOWTO: Mount your Database as File System via WebDAV under Linux

No, no this isn’t another DBFS post but a more simple and direct way of achieving the same


Just had a funny discussion with Roel Hartman regarding how to trick the Tomcat APEX 4 setup in believing that the virtual XFILES directory in the database was actually available on disk of the local server. This is probably not the way to solve this but should be realized via Tomcat / APEX 4. The OTN Development virtualbox environment with APEX 4 gets his “/i/” images via Tomcat from the directory.

#66cc66;">[oracle@localhost i#66cc66;">]$ pwd

The easiest solution would have been to copy the XFILES images and files in a directory called XFILES under the ROOT directory.