Almost all APEX applications I’ve been working with recently are used across multiple timezones, where many timezones uses DST (Daylight Saving Time) – that is basically almost all Europe and North America. The natural requirement is that users can see date+time information in their timezone time, reflecting if DST is active or not. Timezones and time conversions are always bit of mess and APEX is not supporting this completely out of box, but with small effort we can make our applications really global. Continue reading Timezones and DST in Oracle APEX
Normally Xen is deployed with plenty of of public IPs, so it can use bridged networking and each virtual machine can have it’s own public IP. However in my case I was limited by only 1 public IP, but I wanted to run several VMs with services accessible from outside. Solution was to modify XEN networking scripts.
Idea is to use an internal bridge with hidden IP subnet and to use NAT and port forwading so particular services on VMs can be reached from outside (on public IP, which is assigned to DOM0).This solution works for me successfully on Debian Squeeze. Continue reading Xen 4 – Combined Bridged And NAT Networking
However there are some functionalities, that are not available in SDK and then more effort is needed and XPCOM components have to be used via their JS interfaces. This requires bit more research, so I’d like to share one useful snippet of code – how to save string to file, which user has chosen via standard file picker dialogue: Continue reading Writing to file in Firefox Extension
I have an Oracle 11g installation running in virtual machine (under Xen). Oracle is used for APEX development and some host few local applications for our team. From time to time I need to do cold backups – to keep data around or to move them to another VM on different server, which is running identical version of oracle and can be used as cold backup eventually. The backup device is an USB disk with FAT32 filesystem (FAT32 was chosen a while ago for compatibility reason – to be able to attach it to almost any OS) and the disk is attached to other server. FAT32 means that there is a limit on file size, so the database backup need to be split to chunks (backup is 10-15 GB). Of course RMAN can do proper job, but since I’m no real DBA I want to have something quick ( data are not mission critical and also it is no problem to bring DB down) – so warning do not apply this procedure for important databases – no guarantee that it will work in all circumstances and you may loose your data . Continue reading Quick And Dirty Oracle Backup
GSetttings is the standard way how Gnome 3 applications store their configuration. GSettings is the front-end interface for application, actual values are stored by back-end – standard one is called dconf. We can then use the tool dconf-editor to easily browse all stored configurations for all applications. Thanks to GObject introspection we can also work easily with GSettings from python. Continue reading GSettings – Flexible Configuration System
TheTool v.02 is available – this small handy tools now enables networks detection and setting proxy according to which network computer (e.g. notebook) is just connected. Plus has now very flexible system for defining other actions. More on it’s own page.
APEX 4.1 enables to include a download link to LOB object in standard or interactive repors. Documentation is available here, however the approach is not so obvious from it. So here is quick recap, how it works:
- In report query you must have column that contains LOB length (not LOB itself!) – so something like
select dbms_lob.getlength(MY_LOB) my_lob_lenght from MY_TABLE
- The report column corresponding to LOB length should be set as:
Display As: Display As Text (escape special characters, does not save state)
Number/Date Format: DOWNLOAD:TABLE_NAME:LOB_COLUMN_NAME:ROW_PRIMARY_KEY_COLUMN
(beware names are case sensitive here)
- When more sophisticated download behaviour is needed you should also include columns for MIME type of data, file name and modification timestamp. Once you store basic DOWNLOAD format you can edit it with masked edit link “BLOB Download Format Mask”
- Download link is only shown when LOB length > 0 and is not null.
Recently I needed to record some screen-cast from Linux desktop. In past I was using gtk-recordmydesktop, which basically worked well, but I thought maybe there is something better. And I have found this combination of two tools very useful – Kazam (screencaster) and OpenShot (video editing) . Kazam is easy to use with all basic functions that are needed (screen area definition, multi-display support, audio source selection) and it supports output into two common formats (MP4, WebM). When screen-cast is finished Kazam gives you opportunity to open it directly with a video editor – here OpenShot can be used to cut your screen-cast video, add titles etc. and finalize screen-cast video. Continue reading Nice Solution for Recording Screencasts on Linux
Debian/Ubuntu do not have bash autocompletion enabled for root account by default. When working under root account, this is quite missed feature, but luckily it can be enabled very easily:
apt-get install bash-completion # if not installed - like in minimal Debian install
add folowing to the file:
if [ -f /etc/bash_completion ]; then