More on CSS selector performance in Oracle APEX

Last month I wrote a post about CSS performance, including some performance test results.

I recently encountered this brilliant post on Medium that describes some best practices for CSS.

While APEX does a lot of this for you, I think it's worth a read by all developers. Even applying basic naming conventions can make code easier to read and understand.

There was also a section on performance that described an issue that my previous (more...)

Last week in Stream Processing & Analytics 5/16/2016

This is the 14th installment of my blog series around Stream Processing and Analytics.

If you have not been able to attend the Kafka Summit in San Francisco last week, then you might like the tweet from Confluent Inc.

I listed most of the presentations below in the section “New Presentations” but I (more...)

Unique constraint WWV_FLOW_WORKSHEET_RPTS_UK violated

If your Apex application import log shows something like this:

...PAGE 73: Transaction Lines Report
ERROR at line 1:
ORA-00001: unique constraint (APEX_040200.WWV_FLOW_WORKSHEET_RPTS_UK)
ORA-06512: at "APEX_040200.WWV_FLOW_API", line 16271
ORA-06512: at line 6

(this is on an Apex 4.2.4 instance)

This is due to a Saved Report on an Interactive Report that was included in the export, which conflicts with a different Saved Report in the target instance. The (more...)

#DBADev (Ops), who knows what is going on…

I have been considering writing this article for quite some time now.
APEX Connect 2016 in Germany’s capital Berlin and the DOAG Database days have finally persuaded me to talk more about #DBADev, let me explain why…

Whenever in the stone age…

During my career as DBA, I was always working closely together with Oracle Forms & Reports developers. In retrospect, the cooperation in that time was remarkable.
These Forms & Reports developers had always (more...)

Difference between SQL Injection and Cross Site Scripting

I came across a tweet from a non-Oracle person I follow that should amuse many web developers:
One of the replies referred to "little bobby tables", eluding to a classic xkcd comic about SQL injection.

Of course I had to make the correction that this was in fact Cross Site Scripting (XSS), not SQL injection. This post summarises syntactical considerations (more...)

APEX Survey Results: Which versions have you experienced?

Following up from the results on when you started learning APEX, here is question 2 from my 2015 survey.

Note that questions such as this offered the respondent to choose multiple selections, hence a count much higher than 192.

Q2: Which versions have you experienced?

I think it's fair to say that most of the 2.x respondents might also be part of the third that said they started prior to 2007.

I started in (more...)

APEX Page Numbering

Today while perusing posts in the #orclapex hashtag, I came across this from Christina Moore.
She hasn't been blogging long but I love her style and format. I found this one on classic report templates a great resource, though I wish the Oracle team would produce content like this to accompany the documentation, or as an extension to  (more...)

Last week in Stream Processing & Analytics 5/2/2016

This is the 12th installment of my blog series around Stream Processing and Analytics.

The most important event last week was probably the first Kafka Summit being held in San Francisco. At the summit, Confluent shared results from a recent survey that clearly shows the rise of Kafka across the enterprise and the growth of stream processing:

  • According to the results, Apache Kafka is most commonly used for stream processing (72% of respondents). In addition, (more...)

APEX Survey Results: When did you start learning APEX?

Early last year I put the call out to #orclapex developers, asking them to fill out some questions in survey (using a packaged APEX application, of course).

The results helped contribute to a presentation I did Kscope15. Thank you to all those who responded. I thought I'd finally post some results, see if it can elicit further discussion, even of a casual nature.

Some of you asked me if I could post these results, so (more...)

Slides and demo script from my ORDS talk at APEX Connect 2016 in Berlin

Hi everybody,

I just came back from the DOAG APEX Connect 2016 conference in Berlin ... very nice location, great content and the wonderful APEX community to hang out with ... always a pleasure. This time we felt a little bit pink ;)

As promised, you can download the slides and the demo script (as is) from my site.

Instructions are included.

See you at KScope in Chicago, #letswreckthistogether .

Cheers and enyoy!

On CSS/jQuery Selector Performance

My post describing the use of a simple selector identifying page spinners was originally going to be about performance, then I learned something I found very interesting.

I likened what I learned to Tom Kyte's essay (Asktom->Resources->Presentations->FalseKnowledge.htm) on Correlation vs Causation. The essence was that things change over time, and we can't always trust authorities on the topic, and we must always test in our own environments. This aligns with skepticism in general, and (more...)

Last week in Stream Processing & Analytics 4/25/2016

This is the 11th installment of my blog series around Stream Processing and Analytics.

First two interesting tweets I found last week. The first one by Steve Wilkes brings it straight to the point:

The second one by Neha Narkhede reveals some impressive metrics about the usage of Kafka @ LinkedIn. 1. (more...)

Improving PL/SQL performance in APEX

One of the simplest tuning techniques to encapsulate PL/SQL used in APEX within packages, minimising the size of anonymous blocks. This applies to any PL/SQL within the page, including computations, processes, plugins, dynamic actions, validations, shortcuts and dynamic PL/SQL regions.

This change can make a big impact in the execution time of PL/SQL as it's processed at compile time instead of interpreted at runtime.

Plug-ins can be wonderful black boxes and consumers may not care (more...)

Email made Easier

an e-mail letter that has a @ sign on itSending emails from the Oracle database can be both simply deceptively braindead easy, and confoundingly perplexingly awful at the same time. Easy, because all you have to do is call one of the supplied mail packages to send an email:

  (sender     => ''
  ,recipients => ''
  ,subject    => 'Test Subject'
  ,message    => 'Test Message');
  (p_from => ''
  ,p_to   => ''
  ,p_subj => 'Test Subject'
  ,p_body => 'Test Message'

If (more...)

Training: jQuery and Dynamic Actions in APEX

Sage Computing Services are happy to announce a new 2 day course for Oracle APEX developers.

jQuery and Dynamic Actions in APEX

This course is designed for APEX developers who know their way around the APEX builder but want to build more interactive & user friendly applications that are also suitable for touch devices.

Upon completion attendees will have a great understanding of the communication between the browser and the database, using dynamic actions effectively (more...)

Declarative Tabular Form dynamic totals

A common Apex project is to take a customer’s existing spreadsheet-based solution and convert it more-or-less as is into Apex. I’ve got one going at the moment, a budgeting solution where users need to enter their budget requests. They currently enter their requests into an XLS template file which generates subtotals and totals for them.

To do this in Apex I’m going to use a tabular form, and to do the subtotals I’ll use jQuery (more...)

Analytics in APEX Charts – Moving Average

Consider a chart with a trend that might be quite jagged across data points (blue line).

What if you would like a smoother version of that line - a moving average, if you will (red line). This stabilises the results, like looking at climate vs weather.
Oracle APEX Line Chart - 2 series
It's fairly easy from a SQL point of view - in this case it's another column in the original chart query

About CSS Selectors

Recently I saw a simple, accepted answer in the forums that tempted me to provide a small extension to the provided answer. This has since spawned two blog post ideas, here is the first.


The following question asked how to hide the spinner from a particular page full of small reports refreshed on a timer.
The answer was some basic CSS, which could be placed in a variety of locations depending (more...)

BIG checkboxes

Getting older, it’s getting harder to see and click those tiny checkboxes…



input[type=checkbox] {
/* Double-sized Checkboxes */
-ms-transform: scale(2); /* IE */
-moz-transform: scale(2); /* FF */
-webkit-transform: scale(2); /* Safari and Chrome */
-o-transform: scale(2); /* Opera */


CAN YOU SEE THEM NOW? Ah, good. That’s all right then.

Brought to you by dept-of-coding-by-copy-and-paste.

Filed under: APEX Tagged: APEX, CSS, tips-&-tricks

Username & password required at Weblogic domain startup

When installing a new WebLogic Domain for any a-specific Oracle (Fusion) Middleware application or any other implementation requiring a WebLogic domain like ORDS for instance, a new ‘home’ is created under [MW-home]/user_domains/. [MW-Home] translates, for instance, to /u01/oracle/product/Middleware.

ordsTo start your brand-new domain, or perhaps and rather, to automate the startup of your domain, you would use the supplied [MW-home]/user_domains/[DomainName]/ command-file.
This file will start the Weblogic domain (the Admin Server) and the deployed (more...)