Interval-Reference Partitionierung in 12c

Früher einmal habe ich meine Blog-Beiträge selbst erdacht und geschrieben - inzwischen gebe ich sie gerne in Auftrag oder lasse sie in Auftrag geben. So auch hier: in der letzten Woche war Markus Flechtner von Trivadis bei uns im Haus und hat uns in die dunklen Geheimnisse von Oracle 12 eingeweiht. Viele Fragen blieben nicht offen, aber einer meiner Kollegen hatte ein paar Detailfragen zum Thema Interval-Reference-Partitionierung und row movement. Ich hätte es wahrscheinlich bei (more...)

2016 Blog Review

It's February, so it must be time to do this. I explore what thoughts arise from looking back, and forward to the future. It helps me to remember stuff, decide what to do, and apparently some people find it interesting.


So many tools. And I arguably don't use enough of them.

APEX 5.1

It's out and I'm excited. Unfortunately, scheduling is super tight, so I'll be waiting at my current site until hopefully around (more...)

Oracle Developer Cloud for NodeJS application Testing Automation using Jasmine

This blog will help you understand usage of Oracle Developer Cloud service for automated testing of NodeJS REST based web service application using a popular testing framework called Jasmine. The NodeJS application will be deployed on Oracle Application Container Cloud Service.


Note: For details on how to develop and deploy NodeJS REST application on Application Container Cloud using Developer Cloud service, please refer the blog link mentioned below.




How did you get into programming in the first place?

If you want a sanity check on programming life, I recommend you follow @ThePracticalDev in some form.

Recently a question was posed regarding we all got into programming in the first place.
There are a few interesting posts, here is my submission.

The Vic-20 was the first introduction, using BASIC pokes recorded on tape, but I think it was seeing the use of a variable in a simple Pascal programme over the shoulder (more...)

APEX Survey Results: Addressing Performance

Yep, I'm still doing this. A bunch of questions to come, many worth the visit. Just a few weeks between drinks, so to speak. My annual review is a little late, too. Anyway...

Time for the performance questions in my 2015 survey. A favourite topic of mine, and my boss, Penny Cookson, lives for tuning.

Q9. How do you proactively address performance? (tick all that apply)

Tune SQL - I would be surprised if this (more...)

Quick Pick in Apex Report

I have an Interactive Report that includes some editable columns, and the users wanted to include some “quick picks” on these columns to make it easy to copy data from a previous period. The user can choose to type in a new value, or click the “quick pick” to quickly data-enter the suggested value.


Normally, a simple page item can have a quick pick by setting the Show Quick Picks attribute on the item. This (more...)

Truncating LISTAGG prior to 12.2

I've been following the LISTAGG problem for a while because I find the function useful.

The problem being this error:
ORA-01489: result of string concatenation is too long

It relates to when the result set is over 4000 characters, eg:
with data as (select rpad('x',400, 'x') str from dual connect by level <=10)
select listagg(str,', ') within group (order by null)
from data
Ten rows of 400 characters equals 4000, add the concatenation operator and you get (more...)

Nicht deterministische JDBC-Anmeldeprobleme mit Oracle

Im Lauf der Woche bin ich einem Problem beim Zugriff auf eine Oracle-Datenbank via JDBC begegnet, das eine umfangreichere Schilderung verdient hätte - wenn Uwe Küchler diese Schilderung nicht schon vor einigen Jahren in seinem Blog unter Berücksichtigung aller relevanten Details durchgeführt hätte. Das Problem lag darin, dass Anmeldungen in manchen Fällen problemlos erfolgten, dann aber wieder in Timeouts liefen, ohne dass sich dafür auf Netzwerkebene eine Erklärung finden ließ. Verantwortlich ist die Verwendung von (more...)

RI (Referential Integrity) Constraints: 3 Reasons to Include Them in Your Data Warehouse

3 Reasons to Include Referential Integrity Constraints in Your Data Warehouse

Escape Special Characters APEX Demo

A few weeks ago I wrote more detail than expected regarding escaping of special characters.

I thought I'd add a simple demonstration, for reference.

Consider the following query, with variations of escaped column output.
with data as 
(select q'[G'day,]'||chr(10)
||'<br>APEX<script></script>' as string
from dual)
-- UI default
string dflt
-- where no tags expected
,apex_escape.html(string) protected
-- good for most things
,apex_escape.html_whitelist(string) whitelisted
-- replace line feeds with HTML line break. (more...)

Temporal validity and open/closed intervals

A short while ago I created a SQL quiz for Oracle Dev Gym (PL/SQL Challenge) demonstrating the use of temporal validity and VERSIONS PERIOD FOR syntax to create a "change report" for changes in item prices. Use of temporal validity makes this easier, shorter and more readable code, but even though I thought I had it all covered, player Iudith Mentzel pointed out a tiny quirk I'd overlooked.

You see, the "change in price" wasn't (more...)

APEX Plugin: Calendar Heatmap Region

I was looking at the GitHub "contribution chart", which shows number of commits per day as a heatmap calendar. I thought this type of chart would be cool to have as an APEX plugin, so I went ahead and implemented it.

Here is a video I recorded to walk through how the plugin was made:

Note: For an alternative implementation, see the "Block Calendar" in Oracle JET. As far as I can tell, there (more...)

Powerless Javascript

I was writing a small javascript function, part of which needed to evaluate 10 to the power of a parameter – I couldn’t remember what the exponentiation operator is in javascript so as usually I hit F12 and typed the following into the console:



Wrote and tested the code, checked in to source control. Job done.

A few days later we deployed a new release that included dozens of bug fixes into UAT for testing. (more...)

Announcing the SQL Annual Championship for 2016

I've been making SQL quizzes for years now over at the Oracle Dev Gym (or PL/SQL Challenge as it started out as.) Every year I really have to work my few braincells hard when it is time for the annual championships. The players that have made it through at year and managed to rank in the top are awesome at SQL, so I have to write some really hard quizzes for the championship.

But (more...)

Re-evaluating APEX Authorization Schemes

Authorization schemes in Oracle APEX are used to control access to page, buttons, and all sorts of other components.

In my experience, these are best defined at a privilege level, where the same privilege could be allocated to multiple business roles, but that's for another post.

In this post, I want to mention a cool API function called apex_authorization.reset_cache, which helps control the behaviour of these authorization schemes.


While googling something else (more...)

Cloud Data Warehousing: Is it for real?

  Our industry is full of hype and hyped terms. Big Data. NoSQL. The Cloud. Self-service <whatever>. And Cloud Data Warehousing. Some of the offerings and solutions are real. Some less so. Newest on the scene is cloud data warehousing (or data warehousing in the cloud). As with all new tech, there are a variety […]

Zur Semantik des USE_NL Hints

Ich erinnere mich, dass Jonathan Lewis diesen Punkt schon häufiger erwähnt hat, aber offenbar hatte er tatsächlich noch keinen Artikel dazu geschrieben, und dies jetzt nachgeholt: häufig sieht man in Oracle SQL-Queries Hints der folgenden Form:
use_nl(t1 t2)
Und es gibt wohl in der Tat viele Verwender, die davon ausgehen, dass man den Optimizer damit anweist, einen NESTED LOOPS Join zu verwenden, bei dem t1 via NL Join mit t2 verknüpft wird, wobei t1 die (more...)

New Year, New Look – Get a New UI on Us

Looks DO matter! Today’s users are fed up with the current look and feel of their Oracle Forms / EBS System, many of which were developed last century.  But we know how hard it can be to take the first step towards modernization. As Forms administrators / DBA’s your management many not want to believe there is any life left in these applications and won’t move forward. He probably thinks its wiser to move on. But (more...)

The Relational Data Model

Mid-eighties. I was studying Computer Science. Little did I know back then that this thing called "The Relational Data Model" (RDM) would become huge in the IT-industry. The topic was still hot in academia at that time. My luck was that I liked those courses. Predicate Logic, Set Theory, Database Design, SQL. I aced them all. It was no surprise then, that I ended up working with Oracle software

How to add an NCSA style Access Log to ORDS Standalone

What ORDS Standalone is      ORDS Standalone webserver which is Eclipse Jetty, .  For the standalone, ORDS sends output to STDOUT, it runs on the command line.  That means there's nothing like a control commands like startup, shutdown,status nor log files, access logs.  It's bare bones intentionally to get up and running fast.  Then it's recommended for anything with