Ranges with NULLs 1: starting over

I have written a lot about ranges, mostly based on dates, and I have tried my best to avoid NULLs in "from" and "to" columns. I give up: NULLs are a fact of life and must be dealt with. This means revisiting all my previous work!

ODC Appreciation Day: ansible-oracle

For quite some time I planned to write a short series about automatically deploying Oracle Servers with Ansible – particularly with the module “ansible-oracle“. My Time Thieves didn’t allow that, so today, on ODC Appreciation Day, let me give this short rave on the great contribution by Mikael Sandström to our community! Automate or die! […]

ODC Appreciation Day: Old Blog Posts

FIrst of all, kudos to  Tim Hall. This is one of the great times of the year when all these thankful blogs are posted in a day. If you read nothing else in the blogs all year, picking some of them would not be a bad choice.

Speaking of which, I will talk about being thankful for blogs in general. No, not about the new ones explaining all the new features we get in new (more...)

ODC Appreciation Day : The ever growing toolbox

It's ODC Appreciation Day 😃 !

The day initiated by Tim Hall where Oracle bloggers worldwide make a blog post to show appreciation of the Oracle Developer Community.

This year I won't dive into a specific technical thing in SQL or PL/SQL, but rather I'm appreciating how much my toolbox grows all the time with new bits coming in a steady flow.

I've met database developers that learned SQL-92 20+ years ago and still today use (more...)

ODC Appreciation Day – Comparing JSON, they thought of everything…

Oracle 12c introduced JSON in the database and one of the most recent additions is a function to compare JSON, JSON_EQUAL.

From the documentation:

Oracle recommends that you use BLOB storage.
When I first learned about this recommendation it surprised me. Looking at a BLOB doesn't even remotely look like JSON, so how does JSON_EQUAL deal with a comparison between a BLOB and a string?
I mean how does this:
compare to this:

ODC Appreciation Day : Pattern Matching in SQL

Here’s my contribution to the ODC Appreciation Day.

Pattern Matching in SQL, using the MATCH_RECOGNIZE clause, is one of my favorite features, but only recently I’ve used it “for real”.
MATCH_RECOGNIZE allows us to perform enhanced analysis of row sequences, and to detect sequences that match complex patterns.
This feature gave a significant boost to the analytical capabilities of SQL. It enables solving various types of problems in a simpler way than before, in much (more...)

Custom Syntax Highlighting in SQL Developer

A few years ago I raised an enhancement request for SQL Developer to add custom highlighting, specifically to “grey out” all the calls to logger throughout my code. I blogged about this here.

Oracle SQL Developer 18.3 adds this feature with PL/SQL Custom Syntax Rules – and the best thing is, these rules are enabled by default so you don’t have to do anything. Any calls to logger, dbms_output and apex_debug will be (more...)

ODC Appreciation Day : APEX Workspace Activity Logs

Everything gets a special day these days, and thanks to Tim Hall's encouragement, you can enjoy a vibrant display of appreciation for what the Oracle Developer Community embraces about the technology they use daily.

The first year I talked about Dynamic Actions.
Last year I missed the boat - too busy preparing for some holidays.
This year I'd like to lay down my love for a supply of data every APEX developer has access to:  (more...)

ODC Appreciation Day: why I’m “on Oracle” #ThanksODC

Hamersley Gorge, Karajini National Park, Western Australia. ©2018 Jeffrey Kemp

Pictured: Hamersley Gorge, Karajini National Park, Western Australia

Why is this blog called “Jeff Kemp on Oracle”?

Pretty much my entire career has been underpinned by the Oracle database. My first few I.T. jobs involved maintaining and building Oracle Forms and Reports. SQL and PL/SQL have been my indispensable two-pronged tool since day one and remain so today. Through fortuitous circumstance I had the opportunity to swap Forms for APEX quite a few years (more...)

Transport von SQL Patches

Marco Mischke erläutert in seinem Blog, dass "SQL Patches" bei einer Migration mit Hilfe von "data pump" nicht transportiert werden, da sie nicht zum Schema der Applikation gehören. Das Package DBMS_SQLDIAG enthält aber Prozeduren, mit deren Hilfe man die Patches in einer Tabelle ablegen kann, die sich dann ihrerseits mit "data pump" transportieren lässt. Das ist also kein besonderes Hindernis, aber ein Punkt, den man im Rahmen einer Migration im Auge behalten muss.

Performance von lokalen und globalen Indizes partitionierter Tabellen

Richard Foote hat eine neue Artikel-Serie gestartet, in der er sich mit der Performance lokaler und globaler Indizes für partitionierte Tabellen beschäftigt. Da ich auch zu den Leute gehöre, die globale Indizes weitgehend vermeiden, finde ich Argumente, die für die globalen Indizes sprechen, grundsätzlich interessant:

Overhead für Extended Trace im SQL Server

Da ich ein großer Freund des Tracings von Datenbank-Operationen bin, finde ich Untersuchungen wie die von Nenad Noveljic zum Thema "SQL Server Extended Events Trace Overhead" sehr interessant. Im Artikel wird ein Testszenario vorgestellt, das eine relativ zweckfreie Schleife zunächst ohne und dann mit dem Event "sql_batch_completed" gegenüberstellt. Für diese stark CPU-hungrige Operation ergibt sich eine Verlangsamung um ca. 15% nach der Aktivierung des Events: die Laufzeit steigt von 61 auf 74 Sekunden - wobei (more...)

Oracle Forms to APEX IDE Transition

If you would like a good high level run-down on why Oracle APEX is a great choice to modernise Oracle Forms, have a read of this.

After listening in on the AskTom Office Hours on this topic (make sure you also read the chat transcript), I had a few ideas for posts to help Forms developers transition to APEX, before my Forms knowledge gets too stale!

If you put the Forms & APEX IDEs together, (more...)

Connect Power BI to GCP BigQuery using Simba Drivers

Power BI can connect to GCP BigQuery through its provided connector. However, some reported that they’ve encountered the refresh failure as seen below. Even though the error message suggests that the quota for the API requests per user per minute may be exceeded, some reported that the error still occurs even if with a small dataset is being fetched.

In my case, by simply disabling parallel loading table (Options and settings > Options > Data Load), (more...)

Remove duplicate from APEX collection

One of my favourite SQL analytic functions is row_number(), and I've used it in the past to identify, then remove duplicates.

In this case, I have an APEX collection that represents a session based view history of products/people/events, or whatever your users might be browsing.

I've created an option to consolidate that view history, and remove any record you might have opened more than once.

Collections are a little hard to play with outside (more...)

ORA-01723 für DATE-Angaben

Nach langer Zeit mal wieder etwas Selbsterlebtes, das einen Eintrag zu verdienen scheint - wie man eine CTAS-Operation über das nls_date_format torpedieren kann:

SQL> alter session set nls_date_format = 'dd.mm.yyyy hh24:mi:ss';

Session altered.

SQL> create table t as select to_date(null) col1 from dual;
create table t as select to_date(null) col1 from dual
ERROR at line 1:
ORA-01723: zero-length columns are not allowed

SQL> alter session set nls_date_format = 'DD-MON-RR';

SQL> create table (more...)

Hide region if no data found

I have a diagnostic page where I hide regions that aren't relevant - ie, have no data returned.

Here I create a dynamic action that executes After Refresh of the relevant region.

Dynamic Action definition

The client-side condition evaluates the presence of the .nodatafound class within the region, which is present only when no records are returned.

Inspect element of region with no records

The dynamic action then shows/hides the region, depending on the result (more...)

Add record count to collapsed region

I have a diagnostics page where I wanted to display how many records are in a collapsible region's title.

The following is a simple solution, but will only work properly if all records are displayed, and no pagination is used.
Otherwise, check this past post for alternative methods to get the number of rows in a region.

Pick a column in the region and add a class. I chose "cnt".

Column attribute

To be selective, (more...)

Autonomous Database: Creating an Autonomous Data Warehouse Instance

In my previous post I have shown how quick and easy it is to create an Oracle Autonomous Transaction Processing instance. In this post I want to show that the same applies for an Oracle Autonomous Data Warehouse, short ADW, instance. As a matter of fact, both services are running on the very same Oracle … Continue reading "Autonomous Database: Creating an Autonomous Data Warehouse Instance"

JSON, BLOB column and Check Constraint

Last week I attended Neil Chandler's session on JSON during the POUG conference in beautiful Sopot, Poland.
The JSON Developer's Guide recommends using BLOB for storing data, and this is what Neil also recommended.
I was under the (FALSE!) impression that it was not possible to put an IS JSON check constraint on a BLOB column, simply because I tried once and got an exception. After the session I asked Neil if this was (more...)