preparation for migrating data to Oracle Virtual Private Database Introduction Recently I was part of a team involved in the preparation of migration data belonging to multiple business units into a single Oracle 19c database with Virtual Private Database (VPD). The VPD solution is used for the virtual separation […]
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How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (1)
What’s in a name? A title is important and I hope that it describes well what I do want to share with you in this series of articles. It is not so much about how to use the back-end part (Oracle Database) or the front-end (Oracle APEX, Java, Node, React […]
SQL–Only Counting Records Sufficiently Spaced apart using Analytics with Windowing Clause and Anti Join
A nice SQL challenge was presented to me by a colleague. The challenges basically consisted of this table. A table contains records that describe login events. Each record has a login timestamp and the identifier of the person logging in. The challenge is to count “unique” login events. These have […]
How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (6)
Last time in “How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (5)”, I told you about Git, Subversion, Maven and Flyway. In this final article, I will discuss the following tools & methods: Oracle SQL Developer, utPLSQL, SonarQube, Perl, Ant and DevOps. Oracle […]
How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (5)
Last time in “How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (4)”, I told you about the Oracle SQL Developer Data Modeler. This time I will discuss the following tools: Git, Subversion, Maven and Flyway. Flyway The first tool I would like to […]
How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (4)
Last time in “How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (3)”, I told you about the Oracle Database and Oracle APEX. This time I will discuss Oracle SQL Developer Data Modeler. Oracle SQL Developer Data Modeler A book I can recommend is Oracle […]
How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (3)
Last time in “How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (2)”, I did show you the database structure. This time I will elaborate on the base tools, the Oracle Database and Oracle APEX. Oracle Database How to use it? I can tell […]
How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (2)
Last time in “How to build an Oracle Database application (that supports APEX, Java, React or any other front-end) (1)”, I gave you an introduction. This time I will elaborate on the database structure. Project folder layout The following top level directories may exist for every database application project: Directory Description […]
Quickly Run NodeJS Demos in Vanilla Windows Sandbox featuring Scoop
TL;DR – this article describes how Windows Sandbox can be used to prepare a well known environment for demonstrations, tutorials, tests etc. Scoop is a great package manager for quickly installing Windows packages (Node runtime, Git client, VS Code editor, …) into the Sandbox. I have applied these concepts to […]
Run Automated Step-by-Step Browser Scenarios for Instruction or Demo from NodeJS applications with Playwright
TL;DR; Run demonstrations or instructions of browser actions. Allow the user to pause and skip acts, and to reset and switch scenarios. Allow the user to interact with the browser before, after and during the scenarios. The open source Playwright library is used from a custom NodeJS application in which […]
How to APIfy WhatsApp – Programmatic interaction with WhatsApp from Node using Playwright
Sending WhatsApp messages from services and applications has been a frequent request from our customers. It also was something I would have liked to use in workshops and demonstrations. It appeals to people. However, WhatsApp does not provide an open API for sending or receiving messages. There is a business […]
How to dynamically Schedule EM Blackouts after PatchTuesday
In the organization I’m currently working for, the OS-patch schedule depends on PatchTuesday (PT) just as Microsoft, Adobe or Oracle are using. And PatchTuesday is, as you all know, the Second Tuesday of each month. But this is a schedule you can not set in the Oracle Enterprise Manager Scheduler. […]
Quickest route to Your First Handson Experience with GraalVM – Katacoda Scenario with live environment and step by step tutorial
TLDR: This Katacoda Scenario has a live runtime environment with GraalVM 20.1 prepared for you including an easy to click-through step by step scenario that does a live demonstration of most aspects of GraalVM (modern Java runtime, Ahead of Time compilation to native executable, polyglot runtime platform and the platform […]
Azure Pipelines: publish to Azure Artifacts
This article is a follow-up to my previous article about using Azure Artifacts for own NPM modules. In that article I showed how to create a NPM module by hand on your local system and publish it to Azure Artifacts. But now we like to integrate it into CI/CD, so […]
Using Azure Artifacts for your own NPM modules
Currently I am working on a customer project in which we build a lot of Azure (serverless) functions, mostly in Javascript. Sometime ago we foresaw that we need some shared functionality which was to be used in multiple functions. So wouldn’t it be a good idea to create some shared […]
Override Date.now() based on OS time when Node returns incorrect current date
I was facing a weird issue. In my Node application – version 10.6.3 – running on Ubuntu – 18.04 – I got the wrong value for the current date and time. A call to new Date() and to Date.now() resulted in a wrong value, off by over two months: The […]
Finally, sftp from an Oracle database using plain plsql
Just a quick blog to get me through the Christmas eve. More than 5 years ago I wrote a blog about FTPS from an Oracle databse. In that blog I already mentioned that SFTP using plsql is possible. Not loading some Java classes in the database and adding some plsql […]
Node JS application running on GraalVM – interoperating with Java, Python, R and more
When you install GraalVM, one of the things you get is a Node runtime environment (GraalVM 19.2.1 is based on Node 10.16.3 – with support for the core Node libraries and un understanding of NPM modules – and has a JavaScript engine that is ECAMScript 2019 compliant). Instead of V8, […]
Python application running on GraalVM and Polyglotting with JavaScript, R, Ruby and Java
GraalVM is among other things a polyglot language runtime. It can run applications written in many languages – JVM languages like Java, Scala, Groovy and Kotlin as well as non-JVM language such as Python, R, Ruby, JavaScript and LLVM. GraalVM also allows applications in any of these languages to execute […]
Create a Native Image Binary Executable for a Polyglot Java Application using GraalVM – using build time class initializing
GraalVM provides a runtime component that enhances the JVM in several ways. It makes the JIT compilation better. It also allows the JVM to run non-JVM languages such as JavaScript, R, Python, Ruby and LLVM. And it makes it possible for languages running on the JVM to interact – through […]
Oracle Database: Write arbitrary log messages to the syslog from PL/SQL
Syslog is a standard for message logging, often employed in *NIX environments. It allows separation of the software that generates messages, the system that stores them, and the software that reports and analyzes them. Each message is labeled with a facility code, indicating the software type generating the message, and assigned […]
Leverage NPM JavaScript Module from Java application using GraalVM
Interoperability from Java to JavaScript has been an objective for the Java community for quite a while. With GraalVM, there is great way to run JavaScript code from within Java applications. The interaction itself is faster, more robust and more ‘native’ (rather than bolt-on) than earlier mechanisms. For developers, the […]
Graceful shutdown of forked workers in Python and JavaScript running in Docker containers
You might encounter a situation where you want to fork a script during execution. For example if the amount of forks is dependent on user input or another specific situation. I encountered such a situation in which I wanted to put load on a service using multiple concurrent processes. In […]
JavaScript Pipelining using Asynchronous Generators to implement Running Aggregates
As of ES 2018 (recent browsers or Node 10), JavaScript support asynchronous generators. Generators are functions that return a set of values, one value at a time. These values can be processed inside the code that invokes the generator immediately, as soon as they become available. There is no need […]
JavaScript Generators – How functions return a stream of results, yielding one result at a time
It was through inspecting some Python code that relied quite heavily that I suddenly realized the beauty of the ES6 concept of generators and the yield keyword. A generator function does not return its result all at once but instead an iterator that can be read from, one value at […]
Building a Conference Session Agenda with Oracle APEX – notes on Pivot, Modal Popup and jQuery
AMIS is part of the Conclusion ecosystem of over 20 companies, each with their own specialty and identity. Several times per year, we organize Conclusion on Stage – a conference that spans across the ecosystem. Presenters from most companies under the Conclusion umbrella submit session proposals. Close to 30 sessions […]
Some neat APEX tricks while building a Session Like application for our Conference
AMIS is part of the Conclusion ecosystem of over 20 companies, each with their own specialty and identity. Several times per year, we organize Conclusion on Stage – a conference that spans across the ecosystem. Presenters from most companies under the Conclusion umbrella submit session proposals. Close to 30 sessions […]
Some Notes on my small steps with Oracle APEX
In this article, I will share some of my personal findings and discoveries as I start out building a small APEX application. No experienced developer is likely to learn anything from this article – but first timers like me could perhaps benefit from my findings. Some of the challenges I […]
Quickly developing and hosting your friendly neighbourhood application – for free using … Oracle APEX
My challenge: my wife wants to set up a system for some of our friends and relatives to let each other know about appliances and things they can share as well as objects they offer up [because they plan to get rid of them]. The specifications are fairly straightforward: users […]
Session Catalog for Oracle OpenWorld & CodeOne 2018 in JSON files
The Oracle OpenWorld and CodeOne 2018 conferences took place in the last week of October 2018. Together, over 1500 sessions took place. The session catalog with details for all sessions is accessible at https://events.rainfocus.com/widget/oracle/oow18/catalogcodeone18 – at least at the time of writing. The session information includes title and abstract, track, […]
Querying connected data in Graph databases with Neo4j
TL;DR; · Graph databases are ideal for query use cases with data with complex relationships and layers of connections · Its query language is fast, efficient and allows for retrieval of information at deeper levels of abstraction in the data · Neo4j is currently the most popular Graph database, and […]
Oracle APEX: the low-code and low-cost application middle tier
Oracle APEX is a low code application development framework. It can be used free of charge – either as part of an existing Oracle Database license or running in the free Oracle Database 18c XE product. An Oracle APEX application should be considered a three-tier application – consisting of a […]
Running Reactive Spring Boot on GraalVM in Docker
GraalVM is an open source polyglot VM which makes it easy to mix and match different languages such as Java, Javascript and R. It has the ability (with some restrictions) to compile code to native executables. This of course offers great performance benefits. Recently, GraalVM Docker files and images have […]
Generic Docker Container Image for running and live reloading a Node application based on a GitHub Repo
My desire: find a way to run a Node application from a Git(Hub) repository using a generic Docker container and be able to refresh the running container on the fly whenever the sources in the repo are updated. The process of producing containers for each application and upon each change […]
Java programs as native executables: GraalVM is the answer!
TL;DR: • Using GraalVM Java applications can be compiled into native standalone executables (will be demonstrated). • Native executables of small Java programs startup blazingly fast, use considerably less resources compared to running on JVM and do not even require the JRE or any other kind of runtime apart from […]
Simple CQRS – Tweets to Apache Kafka to Elastic Search Index using a little Node code
Put simply – CQRS (Command Query Responsibility Segregation) is an architecture pattern that recognizes the fact that it may be wise to separate the database that processes data manipulations from the engines that handle queries. When data retrieval requires special formats, scale, availability, TCO, location, search options and response times, […]
Node & Express application to proxy HTTP requests – simply forwarding the response to the original caller
The requirement is simple: a Node JS application that receives HTTP requests and forwards (some of) them to other hosts and subsequently the returns the responses it receives to the original caller. This can be used in many situations – to ensure all resources loaded in a web application come […]
Create a Node JS application for Downloading sources from GitHub
My objective: create a Node application to download sources from a repository on GitHub. I want to use this application to read a simple package.json-like file (that describes which reusable components (from which GitHub repositories) the application has dependencies on) and download all required resources from GitHub and store them […]
Automate calls to SOAP and REST webservices using simple Python scripts
Probably not many people will tell you running batches over webservices is a good idea. Sometimes though, it can be handy to have a script available to generate webservice calls based on a template message with variables and automate processing the response messages. In addition, if you have a large […]
Welcome to the Zoo of programming languages inspired by the Animal Kingdom
Have you ever come across the following challenge? You have to name something; your own project, own product, company, your boat or even your own child. Coming up with the right name is very important since this is something you have worked on for a long time. So the name […]