Juan Antonio

About Juan Antonio Castellanos

Microsoft Architect & Team Leader | Software Development | Blockchain & Cloud Solutions Microsoft Architect & Team Leader with over 20 years of experience in enterprise software development across diverse global industries. Skilled in software architecture, microservices development in Azure, and the integration of blockchain and cryptocurrency technologies. A strong problem solver and team optimizer, I lead and coordinate multidisciplinary teams to drive strategic goals and deliver high-impact solutions. Proficient in Oracle Database, Oracle Apex, NodeJS, Solidity, and web technologies, with a proven track record of managing international projects across countries including Italy, India, Canada, the U.S., Brazil, Russia, Denmark, England, Portugal, and France.

Beyond Words: Teaching APEX to See with Semantic Search

In the first version of our semantic search implementation in Oracle APEX, everything hinged on manually written descriptions. Someone — maybe you, maybe a user — had to describe each image in words. Then we’d send that text to OpenAI to generate embeddings, store those vectors, and use them to build a smarter kind of [...]

2025-06-04T08:40:37+02:00June 4th, 2025|AI, APEX, blog, Oracle|0 Comments

From LIKE to Vector Search: The Evolution Continues.

In the first part of this series, we looked at how to enrich your data with meaning by generating embeddings using OpenAI’s API. We stored those vectors in our Oracle APEX app, laying the groundwork for a smarter kind of search — one that understands concepts, not just words. Now it’s time to go a [...]

2025-05-27T11:47:08+02:00May 28th, 2025|AI, APEX, blog, Oracle|0 Comments

LIKE Is Dead. We Now Speak in Vectors.

Vector Search is a way to find things that are similar—not by matching exact words like a typical SQL LIKE '%cat%' search—but by comparing meaning. The basic idea is this: You take your data (text, images, whatever) and turn it into numbers—a list of numbers, actually—called a vector. Each vector lives in a multi-dimensional space, [...]

2025-05-21T08:58:42+02:00May 21st, 2025|AI, APEX, blog, Oracle|0 Comments

Don’t Panic, It’s Just Your Wallet in APEX

Working with blockchain data in traditional enterprise environments can feel a bit like trying to mix oil and water. Between smart contracts, RPC nodes, ABI files, and all the other moving parts, it’s easy to get lost—especially when your main focus is building applications with Oracle APEX. In our previous article, we tackled this challenge [...]

2025-05-09T10:22:24+02:00May 9th, 2025|AI, APEX, Blockchain, blog, Oracle|0 Comments

Novocoin with Oracle Blockchain: Who Needs a Lambo ?

Oracle Blockchain Platform is a preassembled PaaS solution that enables businesses to quickly deploy and manage blockchain networks. It includes all necessary components such as compute, storage, containers, identity services, and event management, along with an intuitive console for easy administration. Built on Hyperledger Fabric, Oracle enhances this open-source framework with automated provisioning, multi-cloud and [...]

2025-05-05T16:30:48+02:00May 6th, 2025|APEX, Blockchain, blog, Oracle|0 Comments

Oracle APEX and OpenAI Walk Into a Bar… And Build an Assistant – Part 2

Building on our previous discussion about integrating OpenAI Assistants with Oracle APEX, this article focuses on structuring and displaying user interactions efficiently. Instead of frequent database queries, APEX collections provide session-based storage for optimized performance. The PR_LOAD_MESSAGES procedure initializes the conversation by retrieving system messages, structuring collections, and handling errors. Messages are displayed dynamically using [...]

2025-04-22T11:24:13+02:00April 24th, 2025|AI, APEX, blog, Oracle|0 Comments

Oracle APEX and OpenAI Walk Into a Bar… And Build an Assistant – Part 1

Previously, we explored the OpenAI API's completion models, which enabled text generation and language-based automation. Now, we are shifting our focus to OpenAI's new Assistant API, a more structured approach that enhances interactions by integrating memory, function calling, and multi-step reasoning. This new paradigm allows for more sophisticated and context-aware AI-driven assistants that can work [...]

2025-04-22T11:23:51+02:00April 22nd, 2025|AI, APEX, blog, Oracle|0 Comments

Building an Oracle APEX Plugin: A Deep Dive, part 3

Now we need to move on to the JavaScript portion, which forms the core of our proposal: replacing the item's default validation with a fully customized solution tailored to our specific requirements. This step is crucial, as it allows us to override Oracle APEX’s standard validation behavior and implement logic that aligns with the unique [...]

2025-03-24T12:10:47+01:00March 25th, 2025|APEX, blog, Oracle|0 Comments

Building an Oracle APEX Plugin: A Deep Dive, part 2

In our previous article, we briefly introduced custom attributes, but you might be wondering—what exactly are they and why do they matter? Custom attributes in Oracle APEX plugins are user-defined settings that empower developers to significantly extend and customize a plugin's behavior, appearance, and functionality. Defined explicitly when creating the plugin, these attributes become part [...]

2025-03-24T12:11:06+01:00March 19th, 2025|APEX, blog, Oracle|0 Comments

Building an Oracle APEX Plugin: A Deep Dive, part 1

Oracle APEX plugins are a powerful way to extend the platform’s functionality, allowing developers to create custom behaviors, components, and validations tailored to specific needs. In this post, we’ll guide you step by step through the process of building an Oracle APEX plugin. By the end, you’ll have a strong foundation for creating dynamic, reusable [...]

2025-03-24T12:11:32+01:00March 17th, 2025|APEX, blog, Oracle|0 Comments
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