Oracle Offline Persistence Toolkit – Applying Server Changes

Java Tools and Frameworks
| Oct 10, 2018
This is my final post related to Oracle Offline Persistence Toolkit. I will show simple example, which explains how to apply server changes, if data conflict comes up. Read previous post about - Oracle Offline Persistence Toolkit - Submitting Client Changes.

To apply server changes is easier, than to apply client changes. You need to remove failed request from sync queue and fetch server data to client by key.

Example of data conflict during sync:


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Oracle Offline Persistence Toolkit – Submitting Client Changes

Java Tools and Frameworks
| Oct 6, 2018
One of the key topics related to Oracle Offline Persistence toolkit - submitting client changes to backend when data conflict exists. If data was updated on the backend, while client was offline and client wants to submit his changes - we inform about the conflict and ask what client really wants to do. If client choose to submit changes, this means we should push client changes to the backend with the latest change indicator.

There (more...)

Oracle Offline Persistence Toolkit – Before Request Sync Listener

Java Tools and Frameworks
| Oct 2, 2018
One more post from me related to Oracle Offline Persistence Toolkit. I already described how after request listener could be useful to read response data after sync - Oracle Offline Persistence Toolkit - After Request Sync Listener. Today will explain when before request listener could be useful. Same as after request listener, it is defined during persistence manager registration:


Before request listener must return promise. We can control resolved action. For example if there is (more...)

Oracle Offline Persistence Toolkit – After Request Sync Listener

Java Tools and Frameworks
| Sep 28, 2018
In my previous post, we learned how to handle replay conflict - Oracle Offline Persistence Toolkit - Reacting to Replay Conflict. Additional important thing to know - how to handle response from request which was replayed during sync (we are talking here about PATCH). It is not as obvious as handling response from direct REST call in callback (there is no callback for response which is synchronised later). You may think, why you would need (more...)

APEX Static Files not served, ORDS returns 404 or why reading logfiles help

Application Express (APEX)
| Sep 24, 2018

On a recent installation we had problems serving APEX static files (application and workspace), they would always report a 404 not found back from ORDS.

Of course I checked all required DB users and the ORDS config files, but couldn’t find anything obvious. Also no REST service defined in APEX would work.

By looking into the tomcat logfile I found a strange error:

WARNING: ORA-04063: view "ORDS_METADATA.UNIFIED_POOL_CONFIG" has errors

with a whole Java Exception (more...)

Oracle Offline Persistence Toolkit – Reacting to Replay Conflict

Java Tools and Frameworks
| Sep 22, 2018
This is next post related to Oracle Offline Persistence Toolkit. Check my previous writing on same subject - Implementing Handle Patch Method in JET Offline Toolkit. Read more about toolkit on GitHub repo.

When application goes online, we call synchronisation method. If at least one of the requests fails, then synchronisation is stopped and error callback is invoked, where we can handle failure. In error callback, we check if failure is related to the conflict (more...)

ADF BC REST Query and SQL Nesting Control Solution

Java Tools and Frameworks
| Aug 16, 2018
I will talk about expert mode View Object (with hand written SQL), this View Object is created based on SQL join. So, thats my use case for today example. I will describe issue related to generated SQL statement and give a hint how to solve it. This is in particular useful, if you want to expose complex VO (SQL with joins and calculating totals) over ADF BC REST service and then run queries against this (more...)

Oracle Offline Persistence Toolkit – Controlling Online Replay

Java Tools and Frameworks
| Aug 9, 2018
Few months ago I had a post about Oracle Offline Persistence toolkit, which integrates well with Oracle JET (JavaScript toolkit from Oracle) - Oracle JET Offline Persistence Toolkit - Offline Update Handling. I'm back to this topic with sample application upgraded to JET 5.1 and offline toolkit upgraded to 1.1.5. In this post I will describe how to control online replay by filtering out some of the requests, to be excluded from (more...)

Data Conflict Solution for ADF BC REST with Versioning

Java Tools and Frameworks
| Aug 6, 2018
I would like to share sample solution for data conflict processing in ADF BC REST using versioning. When multiple users are editing concurrently the same data row - it is important to inform user before overriding changes already committed by another user. There are other approaches to implement data conflict control, you should evaluate if solution explained below is suitable for your use case, before applying it.

Sample code can be obtained from GitHub repository.

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Text Classification with Deep Neural Network in TensorFlow – Simple Explanation

Java Tools and Frameworks
| Jul 30, 2018
Text classification implementation with TensorFlow can be simple. One of the areas where text classification can be applied - chatbot text processing and intent resolution. I will describe step by step in this post, how to build TensorFlow model for text classification and how classification is done. Please refer to my previous post related to similar topic - Contextual Chatbot with TensorFlow, Node.js and Oracle JET - Steps How to Install and Get It (more...)

Contextual Chatbot with TensorFlow, Node.js and Oracle JET – Steps How to Install and Get It Working

Java Tools and Frameworks
| Jul 10, 2018
Blog reader was asking to provide a list of steps, to guide through install and run process for chatbot solution with TensorFlow, Node.JS and Oracle JET.

Resources:

1. Chatbot UI and context handling backend implementation - Machine Learning Applied - TensorFlow Chatbot UI with Oracle JET Custom Component

2. Classification implementation - Classification - Machine Learning Chatbot with TensorFlow

3. TensorFlow installation - TensorFlow - Getting Started with Docker Container and Jupyter Notebook

4. (more...)

Machine Learning Applied – TensorFlow Chatbot UI with Oracle JET Custom Component

Java Tools and Frameworks
| Jun 11, 2018
This post is based on Oracle Code 2018 Shenzhen, Warsaw and Berlin talks. View presentation on SlideShare:


In my previous post I have outlined how to build chatbot backend with TensorFlow - Classification - Machine Learning Chatbot with TensorFlow. Today post is the next step - I will explain how to build custom UI on top of TensorFlow chatbot with Oracle JET.

You can download complete source code (which includes TensorFlow part, backend for (more...)

Oracle ADF BC REST – Performance Review and Tuning

Java Tools and Frameworks
| May 26, 2018
I thought to check how well ADF BC REST scales and how fast it performs. For that reason, I implemented sample ADF BC REST application and executed JMeter stress load test against it. You can access source code for application and JMeter script on my GitHub repository. Application is called Blog Visitor Counter app for a reason - I'm using same app to count blog visitors. This means each time you are accessing blog page (more...)

Loading Tables with Oracle GoldenGate and REST APIs

Database Management and Performance
| May 14, 2018

With Oracle GoldenGate 12c (12.3.0.1.x), you can now quickly load empty target tables with data from your source database. You could always do this in previous releases of Oracle GoldenGate, but the process has now been simplified using REST APIs and some scripting know-how. In this post, I’m going to show you, high level, how you can use the REST APIs and a bit of scripting to do an initial load (more...)

Creating an Oracle Rest Data Services Docker image

Database Applications Development
| May 14, 2018
Oracle has added Oracle Rest Data Services (ORDS) to the Docker build files family on GitHub, which means that you can now easily dockerize ORDS. If you don’t know yet what ORDS is, it’s a free technology from Oracle that allows you to REST-enable your Oracle databases. More specifically, with ORDS you can just fire … Continue reading "Creating an Oracle Rest Data Services Docker image"

Oracle JET Offline Persistence Toolkit – Offline Update Handling

Java Tools and Frameworks
| Mar 27, 2018
Oracle JET Offline Persistence Toolkit supports offline update, create and delete operations. In this post I will describe update use case. Read previous post related to offline toolkit, where I explain how to handle REST pagination, querying and shredding - REST Paging Support by Oracle Offline Persistence in JET.

This gif shows scenario, where we go to offline mode and then changing data in multiple rows. Data update happens offline and each PATCH request is (more...)

REST Paging Support by Oracle Offline Persistence in JET

Java Tools and Frameworks
| Mar 6, 2018
Oracle Offline Persistence query handler - Oracle Rest Query Handler supports pagination for Oracle ADF BC REST service out of the box. Check my previous post to see how querying works through offline persistence toolkit for ADF BC REST service - Shredding and Querying with Oracle Offline Persistence in JET.

Pagination is a must for large REST resources, its great that Oracle offline persistence toolkit supports it. Let's see it in action.

I navigate through (more...)

Classification – Machine Learning Chatbot with TensorFlow

Java Tools and Frameworks
| Mar 3, 2018
Visual conversation flow is a first thing to create, when you want to build chatbot. Such flow will help to define proper set of intents along with dialog path. Otherwise it is very easy to get lost in conversation transitions and this will lead to chatbot implementation failure. Our chatbot for medical system doesn't make any decisions, instead it helps user to work with enterprise system. It gets user input and during conversation leads to (more...)

Using the Slack webhook API from PL/SQL

Database Applications Development
| Feb 21, 2018
Slack is a web-based chat room popular with many companies. Slack also has an API that can be used to post messages to a given "channel" or chat room. The simplest API offered is the "webhook" integration, which is "a simple way to post messages from external sources into Slack. They make use of normal HTTP requests with a JSON payload that includes the message text and some options."



To create a new Slack (more...)

Shredding and Querying with Oracle Offline Persistence in JET

Java Tools and Frameworks
| Feb 17, 2018
I think offline functionality topic should become a trend in the future. Its great that Oracle already provides solution for offline - Oracle Offline Persistence toolkit. This is my second post related to offline support, read previous post - Oracle Offline Persistence Toolkit - Simple GET Response Example with JET. I have tested and explained with sample app how it works to handle simple GET response offline. While today I would like to go one (more...)