#Object Data Model

For each defined property, query or an index, several corresponding methods would be automatically generated on a class compilation. These methods can be very useful. In this article, I would describe some of them.

In my previous article, we reviewed possible use-cases for macros, so let’s now proceed to a more comprehensive example of macros usability. In this article we will design and build a logging system.

Logging system

Logging system is a useful tool for monitoring the work of an application that saves a lot of time during debugging and monitoring. Our system would consist of two parts:

• Storage class (for log records)
• Set of macros that automatically add a new record to the log

Have some free text fields in your application that you wish you could search efficiently? Tried using some methods before but found out that they just cannot match the performance needs of your customers? Do I have one weird trick that will solve all your problems? Don’t you already know!? All I do is bring great solutions to your performance pitfalls!

As usual, if you want the TL;DR (too long; didn’t read) version, skip to the end. Just know you are hurting my feelings.

Mapping Examples

Clearly if you have a fourth article in the trilogy you need to go for the money grab and write the fifth, so here it is!

What if you could serialize/deserialize objects in whatever format: JSON, XML, CSV,...; attending different criteria: export/import some properties and not others, transform values in this or that way before exporting/importing,...; and all of this without having to change the class definition? Wouldn't that be great??

Well, perhaps it's a goal too ambitious to reach 100% but, exploring this idea, I've developed a bunch of classes that I thought it was good to share. If you want to test, change, modify or improve the code, or just take a look at it, you can do it here. There you'll find a more detailed explanation (see Readme.md)

Today, I was reading some source code, and encountered the following method signature:

Method SendRequestSync(pRequest As %Library.Persistent, ByRef pResponse As %Library.Persistent)

And I immediately thought, why is there a ByRef?

Recently, a partner company started to develop an Angular client for their Cache application. Together, we decided to leverage the power of Caché dynamic objects to exchange JSON encoded data between client and server parts. However, we realized that currently there is a gap in Cache JSON implementation that prevents simple use of traditional registered and persistent classes to exposed their data with the same ease as with XML. I wrote a small JSON adapter, that does the job and bridgers the gap. It's purpose is simple expose data described by a regular Cache class in a one-to-one fashion to a %DynamicObject. On the other hand, when a serialized JSON data comes in, it can be easily deserialized into dynamic object and subsequently bound to regular class by the newly created adapter.

Coming back to the topic of how to minimize journals.

If you want to dynamically serve images as a property of JSON then there is no perfect encoding solution. One method used frequently is to Base64 encode the image. Whilst there are some negatives to doing this, such as data inflation, there are some positives to working with Base64 images inside the browser.

Let's say you have an image placeholder on a web page...

Caché offers a number of methods for going through a collection and doing something with its elements. The easiest method uses a while-loop and lets you fulfill the task in an imperative manner. The developer needs to take care of the iterator, jumping to the next element and checking if the loop is within the collection.

Overview

Encryption of sensitive data becomes more and more important for applications. For example patient names, SSN, address-data or credit card-numbers etc..

Cache supports different flavors of encryption. Block-level database encryption and data-element encryption. The block-level database encryption protects an entire database. The decryption/encryption is done when a block is written/read to or from the database and has very little impact on the performance.

With data-element encryption only certain data-fields are encrypted. Fields that contain sensitive data like patient data or credit-card numbers. Data-element encryption is also useful if a re-encryption is required periodically. With data-element encryption it is the responsibility of the application to encrypt/decrypt the data.

Both encryption methods leverage the managed key encryption infrastructure of Caché.

The following article describes a sample use-case where data-element encryption is used to encrypt person data.

But what if you have hundreds of thousands of records with an encrypted datafield and you have the need to search that field? Decryption of the field-values prior to the search is not an option. What about indices?

This article describes a possible solution and develops step-by-step a small example how you can use SQL and indices to search encrypted fields.

Hello.

The idea of this post is to introduce Frontier: An abstraction layer that allows Rapid REST development.

REQUIREMENTS:

• Caché 2016.2 or higher.
• Frontier.

Why?

Have you ever found yourself dealing with repetitive tasks like mounting objects, serializing them and eventually handling multiple errors for multiple cases? Frontier can boost your development by making you focus on what really matters: your application.

Frontier is made to stop you from WRITE'ing by instead forcing your methods to return values.
It's designed to make you code clean, and you'll see the why pretty soon.

This is the Part 1, where you'll learn he basics about how to work with Frontier. That means at the end of this part you should be capable of

creating GET requests without difficulties. Since this also serves as a way to introduce the framework, I'll be calling this part: Core concepts.

Hi folks,

I've created a datatype class whoch extends from %Library.String with a REGEX parameter and the validation of the value against the regular expression. The class does not support Populate using the regular expression as a template for data population.

There's plenty of goodness in the %-packages InterSystems supplies, and it seems that every new version of Caché brings something new. The browser-based class documentation (a.k.a. Documatic) generally provides a good level of information, but on the basis that "a picture is worth a thousand words" I sometimes want a diagram.

For example, when trying to navigate the %Dictionary package for a project that needed to find out about class definitions, here's one of the UML class diagrams I created.