At the heart of IRIS and Cache is a very interesting database architecture that we, at M/Gateway Developments, refer to as "Global Storage".  If you ever wanted to know more about the fundamentals and capabilities of this underlying database, you might want to read a major analysis we've put together:

https://github.com/robtweed/global_storage

Amongst other things you'll discover that:

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Article
Laurel James · Apr 20, 2021 3m read
Why gj :: locate?

You may think it isn’t too difficult to get from label+offset^routine to the actual source line responsible for the error.  For an expert it isn't that hard... most of the time.  But there are enough oddities and special rules that even an expert can get it wrong, whilst spending a lot of time trying to get there.

gj :: locate is the latest tool from George James Software – it debugs any error, class or routine by converting the location of an error in compiled .int code to the corresponding location in your source, and then taking you right there.

Image this scenario…

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Article
John Murray · Mar 17, 2017 1m read
Portal tip: System Mode

If you work with Portal on multiple instances of Caché, Ensemble or HealthShare you might find it useful to set the System Mode of the various instances, so as to give yourself a visual reminder of the role of the one you're currently working on.

For instance:

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In Studio you could open a class directly via it's name, without having to traverse the package tree with multiple clicks until arriving at the desired class.

You would Ctrl + O or (File -> Open) and be able to simply type in the class name, for example:

You press Enter, and viola - the class is opened.

How do you achieve this in VSCode?

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InterSystems states that Caché supports at least three data models – relational, object and hierarchical (globals). On can work with data presented in relational model in a program written on C# the same way one works with any other relational DB. To work with data presented by object model in C# one needs to use .NET Managed Provider or some kind or ORM. And starting with version 2012.2 one can work directly with globals (or use direct access to hierarchical data) via Caché eXTreme for .NET

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Article
Timothy Leavitt · Jul 8, 2020 7m read
Tips for debugging with %Status

Introduction

If you're solving complex problems in ObjectScript, you probably have a lot of code that works with %Status values. If you have interacted with persistent classes from an object perspective (%Save, %OpenId, etc.), you have almost certainly seen them. A %Status provides a wrapper around a localizable error message in InterSystems' platforms. An OK status ($$$OK) is just equal to 1, whereas a bad status ($$$ERROR(errorcode,arguments...)) is represented as a 0 followed by a space followed by a $ListBuild list with structured information about the error. $System.Status (see class reference) provides several handy APIs for working with %Status values; the class reference is helpful and I won't bother duplicating it here. There have been a few other useful articles/questions on the topic as well (see links at the end). My focus in this article will be on a few debugging tricks techniques rather than coding best practices (again, if you're looking for those, see links at the end).

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Article
Robert Cemper · Jul 4, 2020 2m read
Terminal Multi-Line Command Editor

The Command extension enables the execution of Multi-Line Commands from Terminal prompt.

Terminal Multi-Line Input with Edit, Insert, Delete, Print extension for IRIS and Caché
IRIS and Caché have just single command lines in terminal available
This Multi-Line Commands Editor also will execute the Multi-line Commands.
In addition, it is independent of access to %SYS and can be installed in any namespace

Special thanks to @Jeffrey Drumm  who inspired me to this and supported me as beta-tester.

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Article
Robert Cemper · Jul 29, 2020 5m read
SQL for ^ERROR Global
This is a coding example working on Caché 2018.1.3 and IRIS 2020.2 
It will not be kept in sync with new versions 
It is also NOT serviced by InterSystems Support !

Standard error logs in IRIS / Caché / Ensemble are written global ^ERRORS.
As this piece dates back some decades back to previous millennium its structure
is far from the typical SQL storage structures.

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Article
Timothy Leavitt · Mar 17, 2021 3m read
Making the most of $Query

I ran into an interesting ObjectScript use case today with a general solution that I wanted to share.

Use case:

I have a JSON array (specifically, in my case, an array of issues from Jira) that I want to aggregate over a few fields - say, category, priority, and issue type. I then want to flatten the aggregates into a simple list with the total for each of the groups. Of course, for the aggregation, it makes sense to use a local array in the form:

agg(category, priority, type) = total

Such that for each record in the input array I can just:

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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

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Article
Robert Cemper · Mar 5, 2021 3m read
Using ECP across IRIS and Caché

Migration from Caché to IRIS can be quite a challenge if your code is grown over many years
and probably not so clean structured as you may like it. So you face the need to check your
migrated code against some reference data. A few samples might not be a problem,
but some hundred GB of data for testing might be.  

A possible step could be to have your fresh code in IRIS but leave your huge datastore on Caché and connect both environments over ECP.  I have created a demo project that gives you the opportunity to try this based on 2 Docker images with IRIS and with Caché connected over ECP.

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Article
Hao Wang · Mar 4, 2021 1m read
What is accuracy, accuracy, recall

Accuracy rate is a measure of our prediction results, and it is a measure of how many of the predicted positive samples are actually positive.
The recall rate is for our original sample, and it shows how many positive examples in the sample were correctly predicted.
Accuracy = Predicted correctly/All
If we want to be able to retrieve as much content as possible, this is the pursuit of "recall ratio", namely A/(A+C), the bigger the better.

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Article
Robert Cemper · Feb 16, 2021 2m read
FOREACH for ObjectScript

As you know ObjectScript has no FOREACH system command nor system function.
But it has a wide room for creativity.

The task is to loop over a global or local array and do something FOR EACH element.

There are 2 possible solutions:
- creating a macro that generates the required code sequences
- creating an Extended Command to perform the action.

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Article
Lily Taub · Mar 19, 2019 9m read
A Tutorial On WebSockets

Intro

Most server-client communication on the web is based on a request and response structure. The client sends a request to the server and the server responds to this request. The WebSocket protocol provides a two-way channel of communication between a server and client, allowing servers to send messages to clients without first receiving a request. For more information on the WebSocket protocol and its implementation in InterSystems IRIS, see the links below.

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While the integrity of Caché and InterSystems IRIS databases is completely protected from the consequences of system failure, physical storage devices do fail in ways that corrupt the data they store.  For that reason, many sites choose to run regular database integrity checks, particularly in coordination with backups to validate that a given backup could be relied upon in a disaster.

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Index to Articles

Hi All

It's been 6 weeks since my original article sad
- - - - -but I have been busy on this project smiley

I have been looking at/thinking about a replacement for ZEN for around 12 months but only really started in depth 4 months ago.
Also been in IT for long enough that I can "get a feel" for a product/technology and make decisions accordingly without going into great detail. 
Any new technology has a learning curve and I don't want to waste time and effort on something that won't fly. 
And, as always, I am looking to minimise the learning curve as I want to concentrate on delivering business benefit. 

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Article
Igor Titarenko · Sep 10, 2020 3m read
How To Create "Write-Only" Code

One of the leading benefits of ObjectScript is the speed and efficiency it allows for an experienced developer. Let's look at an example of how you can benefit from ObjectScript today.

Suppose you have a class that stores the names of your users. We'll call the class Data.User, and give it a string property Name. Next, we will need a method to create a new user or update an existing one. A naive, simplistic approach might look like this example:

 

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The question has come up several times and I saw mixed answers and no quick example

My personal preference is using CPIPE device as you get back exactly the output you will get at the command line interface of your OS .
The tricky thing is to stop reading in time.
The example just displays what you normally see in your console.
it becomes useful if you look for things that you can't get from any $system.whatever()

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When using Studio, ODBC or a terminal connection to Caché or Ensemble, you may have wondered how to secure the connection. One option is to add TLS (aka SSL) to your connection. The Caché client applications - TELNET, ODBC and Studio - all understand how to add TLS to the connection. They just need to be configured to do it.

Configuring these clients is easier in 2015.1 and later. I'm going to be discussing this new method. If you're already using the old, legacy method, it will continue to work, but I would recommend you consider switching to the new one.

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As we all well know, InterSystems IRIS has an extensive range of tools for improving the scalability of application systems. In particular, much has been done to facilitate the parallel processing of data, including the use of parallelism in SQL query processing and the most attention-grabbing feature of IRIS: sharding. However, many mature developments that started back in Caché and have been carried over into IRIS actively use the multi-model features of this DBMS, which are understood as allowing the coexistence of different data models within a single database. For example, the HIS qMS database contains both semantic relational (electronic medical records) as well as traditional relational (interaction with PACS) and hierarchical data models (laboratory data and integration with other systems). Most of the listed models are implemented using SP.ARM's qWORD tool (a mini-DBMS that is based on direct access to globals). Therefore, unfortunately, it is not possible to use the new capabilities of parallel query processing for scaling, since these queries do not use IRIS SQL access.

Meanwhile, as the size of the database grows, most of the problems inherent to large relational databases become right for non-relational ones. So, this is a major reason why we are interested in parallel data processing as one of the tools that can be used for scaling.

In this article, I would like to discuss those aspects of parallel data processing that I have been dealing with over the years when solving tasks that are rarely mentioned in discussions of Big Data. I am going to be focusing on the technological transformation of databases, or, rather, technologies for transforming databases.

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