The Art of Mapping Globals to Classes 1 of 3

Looking to breathe new life into an old MUMPS application?  Follow these steps to map your existing globals to classes and expose all that beautiful data to Objects and SQL.

By following the simple steps in this article and the next two you will be able to map all but the craziest globals to Caché classes.  For the crazy ones I will put up a zip file of different mappings I have collected over the years.  This is NOT for new data; if you don’t already have existing global please just use the default storage.

NewBie's Corner Session 27 Traversing A Global with $Order Part 1

Welcome to NewBie's Corner, a weekly or biweekly post covering basic Caché Material.

Traversing A Global

Perhaps the most difficult concept in Caché/MUMPS is its Global Structure. This session and several that follow it deals with the Global Structure. However, just presenting the material will not guarantee your understanding of it. You must experiment with the data and concepts that are presented.

In this session, we are going to create a small Global of three levels deep, and then show the code to Traverse the Global.

I joined InterSystems less than a year ago. Diving into ObjectScript and IRIS was exciting, but also full of small surprises that tripped me up at the beginning. In this article I collect the most common mistakes I, and many new colleagues, make, explain why they happen, and show concrete examples and practical fixes. My goal is to help other new developers save time and avoid the same bumps in the road.

1. Getting lost among system classes and where to start

The issue: ObjectScript/IRIS ships with many system classes and packages (%Library, %SYS, %Persistent, %SQL, etc.).

Starting out with ObjectScript, it is really exciting, but it can also feel a little unusual if you're used to other languages. Many beginners trip over the same hurdles, so here are a few "gotchas" you'll want to watch out for. (Also few friendly tips to avoid them)

NAMING THINGS RANDOMLY

We have all been guilty of naming something Test1 or MyClass just to move on quickly. But once your project grows, these names become a nightmare. 

➡ Pick clear, consistent names from the start. Think of it as leaving breadcrumbs for your future self and your teammates.

InterSystems IRIS currently limits classes to 999 properties.

But what to do if you need to store more data per object?

This article would answer this question (with the additional cameo of Community Python Gateway and how you can transfer wide datasets into Python).

The answer is very simple actually - InterSystems IRIS currently limits classes to 999 properties, but not to 999 primitives. The property in InterSystems IRIS can be an object with 999 properties and so on - the limit can be easily disregarded.

I'm participating in the Developing with InterSystems Objects and SQL with Joel Solon. The course is very nice and I will share with you some tips I got during the training. Tips presented in the day 4:

1. All data are stored in Globals and Global names start with ^. Example of global: ^animal. Global can have multiples locations to the data ("sub data"). Example: ^animal(1).
2. ^%* globals are accessible from any system-wide (from any namespace).
3. Globals enables IRIS to support multimodel data (object, relational, document, multidimensional, etc).

This post is the direct result of working with an InterSystems customer who came to me with the following problem:

SELECT COUNT(*) FROM MyCustomTable

Takes 0.005 seconds, total 2300 rows.  However:

SELECT * FROM MyCustomTable

Took minutes.  The reason for this is subtle and interesting enough for me to write a post about.  This post is lengthy, but if you scroll to the bottom I'll write a quick summary, so if you've gotten this far and think you've already read enough, scroll to the end to get the main point.  Check for the sentence in bold.

The best way to list, edit, save and delete globals is using an IDE. Now, it is possible if you use VSCode. It is also possible to save globals using yaml files. Perform the following steps:

1. Get an InterSystems IRIS instance and install the application iris-global-yaml: 

zpm:USER>install iris-global-yaml

2. If you just to want an InterSystems IRIS trial for tests git clone and run on docker:

git clone

3. Go to https://openexchange.intersystems.

Hi developers!

As you probably noticed in IRIS 2021 the names of globals are random.

And if you create IRIS classes with DDL and want to be sure what global was created you probably would want to provide a name.

And indeed you can do it. 

Use WITH %CLASSPARAMETER DEFAULTGLOBAL='^GLobalName' in CREATE Table to make it work. Documentation. See the example below:

Globals, these magic swords for storing data, have been around for a while, but not many people can use them efficiently or know about this super-weapon altogether.

If you use globals for tasks where they truly shine, the results may be amazing, either in terms of increased performance or dramatic simplification of the overall solution (1, 2).

Globals offer a special way of storing and processing data, which is completely different from SQL tables. They were first introduced in 1966 in the M(UMPS) programming language, which was initially used in medical databases. It is still used in the same way, but has also been adopted by some other industries where reliability and high performance are top priorities: finance, trading, etc.

Later M(UMPS) evolved into Caché ObjectScript (COS). COS was developed by InterSystems as a superset of M. The original language is still accepted by developers' community and alive in a few implementations. There are several signs of activity around the web: MUMPS Google group, Mumps User's group), effective ISO Standard, etc.

Modern global based DBMS supports transactions, journaling, replication, partitioning. It means that they can be used for building modern, reliable and fast distributed systems.

Globals do not restrict you to the boundaries of the relational model. They give you the freedom of creating data structures optimized for particular tasks. For many applications reasonable use of globals can be a real silver bullet offering speeds that developers of conventional relational applications can only dream of.

Globals as a method of storing data can be used in many modern programming languages, both high- and low-level. Therefore, this article will focus specifically on globals and not the language they once came from.

The Art of Mapping Globals to Classes (3 of 3)

If you are looking to breathe new life into an old MUMPS application follow these steps to map your globals to classes and expose all that beautiful data to Objects and SQL.

If the above does not sound familiar to you please start at the beginning with the following:

The Art of Mapping Globals 1

The Art of Mapping Globals 2

This example is going to show you how to map a classic parent-child structure.

It's well-known that namespace global mapping helps us to write code independent on database storage details (Caché instance name, directory path). But sometimes we can face problems accessing an unsubscripted global which has subscript level mapping (SLM) defined. Most of such cases are evident and associated with administrative tasks that should be done on database level, but some of them can confuse even an experienced developer. Just to start:

• We can't export such a global using Caché Block format (a.k.a. GOF).
• We can't kill such a global.

Maybe you can continue this list.

My major interest is  Working with Globals in Embedded Python.
So I checked the available official documentation.

#1 Introduction to Globals
an attempt of a generic description of what a global is. Pointing to

#2 A Closer Look at ObjectScript
But where is Embedded Python ?
Way down you see

#3 Embedded Python

3.1 Embedded Python Overview
3.1.1 Work with Globals
Great if you have never seen a Global before
Otherwise a shocking primitive example
3.2 Using Embedded Python
Last hope: >>> but there is just NOTHING visible.
This is more than just disappointing! Even IRIS Native API for Python is more detailed.

The Art of Mapping Globals to Classes (4 of 3)

The forth in the trilogy, anyone a Hitchhikers Guide to the Galaxy fan?

If you are looking to breathe new life into an old MUMPS application follow these steps to map your globals to classes and expose all that beautiful data to Objects and SQL.

If the above does not sound familiar to you please start at the beginning with the following:

The Art of Mapping Globals to Classes (1 of 3)

The Art of Mapping Globals to Classes (2 of 3)

The Art of Mapping Globals to Classes (3 of 3)

This one is for you Joel!

For some years I missed being able to offer, to everybody interested in ObjectScript, a tutorial more or less complete, to start with ObjectScript. Something that could help more and make things easier to those new developers that come to our technology... something intermediate, halfway between the common "Hello World!", that doesn't really get you further, and the "Advanced Training", that is unaffordable because of lack of time,etc.

If there were something truly helpful not only as an introduction to the ecosystem, but as a starting point, as a boost, to really start to walk into ObjectScript and move forward by yourself... wouldn't that be awesome?

InterSystems IRIS supports a unique data structure, called globals, for information storage. Essentially, globals are persistent arrays with multi-level indices, having several extra capabilities—transactions, quick traversal of tree structures, and a programming language known as ObjectScript.

I'd note that for the remainder of the article, or at least the code samples, we'll assume you have familiarised yourself with the basics of globals:

Globals Are Magic Swords For Managing Data. Part 1.
Globals - Magic swords for storing data. Trees. Part 2.
Globals - Magic swords for storing data. Sparse arrays. Part 3.

Order is a necessity for everyone, but not everyone understands it in the same way (Fausto Cercignani)

Disclaimer: This article uses Russian language and Cyrillic alphabet as examples, but is relevant for anyone who uses Caché in a non-English locale. Please note that this article refers mostly to NLS collations, which are different than SQL collations. SQL collations (such as SQLUPPER, SQLSTRING, EXACT which means no collation, TRUNCATE, etc.) are actual functions that are explicitly applied to some values, and whose results are sometimes explicitly stored in the global subscripts. When stored in subscripts, these values would naturally follow the NLS collation in effect (“SQL and NLS Collations”).

Hello community,

I wanted to share my experience about working on Large Data projects. Over the years, I have had the opportunity to handle massive patient data, payor data and transactional logs while working in an hospital industry. I have had the chance to build huge reports which had to be written using advanced logics fetching data across multiple tables whose indexing was not helping me write efficient code.

Here is what I have learned about managing large data efficiently.

Choosing the right data access method.

As we all here in the community are aware of, IRIS provides multiple ways to access data. Choosing the right method, depends on the requirement.

• Direct Global Access: Fastest for bulk read/write operations. For example, if i have to traverse through indexes and fetch patient data, I can loop through the globals to process millions of records. This will save a lot of time.

Set ToDate=+H
Set FromDate=+$H-1 For  Set FromDate=$O(^PatientD("Date",FromDate)) Quit:FromDate>ToDate  Do
. Set PatId="" For  Set PatId=$Order(^PatientD("Date",FromDate,PatID)) Quit:PatId=""  Do
. . Write $Get(^PatientD("Date",FromDate,PatID)),!

• Using SQL: Useful for reporting or analytical requirements, though slower for huge data sets.

In this article you will have access to the curated base of articles from the InterSystems Developer Community of the most relevant topics to learning InterSystems IRIS. Find top published articles ranked by Machine Learning, Embedded Python, JSON, API and REST Applications, Manage and Configure InterSystems Environments, Docker and Cloud, VSCode, SQL, Analytics/BI, Globals, Security, DevOps, Interoperability, Native API. Learn and Enjoy!

Machine Learning

Machine Learning is a mandatory technology to build advanced data analysis and automate manual activities with excellent efficiency.

Introduction

Have you noticed that what ever the model and data structure in databases we cannot escape from the fundamental principle of managing data allocation space with references, i.e. pointer based logic, memory addressing ? Isn’t this the fundamental mechanism of programming languages too ? The problem I see with all these modern NoSQL databases, especially graph databases is that they provide a higher level abstraction for the end developer but they hide and lock completely the access to the low level storage and retrieval mechanism including indexes.

Spoilers: Daily Integrity Checks are not only a best practice, but they also provide a snapshot of global sizes and density. 
Update 2024-04-16:  As of IRIS 2024.1, Many of the below utilities now offer a mode to estimate the size with <2% error on average with orders of magnitude improvements in performance and IO requirements. I continue to urge regular Integrity Checks, however there are situations where more urgent answers are needed.

• EstimatedSize^%GSIZE- Runs %GSIZE in estimation mode.   
• ##class(%Library.GlobalEdit).GetGlobalSize(directory, globalname, .allocated, .used.

I would like to introduce my new project for the Globals Contest. A very new view for the globals browser

For those of you who might be new to IRIS, and even those who have used Cache or IRIS for some time but want to explore beyond its usually-assumed boundaries and practices, you might want to dive into this detailed exploration of the database engine that is at its heart, and discover just what you can really do with it, going way beyond what InterSystems have done with it for you. 

You'll discover that it's actually a hugely powerful yet incredibly simple storage engine that allows you to model any kind of database you wish, once you understand and master its simple, basic principles.

While starting with Intersystems IRIS or Cache, developers often encounter three core concepts: Dynamic Objects, Globals & Relational Table. Each has its role in building scalable and maintainable solutions. In this article, we'll walk through practical code examples, highlight best practices, and show how these concepts tie together. 

1. Working with Dynamic Objects:

Dynamic objects (%DynamicObject and %DynamicArray) allow developers to manipulate JSON-like structures directly in Objectscript. They are especially useful for modern applications that need to parse, transform or generate JSON.

Hi Community,

This article describes the small ZPM module global-archiver.
The goal is to move a part of a global from a database to another database.

Why this package?

A typical use case is read-only data sequentially added to your database that you can never delete.
For example:

• User log access to patient medical data.
• Medical documents versioning.

Depending on the intensive usage of your application, these data could highly increase your database size.

In MX any global can be displayed on a sheet in the form of a table.

We will look at the simplest example (work only with  CACHE-2014+ or IRIS)

Upgrade or install  MX.

Start mx.xlsb  and connect to your namespase with vmx-routines.

After opening first sheet, click button  []   ##class(SYS.Stats.Dashboard).Sample()

Then press button [design-mode]   (top of screen ).

You will see something like this in the top four lines:

M-Formulas works in cells in the process of opening this sheet,  step by step :

• - go to the namespace %SYS    ( zn “%SYS” )
• - set dashboard=##class(SYS.Stats.Dashboard).

In the prior part of this series we have provided introduction to Google MapReduce approach, but still not covered their possible ObjectScript implementation. Which we will start to explain today.

Parallel query hinting boosts certain query performances on multi-processor systems via parallel processing. The SQL optimizer determines when this is beneficial. On single-processor systems, this hint has no effect.

Parallel processing can be managed by:

1.  Setting the auto parallel option system-wide.
   

2. Using the %PARALLEL keyword in the FROM clause of specific queries.
   

Globals as a Graph Data Structure in Python

How to use the IRIS Native API + Python to see globals as a Graph Network Chart.

Iris Globals

Reading the documentation these topics are related to globals:

• A global consists of a set of nodes (in some cases, only one node), identified by subscripts.
• Each node can contain a value.
• ObjectScript includes functions to iterate through the nodes of a global and quickly access values.
• A global is automatically stored in the database. When you assign a value to a node of a global variable, the data is written immediately to the database.