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#Data Model

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A database model is a type of data model that determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized and manipulated. The most popular example of a database model is the relational model, which uses a table-based format.

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Article
Robert Cemper · Jul 21, 2020 2m read
Un-Typical persistence 
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 !

During my search for a snapshot of a persistent object,
I met a feature that I would like tho share as it could be useful in some special situations.
My trigger was to have a before- and an after-image during unit testing.

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Introduction

The field test of Caché 2016.2 has been available for quite some time and I would like to focus on one of the substantial features that is new in this version: the document data model. This model is a natural addition to the multiple ways we support for handling data including Objects, Tables and Multidimensional arrays. It makes the platform more flexible and suitable for even more use cases.

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Over the past year or so, my team (Application Services at InterSystems - tasked with building and maintaining many of our internal applications, and providing tools and best practices for other departmental applications) has embarked on a journey toward building Angular/REST-based user interfaces to existing applications originally built using CSP and/or Zen. This has presented an interesting challenge that may be familiar to many of you - building out new REST APIs to existing data models and business logic.

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Article
Iryna Mykhailova · Aug 2, 2022 8m read
Data models in InterSystems IRIS

Before we start talking about databases and different data models that exist, first we'd better talk about what a database is and how to use it.

A database is an organized collection of data stored and accessed electronically. It is used to store and retrieve structured, semi-structured, or raw data which is often related to a theme or activity.

At the heart of every database lies at least one model used to describe its data. And depending on the model it is based on, a database may have slightly different characteristics and store different types of data.

To write, retrieve, modify, sort, transform or print the information from the database, a software called Database Management System (DBMS) is used.

The size, capacity, and performance of databases and their respective DBMS have increased by several orders of magnitude. It has been made possible by technological advances in various areas, such as processors, computer memory, computer storage, and computer networks. In general, the development of database technology can be divided into four generations based on the data models or structure: navigational, relational, object and post-relational.

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Article
Rob Tweed · Dec 20, 2021 1m read
Holiday Reading: What Lies Beneath!

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.

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Hey developers!

Sometimes we need to insert or refer to the data of classes directly in globals.

And maybe a lot of you expect that data structure of global with records is:

^Sample.Person(Id)=$listbuild("",col1,col2,...,coln).

And this article is a heads up, that this is not always true, don't expect it as granted!

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Article
Dmitrii Kuznetsov · Feb 15, 2021 17m read
Four Database APIs

A concurrent session in IRIS:
SQL, Objects, REST, and GraphQL

Kazimir Malevich, "Athletes" (1932)

"But of course you don't understand! How can a person who has always traveled in a horse-drawn carriage understand the feelings and impressions of the express traveler or the pilot in the air?"

Kazimir Malevich (1916)

Introduction

We’ve already addressed the topic of why object/type representation is superior to SQL for implementing subject area models. And those conclusions and facts are as true now as they have ever been. So why should we take a step back and discuss technologies that drag abstractions back to the global level, where they had been in the pre-object and pre-type era? Why should we encourage the use of spaghetti code, which results in bugs that are hard to track down, and which relies only on virtuoso developer skills?

There are several arguments in favor of transmitting data via SQL/REST/GraphQL-based APIs as opposed to representing them as types/objects:

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In the previous parts (1, 2) we talked about globals as trees. In this article, we will look at them as sparse arrays.

A sparse array - is a type of array where most values assume an identical value.

In practice, you will often see sparse arrays so huge that there is no point in occupying memory with identical elements. Therefore, it makes sense to organize sparse arrays in such a way that memory is not wasted on storing duplicate values.

In some programming languages, sparse arrays are part of the language - for example, in J, MATLAB. In other languages, there are special libraries that let you use them. For C++, those would be Eigen and the like.

Globals are good candidates for implementing sparse arrays for the following reasons:

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Article
Nikolay Soloviev · Aug 1, 2019 3m read
Nested set model for ObjectScript

In many projects I was faced with storing hierarchical data (tree) in classes.
By tree, I mean such data, where each node has a parent node — an object of the same class.
Many examples of such data can be given. For example, a catalog in the online store. Suppose that this online store sells books, in this case, the category tree might look like this:

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Motivation

This project was thought of when I was thinking of how to let Python code deal naturally with the scalable storage and efficient retrieving mechanism given by IRIS globals, through Embedded Python.

My initial idea was to create a kind of Python dictionary implementation using globals, but soon I realized that I should deal with object abstraction first.

So, I started creating some Python classes that could wrap Python objects, storing and retrieving their data in globals, i.e., serializing and deserializing Python objects in IRIS globals.

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Article
Peter Steiwer · Nov 26, 2019 3m read
Designing valid hierarchies in DeepSee

When designing a hierarchy in DeepSee, a child member must have only one parent member. In the case where a child corresponds to two parents, the results can become unreliable. In the case where two similar members exist, their keys must be changed so that they are unique. We will take a look at two examples to see when this happens and how to prevent it.

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Article
Henrique Dias · Jan 13, 2022 4m read
How to find the dataset you need?

Hey community! How are you doing?

I hope to find everyone well, and a happy 2022 to all of you!

Over the years, I've been working on a lot of different projects, and I've been able to find a lot of interesting data.

But, most of the time, the dataset that I used to work with was the customer data. When I started to join the contest in the past couple of years, I began to look for specific web datasets.

I've curated a few data by myself, but I was thinking, "This dataset is enough to help others?"

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Process-private Globals can be used as a data global in storage definition. That way, each process can have its own objects for the class with ppg storage. For example lets define a pool, which can:

  • add elements to a pool (ignoring duplicates)
  • check if an element exists in the pool

Here's the class:

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Headache-free stored objects: a simple example of working with InterSystems Caché objects in ObjectScript and Python

Neuschwanstein Castle

Tabular data storages based on what is formally known as the relational data model will be celebrating their 50th anniversary in June 2020. Here is an official document – that very famous article. Many thanks for it to Doctor Edgar Frank Codd. By the way, the relational data model is on the list of the most important global innovations of the past 100 years published by Forbes.

On the other hand, oddly enough, Codd viewed relational databases and SQL as a distorted implementation of his theory. For general guidance, he created 12 rules that any relational database management system must comply with (there are actually 13 rules). Honestly speaking, there is zero DBMS's on the market that observes at least Rule 0. Therefore, no one can call their DBMS 100% relational :) If you know any exceptions, please let me know.

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Hi everyone,

I want to talk about our project and use the dataset theme for this contest.

Our intention never was to be a data curator, especially because sometimes my precious data means a lot for me, but not for the rest of the world.

My Precious

We want to go a step further and empower the user to find the perfect dataset for their needs.

Our project is a bridge between the data science community and the developer's community using InterSystems IRIS to achieve this mission.

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Let's consider you would like to efficiently store your historical data in a similar structure than the one used for your current data, but without sharing the same physical storage (ie : not in the same global). What is the most efficient way to do it ?

Below a simple class of your current data :

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Connected Data London Conference

TRIADB is an emerging unique and valuable technology in NoSQL database modelling and BI analytics. The following video is from a presentation and demonstration of TRIADB prototype implemented on top of Intersystems Cache database and driven with a CLI in Python (Jupyter-Pandas). In fact this is the second time in the past year that a prototype based on this technology is implemented and demonstrated. The first one was built on top of OrientDB multi-model database and driven by a Mathematica notebook.

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In this article I'd like to share with you a phenomena that is best you avoid - something you should be aware of when designing your data model (or building your Business Processes) in Caché or in Ensemble (or older HealthShare Health Connect Ensemble-based versions).

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