New post

#Data Model

7

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.

Learn more.

Hi

I have an Ensemble Application with many classes and relationships between those classes.

I need a tool that can connect to Cache/Ensemble and create a visual ERD from the class definitions within a particular Cache Namespace

MS-Access is one option but it does not automatically create the relationship connectors between classes

Any suggestions

Nigel Salm

0 6
0 5K

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.

13 12
0 2.6K
Article
· Apr 5, 2022 4m read
Serializing Python objects in globals

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.

Open Exchange app
6 1
1 2.2K

Hi,

I would like to know if anyone has had some experience in building systems for multiple end-users.

To keep things simple, in a hypothetical example, say an Event Booking System, where a Venue could sign up to use such a system and define it's Venue, costs, calendars, etc.. and then invite their customers to book the Venue on different days/times.

If I wish to offer such a system to many Venues, there are a number of options available.

0 6
0 1.7K

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.

Open Exchange app
12 34
6 1.5K
Article
· 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.

15 5
3 1.5K

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:

8 3
1 1.3K
Question
· Mar 13, 2018
DICOM to HL7

We have a case where a vendor can send us more information in the DICOM message rather than in the HL7 result message. In theory it should be possible to take a DICOM and convert it to HL7, stupid question is has anyone done it before? Does anyone have any good examples of a DTL they did to show me how to setup the message structures and translation?

Thanks

Scott Roth

The Ohio State University Wexner Medical Center

Scott.Roth@osumc.edu

0 2
0 1K
Question
· Mar 5, 2019
PrimaryKey vs Idkey

Just wondering an Insight in the difference between these two indexes

IdKey / PrimaryKey
=================

Property Identifier As %Integer

Index Index1 on Identifier [Idkey]

Index Index2 on Identifier [PrimaryKey]

What's the difference?

1. If I don't have Index1 and only have Index2, then cache does still make its own id.
So how and why do I ever use the PrimaryKey. In Joins ??

1 4
0 950

Hi guys!

As you know there are two (at least) ways to get the stored value of the property of InterSystems IRIS class if you know the ID of an instance (or a record).

1. Get it by as a property of an instance with "Object access":

ClassMethod GetPropertyForID(stId As %Integer) As %String

{

set obj=..%OpenId(stId)

return obj.StringData

}

2. Get it as a value of a column of the record with "SQL access":

0 18
0 929

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:

4 2
0 888
Article
· 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:

Open Exchange app
6 1
1 883
Article
· 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:

9 2
4 882

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.

https://www.youtube.com/embed/BiEAbpCOC1A?rel=0
[This is an embedded link, but you cannot view embedded content directly on the site because you have declined the cookies necessary to access it. To view embedded content, you would need to accept all cookies in your Cookies Settings]

3 0
0 810
Question
· Jun 9, 2016
REST Services Cataloging

I've been building up a REST services API, consisting of a dozen or so classes referenced from a Dispatch class, which has route mappings for the first piece of the URI. I'd like to have the Dispatch class be able to output all of the available Services, with some documentation. Is there something like a %Library resource that I could use to pull this information from each of the classes?

Thanks

Chris

0 7
0 799

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.

4 0
3 789

Hi All, I am a Data Architect and am trying a method of deploying alter statements onto Cache DB.

My Data Modeling tool generates alters as this.. So question is if the Cache has a way to rename table? If so what is it?

ALTER TABLE <SchemaName>.GROUP_TYPE_NODES RENAME TO GROUP_TYPE_10082019140110000
;

This is giving error.

0 4
0 714
Article
· 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.

5 1
0 685

For the benefit of those who want to use the Document Database (DocDB) capabilities within InterSystems IRIS, and specifically the REST API it provides, I put together a Postman Collection that provides samples for several basic calls.

For example:

Open Exchange app
1 0
0 677

Hi, Community!

Suppose I have class A with properties P1 and P2.

I want to introduce class B, which would have same records as Class A, but only one property - P2.

What is the easiest way to manage it assuming that I would like to use Class A to add records and be available for any operations to Users with Role A.

And I would like to introduce class B for Users with role B for read-only access. Preferably they shouldn't even be aware of Class A and P1 existence .

What is the easiest way to introduce it and manage it?

0 10
0 667