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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.

Learn more.

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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Hi,

I have two namespaces

  1. In the first one, I have defined a class which Extends (%Persistent, Ens.Util.MessageBodyMethods), we'll call it NSOne.Msg.Req
  2. In the second namespace NSTwo, I want to use the previous class with something like SET pInput = ##class(NSOne.Msg.Req).%New()

I mapped the NSOne.Msg.Req package in namespace NSOne. In Atelier, I can see NSOne.Msg.Req in my NSOne. But, when I try to execute line 2 above, it tells me :

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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:

Open Exchange app
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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":

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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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Dear Colleagues and Friends,

is there any indication that the .NET object representation of Cache objects (i.e. InterSystems.Data.CacheClient.dll) complies with .NET Standard? I'm planning to extend our existing .NET client/server solution with a mobile option by Xamarin Forms and can't find any significant hints in the internet.

I'm just fooling around a bit and made some expreiments with a REST API and a generic object-to-JSON tier:

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Article
Dmitrii Kuznetsov · Mar 31, 2019 20m read
How to write the home address right?

How Tax Service, OpenStreetMap, and InterSystems IRIS
could help developers get clean addresses

Pieter Brueghel the Younger, Paying the Tax (The Tax Collector), 1640

In my previous article, we just skimmed the surface of objects. Let's continue our reconnaissance. Today's topic is a tough one. It's not quite BIG DATA, but it's still the data not easy to work with: we're talking about fairly large amounts of data. It won't all fit into RAM at once, and some of it won't even fit on the drive (not due to lack of space, but because there's a lot of junk). The name of our subject is FIAS DB: the Federal Information Address System database - the databases of addresses in Russia. The archive is 5.5 GB. And it's a compressed XML file. After extraction, it will be a full 53 GB (set aside 110 GB for extraction). And when you start to parse and convert it, that 110 GB won't be enough. There won't be enough RAM either.

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First time post, also a new Cache developer, hence the <Beginner> tag.

If our data has Predefined terms in a dictionary, and a user can add terms on their own, can the terms exist in different tables?

Lets call the tables "Terms" and the user data in "UserTerms".

If a third class definition has a property of "Term" can it not be either Terms or UserTerms?

I'm leaning towards using a Subclass strategy where the pseudo "Parent" (forgive me) is Dictionary.Term and the child is along the lines of Dictionary.Term.User

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Question
Neerav Adam Verma · 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 ??

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Hi

Just curious to know about the pros and cons of Parent/Child Vs One/Many.

We do use a bit of both.
One big reason we use Parent child is we feel if we delete one global, it gets rid of all child data too and all parent child data is stored in one global. Much easier to manage.

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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

Totally new to IRIS and Cache.

Trying to evaluate it and work out how we could use it.

As a standard application database. Object or relational etc. does not matter.

Issue is ObjectScript.

So:

1) Can we develop, maintain and use an IRIS database and never use ObjectScript i.e. use only Java, Python, C++ interfaces etc. (exactly which one does not matter)? Would that make designing and using the IRIS database more prone to inefficiency and error?

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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.

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Question
Scott Roth · 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

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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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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?

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