Mapping

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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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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)

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When I start a fresh installed IRIS or a Container I always find Interoperabiliy (aka. Ensemble) mapped to namespace USER.

Is there any utility to remove this mapping by a click ?
unmapping it global by global, routine by routine,  Package by Package is just a boring exercise.

To be clear: I look for a utility inside IRIS.

The external utility is obvious: Notepad (or any other text editor) 
- clean iris,cpf,
- restart IRIS
It's fast, it's efficient, but it's really hardcore.

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If two globals have same structure, how to reuse one CacheSQLStorage-based class to read both locations?

Thanks!

Update:

Let's say we have two globals:

^a(1)="dataa1"
^a(2)="dataa2"

and

^b(1)="datab1"
^b(2)="datab2"

i.e. the structure difference is global name only.

I would like to have two classes TableA and TableB both are inherited from TableAB, and TableAB taking global name as a parameter.

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Article
Robert Cemper · Apr 25, 2020 2m read
Semi-Persistent Classes and Tables

If you define a Persistent Class / Table the class compiler generates for you an appropriate Storage definition.
A different option is to define a SQL mapping for an already existing Global storage.  This has been excellently
explained already in a different series of articles.   The Art of Mapping Globals to Classes 1 of 3

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Suppose you have developed your own app with InterSystems technologies stack and now want to perform multiple deployments on the customers' side. During the development process you've composed a detailed installation guide for your application, because you need to not only import classes, but also fine-tune the environment according to your needs.
To address this specific task, InterSystems has created a special tool called %Installer. Read on to find out how to use it.

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In my Data Transformation, the Target class needs to create a new List of objects (ListOfObj), depending on some conditions of Source class (Source/Target are completely distinct/different classes).

I experimented with Lists of 'primitive' data types (ListOfDT), and I could add new %String items (as an example) to a List of %String property, with "append" action in DT.

Does anyone have an example, or guidance, how to create new Lists of Objects in data transformation?

For example, if I have a 'container' class like this, it works:

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What if you could serialize/deserialize objects in whatever format: JSON, XML, CSV,...; attending different criteria: export/import some properties and not others, transform values in this or that way before exporting/importing,...; and all of this without having to change the class definition? Wouldn't that be great??

Well, perhaps it's a goal too ambitious to reach 100% but, exploring this idea, I've developed a bunch of classes that I thought it was good to share. If you want to test, change, modify or improve the code, or just take a look at it, you can do it here. There you'll find a more detailed explanation (see Readme.md)

Be aware, this is a proof of concept for myself done in spare times, sure it's not robust enough or it can be done much better... but, I was just playing...ok, I could just wait to the new JSON Adaptor (coming soon!) that sure is going to resolve much more scenarios in a cleaner way, but... meanwhile... :-) ...

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Hi, we are a veterinary lab and we use both the LAB and FIN systems of Antrim. Now we are looking to expose the data in a SQL/Object compatible way so we were wondering if same / similar things had been done by other community members already? If so, could you please share your approach / experience / gotchas with us and we are all ears. I can be reached at yang.jiao@antechmail.com . Thank you! 

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image

The InterSystems DBMS has a built-in technology for working with non-structured data called iKnow and a full-text search technology called iFind. We decided to take a dive into both and make something useful. As the result, we have DocSearch — a web application for searching in InterSystems documentation using iKnow and iFind.

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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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Sometimes global mapping of the same globals can be defined in different ways. E.g., I need to define it for 3 globals ^qAuditC, ^qAuditLog, ^qAuditLogC from the same database named APP-NOJOURN. Which approach should be better from the performance point of view?

1) qAudit* => APP-NOJOURN (one record in global mapping table)
or

2) qAuditC => APP-NOJOURN
qAuditLog => APP-NOJOURN
qAuditLogC => APP-NOJOURN (three records in global mapping table)

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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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The following post outlines an architectural design of intermediate complexity for DeepSee. As in the previous example, this implementation includes separate databases for storing the DeepSee cache, DeepSee implementation and settings. This post introduces two new databases: the first to store the globals needed for synchronization, the second to store fact tables and indices.

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Article
Alexey Maslov · Nov 23, 2017 12m read
Where is my global stored?

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:

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The following post outlines a more flexible architectural design for DeepSee. As in the previous example, this implementation includes separate databases for storing the DeepSee cache, DeepSee implementation and settings, and synchronization globals. This example introduces one new databases to store the DeepSee indices. We will redefine the global mappings so that the DeepSee indices are not mapped together with the fact and dimension tables.

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