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· Nov 29, 2022 6m read
What's HL7v2?!

HL7 (Health Level 7) is a set of technical specifications for computerized exchanges of clinical, financial and administrative data between hospital information systems (HIS). These specifications are variously integrated into the corpus of formal American (ANSI) and international (ISO) standards.

The L7 of HL7 indicates that it is a standard that operates at layer 7, in other words at the application layer, of the OSI model. This means that HL7 does not have to take into account exchange security considerations, or those of message transport (this being ensured by lower-level layers such as SSL/TLS for security or TCP for the transport of data for example). To be more precise, layer 7 supports communications for end-user processes and applications and the presentation of data for user-facing software applications. As the highest layer of the OSI model, and the closest to the end user, layer 7 provides application-specific functions such as identifying communication partners and the quality of service between them, determining resource availability, considering privacy and user authentication, and synchronizing communication, as well as connecting the application to the lower levels of the OSI model.

Returning to the HL7 standard, the HL7 version 2 standard (also known as Pipehat) was originally created in 1989 but is still being used and updated regularly, resulting in versions 2.1, 2.2, 2.3, 2.3.1, 2.4, 2.5, 2.5.1, 2.6, 2.7, 2.7.1, 2.8, 2.8.1, 2.8.2 and 2.9. The v2.x standards are backward compatible (e.g., a message based on version 2.3 will be understood by an application that supports version 2.6) and in higher versions, you will see some fields are left just for it.

Despite it being more than 30 years old, HL7v2 remains the most widely used healthcare interface standard by a large margin according to the HL7.org portal that tells that:

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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.

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Hello,

I found another question on how to change the language for Studio (but it would've been nice to have my actual language used - Ukrainian, since it's available, or was available). Still, I can't seem to figure out how to get rid of gibberish in the menu without changing the Windows settings:

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As you can see in my profile I teach at a university and I wanted to share my take on teaching IRIS (or Caché before it).

It’s been some time but I remember seeing a series of articles by @Yuri Marx earlier this year about the course “Developing with InterSystems Objects and SQL”. He actually gave a brief description of what’s done on Day 1, Day 2, and Day 3 with comments from instructor @Joel Solon. And I thought to myself, it may be interesting to share my experience.

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The first installment of this article series discussed how to read a big chunk of data from the raw body of an HTTP POST method and save it to a database as a stream property of a class. The second installment discussed how to send files and their names wrapped in a JSON format.

Now let’s look closer at the idea of sending large files in parts to the server. There are several approaches we can use to do this. This article discusses using the Transfer-Encoding header to indicate chunked transfer. The HTTP/1.1 specification introduced the Transfer-Encoding header, and the RFC 7230 section 4.1 described it, but it’s absent from the HTTP/2 specification.

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Some readers of my previous article, Caché eXTreme for .NET - direct access to globals from C#, wondered if you could access information not just from the same instance in which you’re working, but also from another instance on the same computer, or from an instance located on another computer in the same local network. Some theorized, correctly, that this would be possible using the Enterprise Cache Protocol (ECP). In this article I’m going to show how it can be done.

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InterSystems states that Caché supports at least three data models – relational, object and hierarchical (globals). On can work with data presented in relational model in a program written on C# the same way one works with any other relational DB. To work with data presented by object model in C# one needs to use .NET Managed Provider or some kind or ORM. And starting with version 2012.2 one can work directly with globals (or use direct access to hierarchical data) via Caché eXTreme for .NET.

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Recently I came across a very strong statement to the effect that InterSystems.Data.CacheClient.dll library works fast because it does not open a TCP/IP connection, instead it works in the same process as a database. It made me pause for quite some time. Firstly because .Net Managed Provider, which utilises this library, opens TCP/IP connection to the database (and it is stated in the documentation "Using .NET and the ADO.NET Managed Provider with Caché"). And secondly, because as far as I know only eXtreme applications attach themselves to the process.

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