Globals

I have a simple app which tries to establish a connection with a Cache database instance via Global API for Java:

Is there a way to pull a user name and password from the Credentials list that is kept in Ensemble? Right now I have a LDAP user that I have hard coded into my ZAUTHENTICATE, which I would like to get away from.

Some of our interfaces use globals for lookups, but we are currently looking at putting a groups of (document) interfaces in a separate production with a shared ‘Default Database for Routines’ to reduce code duplication.

It's well-known that namespace global mapping helps us to write code independent on database storage details (Caché instance name, directory path).

I have a classname and a property name. I want to know, when I get object value directly from a global, which property corresponds to which position in the $lb structure.

Here's what I got so far:

Hi,

I have a class with around 400k lines and 60 columns. Class storage is Cache SQL storage (Mapped from a global).

 I want to create multiple indices on certain fields.

Is there a way to omit or skip rollback of some data changes during a transaction rollback? Maybe some sort of "autonomous transaction"?

Hi all,

I need to create a routine to modifiy some values in a global.

My first attempt was:

Hi, colleagues!

Consider you need to put some (less  than 1GB) data to an indexed array and do some data manipulations and calculations with it.

Should I prefer global or local for it?

Globals, these magic swords for storing data, have been around for a while, but not many people can use them efficiently or know about this super-weapon altogether.

If you use globals for tasks where they truly shine, the results may be amazing, either in terms of increased performance or dramatic simplification of the overall solution (1, 2).

Globals offer a special way of storing and processing data, which is completely different from SQL tables. They were first introduced in 1966 in the M(UMPS) programming language, which was initially used in medical databases. It is still used in the same way, but has also been adopted by some other industries where reliability and high performance are top priorities: finance, trading, etc.

Later M(UMPS) evolved into Caché ObjectScript (COS). COS was developed by InterSystems as a superset of M. The original language is still accepted by developers' community and alive in a few implementations. There are several signs of activity around the web: MUMPS Google group, Mumps User's group), effective ISO Standard, etc.

Modern global based DBMS supports transactions, journaling, replication, partitioning. It means that they can be used for building modern, reliable and fast distributed systems.

Globals do not restrict you to the boundaries of the relational model. They give you the freedom of creating data structures optimized for particular tasks. For many applications reasonable use of globals can be a real silver bullet offering speeds that developers of conventional relational applications can only dream of.

Globals as a method of storing data can be used in many modern programming languages, both high- and low-level. Therefore, this article will focus specifically on globals and not the language they once came from.

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:

Beginning - see Part 1.

3. Variants of structures when using globals

A structure, such as an ordered tree, has various special cases. Let's take a look at those that have practical value for working with globals.

3.1 Special case 1. One node without branches

I know the process ID< and I know the global name: ^||testing(index).  From the terminal (and therefore, and different process ID), how do I view the contents of ^||testing() ?

The Art of Mapping Globals to Classes (4 of 3)

The forth in the trilogy, anyone a Hitchhikers Guide to the Galaxy fan?