Intro to basic concepts about multi-model database using InterSystems IRIS. You can find more information in InterSystems Developer Hub

What do you need to install?

Git
Docker (if you are using Windows, make sure you set your Docker installation to use "Linux containers").
Docker Compose
Visual Studio Code + InterSystems ObjectScript VSCode Extension

Setup

Build the container

docker compose build

Run the container we will use as our IRIS instance:

docker compose up -d

Examples

(a). Create a table / persistent class

Let's create a new persistent class using VS Code:

Class try.Point Extends %Persistent [DDLAllowed]
{
    Property X;
    Property Y;
}

This persistent class in InterSystems IRIS is also a table.

You could also create the same class using DDL / SQL:

CREATE Table try.Point (
    X VARCHAR(50),
    Y VARCHAR(50)
)

(b). Storage

After compilation, the class would have generated a storage structure, as a persistent class in InterSystems IRIS is also a table.

Pay attention to:

Type: generated storage type, in our case the default storage for persistent objects
StreamLocation - global where we store streams
IndexLocation - global for indices
IdLocation - global where we store ID autoincremental counter
DefaultData - storage XML element which maps global value to columns/properties
DataLocation - global in which to store data

Class try.Point Extends %Persistent [ DdlAllowed ]
{

Property X;

Property Y;

Storage Default
{
<Data name="PointDefaultData">
<Value name="1">
<Value>%%CLASSNAME</Value>
</Value>
<Value name="2">
<Value>X</Value>
</Value>
<Value name="3">
<Value>Y</Value>
</Value>
</Data>
<DataLocation>^try.PointD</DataLocation>
<DefaultData>PointDefaultData</DefaultData>
<IdLocation>^try.PointD</IdLocation>
<IndexLocation>^try.PointI</IndexLocation>
<StreamLocation>^try.PointS</StreamLocation>
<Type>%Storage.Persistent</Type>
}

}

DefaultData is PointDefaultData, it means that the global node has this structure:

1 - %%CLASSNAME
2 - X
3 - Y

So, the global should look like this:

^try.PointD(id) = %%CLASSNAME, X, Y

(c). Have a look at the data

We still have no data.

Open a WebTerminal session.

Let's add one object:

set p = ##class(try.Point).%New()
set p.X = 1
set p.Y = 2
write p.%Save()

You can have a look at the data using SQL in SQL Explorer or even using an external client through JDBC like SQLTools for VS Code.

select * from try.point

Now, you can display the global in WebTerminal or even Global Explorer

zwrite ^try.PointD
try.PointD(1)=$lb("",1,2)

The expected structure %%CLASSNAME, X, Y is set with $lb("",1,2) which corresponds to X and Y properties of our object (%%CLASSNAME is system property, ignore it).

Of course, you can also add a row via SQL:

INSERT INTO try.Point (X, Y) VALUES (3,4)

The global will look like this:

zw ^try.PointD
^try.PointD=2
^try.PointD(1)=$lb("",1,2)
^try.PointD(2)=$lb("",3,4)

Let's delete all the data from the table:

DELETE FROM try.Point

Our global will look like this:

zw ^try.PointD
^try.PointD=2

Only ID counter is left, so a new object/row would have an ID=3. Also our class and table continue to exist.

But, what happens when we run:

DROP TABLE try.Point

It will destroy the table, the class and delete the global:

zw ^try.PointD

Some other example

Now have a look at the class sample.Person class. Can you still find the properties and the storage definition?

Try executing the included sample method by:

do ##class(sample.Person).RunSample()

intersystems-ib / workshop-multimodel-intro