====Importing Relationships====

Some systems are extremely complex, and you don't always have the information or the opportunity to get the relationships perfect the first time.

Occasionally, you need to make some significant changes to your ARDI relationship structure. And while the ARDI interface works well for adding a few quick relationships on the fly, it could be quite a chore to add hundreds or even thousands of new relationships to the system.

A relationship import file is a standard text file, but with a specific format.

The file format tries to describe how you'd **draw** the relationship between your assets. Where you'd simply draw a straight line from parent-to-child, or where you'd need to lift the pen and go back to somewhere else.

Let's look at the special symbols that can be used.

===Choosing/Changing the Relationship===

The exclamation mark (!) followed by the name of the relationship you'd like to draw. 

This should be at the start of every import file, and may be present several times if you want to create a single import file that imports several relationships.

For example, to choose the //water// relationship, your first line would look like...

<code>
!Water
</code>

===Drawing a Relationship===

Once you change the relationship, you've then got to specify where to start 'drawing' from. In this case, we'll start from our **Water Supply** and go through to our **Main Water Isolation Valve**

<code>
!Water
Water Supply
Main Water Isolation Valve
</code>

You can continue this path as long as you like - if we add a **Main Water Tank** to the next line, the relationship would go from the supply, through the isolation valve and into the tank.

===Dealing with Forks===

If you've got a relationship that forks in two directions, you can choose if you'd like to create your relationships **depth-first** or **width-first**.

===Depth-First and the @ Symbol===

When creating a relationship in a depth-first manner, you always follow each line to its end before going back up-stream.

You can re-position where you're 'drawing from' by adding the '@' symbol in front of the asset.

<code>
!Water
Water Supply
Main Water Isolation Valve
Main Water Distributor
Fire Suppression System
Sprinklers

@Main Water Distributor
Eye-Wash Stations

@Main Water Distributor
Emergency Showers
</code>

The '@' symbol simply moves the pen - it doesn't create any new relationships. So there's no relationship created between **Sprinklers** or **Eye-Wash Stations** and **Main Water Distributor**.

===Width-First and the + Symbol===

With the width-first approach, you make sure that you fill in //every child asset// every time you reach a fork, before you continue down any of them.

Adding the '+' sign before an asset name tells ARDI that you want to add this **to the same parent as the line before**. 

<code>
!Water
Water Supply
Main Water Isolation Valve
Main Water Distributor
Fire Suppression System
+Eye-Wash Stations
+Emergency Showers

@Fire Suppression System
Sprinklers
</code>

So in the example above, the Fire Suppression System, the Eye Wash Stations and the Emergency Showers are all connected to the Main Water Distributor.