Variable reports are very useful to customize your own i-doit installation for your individual needs.
To give an example: Say that your company uses printers which are assigned to certain offices. The rooms 1.01 to 1.07 use Printer A, rooms 1.08 to 1.11 use Printer B.
This can be documented with the custom category Department. This category is assigned to the object type Printer and defined as single-value category, not as list category ("Multi-Value"). The Department attribute is added as Object-Relation (multiple selection) with the addition Share Access.
Then change to the object Printer. Now you can select the assigned rooms in the Department category.
The result in the category is shown in the following picture.
You can also visualize the result with the CMDB explorer.
Mirrored View for Custom Category
But when you have a look at room 1.05 now, how can you find out which printer is assigned to this room? For this purpose, you need a mirrored view with which you can see which printer is related to this room. The variable reports provide a good solution for such context-related queries.
To this end, you set up a report and another custom category. First of all, you create the report Department-related hardware. Check the box Variable Report and select some significant attributes regarding the printers under Output.
The query builder provides the possibility to set a Placeholder for all links which generate relations under Conditions.
In our case this means: The report "searches" for those objects in which the object ID of the currently selected object is listed in the custom category Department in the attribute Department. But what is the selected object? There is no selected object in the context of the report manager.
Therefore you always have to select an object to be able to fill out the report. You can achieve this by creating a category for the report which executes the report within an object. This is called Department, assigned to the object Room and defined as single-value category. There also is an unnamed attribute with the Field type Report. The ID of the above mentioned report is specified under Addition.
The report ID is contained in the overview of the already defined reports.
Now the new category is available in room objects. It always generates the report for the object in which the user currently is. By this means, you get a mirrored view of the relation to the department.