Did you know that extending the wrong table can multiply the cost of your implementation up to four times?
As an implementation specialist, you need to be aware that there may be some consequent financial costs when you extend ServiceNow tables.
A quick reminder of what are extended tables
I'm regulary amazed by the elegance of ServiceNow's Object-relational database, where tables can be child of another table. Child table inherits all columns and properties of its parent.
The CMDB heavily uses this. At the root level the cmdb_ci table contains only the common fields used for all CMDB items, then it's extended by the cmdb_ci_hardware that adds fields relevant only to hardware, like a serial number. This is extended again by cmdb_ci_computer, that adds a layer of computer centric fields, like OS information or RAM amount.
This allow administrators to implement new business processes rapidly and efficiently, by extending existing tables and customising the child for new usages.
As an implementation specialist, you should be aware of the possible financial costs of your implementations. As technical specialist, it can be very easy to ignore the, often obscure, licensing agreement between the customer and ServiceNow.
Simplified licencing model (2016)
| Type of users | Typical monthly cost per user | Affected tables |
| End-users without any roles | 0$ | |
| Service Management (=ITIL fulfillers) | 100$ | Incident, Change, Problem, CMDB*, Request, Requested Item |
| Service Strategy Worker (=Project fulfillers) | 125$ | Demand, Resource, Project Portfolio, SDLC, Test Apps |
| Platform Runtime (=Fulfillers for your custom table) | 35$ | Any table you create from scratch or from Task |
Hidden financial costs may occur when you extend one of the above tables for a new usage.
As an example, lets say that, for your HR department, you want to create a new process to store internal complaints. Since complaints are a bit like incidents, you create a new u_hr_complaint table from the incident table. This will allow you to benefits from fields like caller and urgency. You create a record producer to allow employees to register their complaints. You set the access controls as to ensure that only the twenty HR employees can read and manage the records.
Since new tables are covered by Platform Runtime, you expect to pay an annual fee of 8,400$ (35$ * 12 months * 20 employees).
When ServiceNow will audit your instance usage, they will inform you that you will billed 24,000$ instead.
Cost comparison of extended table
| Table create | Typical monthly cost per fulfiller | Licensing logic |
| u_hr_complaint, extended from Task | 35$ | Platform Runtime |
| u_hr_complaint, extended from Incident | 100$ | Since it extend an ITIL table, it relates to Service Management |
In this example, HR fulfillers have the exact same access and privileges. They will do the same work, in the same context. But the implementation may trigger an additional and unexpected 15,600$ on the annual fee.
So be aware that if you want to create an Party Events table using ServiceNow, don't extend the Project table to store the events unless you want to multiply the price of your implementation by three or four.
Originally published in servicenow.implementation.blog by Shiva Thomas
