Complex test data setup in Fitnesse

I am creating functional specifications using Fitnesse for one of my systems. The system is a typical messaging system following the request/response pattern. Writing Fitnesse for this kind of system is straight forward and falls nicely into the BuildOperateCheck pattern. The only problem is that some types of requests are really really complex which could contain up to a few hundred different data fields. It is obviously not practical to setup all these fields in one table row using the ColumnFixture. I am thinking about how to deal with it.

One approach is to identify a small set of data fields that we will focus on testing on each page and create a fixture table that deals with only that small set of data. For the rest of the fields, we just assign some default values.

It is a reasonable assumption. Because on each Fitnesse page we usually test a specific requirement that most likely only involves several variables. For example, if I am designing a online book purchase system which is very complicated. But one of the requirement is to identify the tax rate. The tax rate are identified by the customer's postal code and county. Thus I only need to include "postal code" and "county" in my fixture table and I will be able to test that requirement.

In some rare cases, even that small set of data does not fit well in one table. In that situation, I managed to use multiple tables to collect the data for building a single request. It takes a little extra work but it makes the page more readable.