The attached diagram (hopefully) displays what I would like. Say I have a database of pupil-teacher information from a school, two tables: one with pupil-class; the other class-teacher.The first question in the survey asks what class they are in and the pupil selects appropriately. Their answer is then fed into a prepared SQL statement that pulls out those teachers associated with the selected class. These are then fed into the survey software so that the list of appropriate responses for the second question can then be generated.

  Question: Can this be done with LimeSurvey? If so, how can I test it?

You may use an ajax call.
In a question of type "short text" you enter the call
This is a prototype of a call.
In your script "getTeacher.php" you do your queries and return the teachers.
Now the teachers are stored in this questions and you can use them in your survey.
This is possible.

But: What is the number of classes and the number of teachers?
There might be better, shorter ways to do this with built-in features.
So, please, provide a realistic scheme (number of classes, total number of teachers, number of teachers/class (average).

Joffm

Thanks for the reply.

> So, please, provide a realistic scheme (number of classes, total number of teachers, number of teachers/class (average).

There are about 50 classes, 150 teachers, with about 15 teachers per class.

Well, here you can do anything with Expression Script/Manager and Relevance.
Joffm

> Expression Script/Manager and Relevance

I assume these are all searchable in the documentation. What version/level of LimeSurvey allows me to test this?

As you see on the download page, version 4.x. is steill declared as "unstable".
Therefore we always recommend to use version 3.x.