That's great! I am completely new to LimeSurvey so I don't know what "custom variables" or the "token table" is. I suppose that "token table" is the table where the answers are stored but anyway I should check the manual for more . Thanks for helping!

Answers data is stored at the lime_survey_12345 table which is created when you activate a survey.
The token table holds participant information and tokens which can be seen as one time passwords, see: docs.limesurvey.org/Tokens&structure=Eng...tions+for+LimeSurvey

Oh I see! So the idea (according to the third approach) is to "over-use" the token table, in the sense that it will do something other than what it's supposed to. I.e. create custom variables in the token table and use them to pre-fill a portion of the answers in the survey, at the time that the survey is loaded. Is this so?
Btw I didn't find anything in the "Tokens" section regarding "custom variables". Should I look somewhere else in the manual?

Well, actually the custom variables have been created exactly for that: to pass information that is already avaible to the questionnaire and work with it (you can use filters based on it, etc).

So if you have a spreadsheet with the contacts and additional information per respondent, that you wouldn't need to ask again (or that you would like them to confirm) you can include this into the token table and this data can then be connected directly to the data from the questionnaire.

In the manual they are called "user-defined attribute fields" and can be found here:
docs.limesurvey.org/Tokens&structure=Eng...ned_attribute_fields

At the token table you can store individual attribute data for each entry, see docs.limesurvey.org/Tokens&structure=Eng...ned_attribute_fields

Hello!

Thank you for your answers!
Mazi wrote:
This is not exactly what I meant
What I meant was to create and use a new table (not lime_survey_12345) in the LimeSurvey DB, which I will populate (somehow) with the data required to pre-fill some fields of the questionnaire. Let's call it prefil_12345. Then, when LimeSurvey would load the questionnaire to show it to the user, it would also load certain fields from the prefil_12345 table. When the user completes the survey, it would be eventually stored in the lime_survey_12345 table (along with the prefiled values).
holch wrote:
So this is great! It is exactly what I was thinking of, albeit the table is already there, and there is no need to create a new one in the DB

Regarding populating the token table with external data, I could create a simple service that fetches the required data from an external file (e.g. txt or xml) or even another DB and put them in there, to be used then by LimeSurvey.

So you create these attribute fields (I suppose that you can create as many as you want), and then you use javascript to load them as pre-filled answers in certain survey questions, at loading time. Got it
And if I want to pre-fill an answer, but this time from the answers of another (answered) survey, rather than from the token table? Can I as well use javascript to load these answers from the lime_survey_12345 table?

yannischris wrote: But why would you like to do this? You would have to choose one of the many answers to the same questionnaire to use as prefil values. Unless you only allow one user to fill the source questionnaire. Anyway, I guess it should be doable but in a less straightforward manner than just using the custom variables.

Yes that's what I had in mind! Imagine that there is a survey that is not user specific, from which I want to extract some pre-filled answers for the user specific ones.

For the first part, I think you don't even have to do it via Javascript. I think "insertans" works with the custom variables as well. But I am not 100% sure there.