Hi guys, I'm going to develop a survey application with the following functionalities:
•An administrator defines a custom form through a form builder interface to carry out a survey. The form can be composed of an arbitrary number of questions (the form of text boxes, radio and check boxes only). The only field that will always be present is the email address of the respondent. •The form is displayed to the respondents •The respondents fill the form and the data are saved in the database While I have a rough idea on how the form builder should look like (http://jacobian.org/writing/dynamic-form-generation/), I struggle to figure out which is the best approach to save the data back in the database (ie, how the model should look like). I figured out 3 possible approaches: 1. save each answer to each question of each survey as a separate record in the database, using a model like, eg, email_address, survey_id, answer. 2. save each form of each survey as a separate record in the database. Assuming that the number of question will be always, let’s say, lower than 50, I could create a model like email_address, survey_id, answer_to_question_1, …, answer_to_question_50 and use only the first n fields, depending on how many questions the specific survey has 3. Create a dynamic model. Once the form structure has been defined by the administrator -assuming is not going to be modified anymore once saved - I could create a new model and the corresponding table in the db, named eg survey_id with the exact fields that I need to save the form. I feel the approach 3) quite unsafe and difficult to implement since I need to give the admin the ability to create and delete tables of the db. The approach 1) seems to be the most flexible, although this means ending up with huge tables in terms of rows. I can easily expect 30 000 respondents per year and 10 to 15 questions per survey. This means to have a table with 450 000 records in a single year, which could some question marks on performances. The approach 2) seems to be the most performance oriented. However, since I need to save the answers from textboxes, radio and checkboxes, I’ll end up to a model with 50 fields defined as CharField with let’s say max_lenght=100, so the table will be quite huge in terms of columns even if a lot of records will use only a limited amount of the available columns (ie, there will be a lot of columns without a real need). I’m not a super expert of DB and Django ORM performances. Taking into consideration the options above and the fact that, at the end I’ll need to run queries over the DB to get reports on the answers for a given survey, what do you suggest? Is there any other approach I’m missing? Thanks for your help. Cheers, P. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
