Question

I’ve searched around the web for a way to achieve this, and found multiple solutions. Most of them had messy code, all of them drawbacks. Some ideas involved setting default values of all the db fields based on a record. Others worked by appending multiple SQLFORMs, which resulted in differences in indentation on the page (because it’s 2 HTML tables in 1 form).

I’m looking for a compact and elegant way of providing a read-only representation of a record based on a join on two tables. Surely there must be some simple way to achieve this, right? The Web2py book only contains an example of an insert-form. It’s this kind of neat solution I am looking for.

In the future I will probably need multi-table forms that provide update functionality as well, but for now I’ll be happy if I can get a simple read-only form for a record.

I would greatly appreciate any suggestions.

Answer 1

This seems to work for me:

def test():
  fields = [db.tableA[field] for field in db.tableA.keys() \
      if type(db.tableA[field]) == type(db.tableA.some_field)]
  fields += [db.tableB[field] for field in db.tableB.keys() \
      if type(db.tableB[field]) == type(db.tableB.some_field)]


  ff = []
  for field in fields:
     ff.append(Field(field.name, field.type))

  form = SQLFORM.factory(*ff, readonly=True)

  return dict(form=form)

You could add in field.required, field.requires validtaors, etc. And also, since you’re using SQLFORM.factory, you should be able to validate it and to updates/inserts. Just make sure that the form you are building using this method contains all of the necessary information to validate the form for update — I believe you can add them easily to the Field instantiation above.

EDIT: Oh yeah, and you need to get the values of the record in question to pre-populate the form based on a record id (after form is defined)… also.. I just realized that instead of those list comprehensions, you can just use SQLFORM.factory and provide the two tables:

def test():
  form = SQLFORM.factory(db.tableA, db.tableB, readonly=True)

  record = ... (query for your record, probably based on an id in request.args(0))
  for field in record.keys():
    if (*test if this really is a field*):
      form.vars[field] = record[field]

  return dict(form=form)

Some tweaking will be required since I only provided psuedo-code for the pre-population… but look at: http://web2py.com/books/default/chapter/29/7#Pre-populating-the-form and the SQLFORM/SQLFORM.factory sections.