Hi and Thanks! I'm just starting with web2py - I read the old book last week and am now doing some preliminary coding.
Here are some initial comments on the new book. More to come as I work with it... I prefer the new layout. The book is easier to read with chapter per page BUT it would be useful to have the section headings at the top with links to the relevant parts of the page. The "Migrations" section starts: We refer to this behavior as a "migration". web2py logs all migrations and migration attempts in the file "databases/sql.log". But doesn't actually define the behaviour. A new section "Record representation" breaks the flow of the previous discussion. I suggest you move this material to the Migrations section, maybe with an introductory sentence so that it stands alone: "If the table does exist but differs from the one being defined, it generates the SQL to alter the table and executes it. If a field has changed type but not name, it will try to convert the data(If you do not want this, you need to redefine the table twice, the first time, letting web2py drop the field by removing it, and the second time adding the newly defined field so that web2py can create it.). If the table exists and matches the current definition, it will leave it alone. In all cases it will create the db.person object that represents the table." Also, web2py Migrations are quite different to Rails Migrations. - Rails migrations are hand-written. Web2py migrations are deduced from changes to the models. - Rais migrations are bi-directional in that they can be reversed - Rails migrations can be applied to another database with the same structure (important). This allows changes in the structure of a development database to be then applied to a production database. Is there a way that web2py migrations can be transferred between copies of a database? (eg. by running SQL statments from the log) Many-To-Many relations: Relations seem to be accessible via a field in the related objects that has the name of the realtion. This selects the set of relations that involve the original object. In the "dog ownership" example, I can do this: p = db(db.person.id==1).select().first() for r in p.ownership.select(): print r.person.name, r.dog.name I couldn't find this functionality documented anywhere, though it is very useful (eg. in forms for enumerating related objects). Or maybe it is somewhere else and I missed it...? Cheers, Stewart On Jul 27, 6:49 pm, mdipierro <mdipie...@cs.depaul.edu> wrote: > This is very very preliminary: > > http://web2py.com/book2 > > It is not editable (yet) and I am still adding material but it does > address a lot of issues. > Please use this thread to add comments in particular: > > What sections are missing? > What needs to be clarified? > Are there spelling errors? > Are there formatting error? > > One more way I could use help: I need all the images done with the old > layout to be redone with the new welcome layout. > > Massimo
