Thanks Massimo.
Is the second point regarding the shell I raise a known issue as well? From: web2py@googlegroups.com [mailto:web2py@googlegroups.com] On Behalf Of Massimo Di Pierro Sent: Tuesday, 26 February 2013 4:36 PM To: web2py@googlegroups.com Subject: [web2py] Re: Many to many relationships we need to che change the book. "owner" is a keyword in postgresql. When we wrote the 4th edition of the book, web2py was not checking by default. recent versions of web2py are checking. On Monday, 25 February 2013 17:02:09 UTC-6, Toby Wilson wrote: Thanks Cliff and Niphlod... appreciate your assistance. I'll go through the book a little slower and get clear on this. In the book it shows an example using the word "owner". When I copy and paste this in, I can't access the database administration option as I get an internal error with the message in the ticket stating: <type 'exceptions.SyntaxError'> invalid table/column name "owner" is a "ALL" reserved SQL keyword Anyway, so I just changed it to "owne" instead and it all works. Another thing, while going through the steps outlined in the book, I've been using the shell in Controllers. I type a line, for example: db.thing.insert(name='Chair', owne=1) and press enter and nothing happens. Then I'll type it again and hit enter and it outputs: In [11] : db.thing.insert(name='Chair', owne=1) 4 Showing that it worked. As I keep doing this and even change what I type in, it only works every second time. One time I hit enter and nothing happens, then after typing I hit enter and it seems to work. Am I doing something wrong or is this a bug in web2py or in my installation perhaps? Toby On Monday, 25 February 2013 18:24:48 UTC+11, Toby Wilson wrote: Hi all, New to web development and web2py. Know a bit of Python. As a learning experience I've written a food tracking program that works really well in Python and it just runs on my local PC. It just reads and writes values into text files. Now I'm trying to transfer that into web2py as a next step learning experience. I'm trying to figure out the database side of it (models). It seems what I'm dealing with is many-to-many relationships. I have a list of meals and each meal has a list of associated ingredients. So one ingredient can be in many meal and each meal has many ingredients. So essentially, what the program I've written can do is add 3 x "Meal 1" to the quantity existing in the database for "Meal 1" and then after doing that prompt the user with: "Do you want this to impact the level of the ingredient 'carrot'?" Y/N And then: "Do you want this to impact the level of the ingredient 'steak'? Y/N etc. And the program knows that "Meal 1" needs 3 carrots, so upon entering "Y" to the first question, 3 carrots are automatically subtracted from the stock level of carrots in the database. So as meals are added, the user is prompted with associated ingredients and can choose to update or not update the level of that associated ingredient. In the local Python program I've written, all of this is just done through listing things in dictionaries and using functions to manipulate the data and then read and write to text files. Now I want to use database tables and I'm not sure how much of the association should be in the model and how much (if any) should be in the controller (for example in the form of a dictionary). I've read through the documentation on many to many relationships but haven't got a full grasp of it yet. I've coded a few different database structures but haven't managed to get it right yet. The way I've been thinking about it is, a table for meals, a table for ingredients, and perhaps a table for associations? I've used "reference" to get the drop down box associated, but I can't select more than ingredient. I had a look at the Django admin login and it visually made this look a bit easier - i.e. building the one to many relationship. How is this done in web2py? Any help or advice would be much appreciated. Toby P.S. If I have a database file in web2py and open the file through the web2py IDE and replace the contents with a totally different database structure and save it, what happens? Does web2py just remove what was there in the database and replace the database tables with the new ones or does it manage it in a different way (i.e. only add new elements etc.)? -- --- You received this message because you are subscribed to the Google Groups "web2py-users" group. 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