This course will become read-only in the near future. Tell us at community.p2pu.org if that is a problem.
Looking to create rich web applications with Python? Python has an excellent web framework called Django that has an passionate and active community behind it. It is production ready and takes care of a lot of the basic demands of a web application such as authentication, templating, and a pythonic interface for databases.
WEBCRAFT
Now that we have some understanding of how to describe a system, let's think a little bit more about the relationships between entities. For those of you who have not dealt with modeling a database before this will help you understand what fields you will need in our database.
As an example let's consider a simplified baseball league. When we were describing systems in the previous task we could say that the following elements exist: leagues, teams, players, and games. What are the entity relationships between these? Let's start from the bottom and work our way up.
Player- Can only play for one team at a time. Example: Jose Reyes plays for the NY Mets
Team - Belongs to only 1 league. Has multiple players. Example: The NY Mets belong to the National League. They have a roster of n players on their team.
Leagues - Has multiple teams. Example: The NY Mets, Philidelphia Phillies, Washington Nationals belong to the National League
Games - Contains any 2 teams from either league. Examle: The NY Mets vs Washington Nationals
So what does this mean for building web applications?
In django (and databases in general), a relationship between models is called a foreign key. These are really important for being able to get the data we want back from our database.
Your assignment:
For those that are confused on this topic please take a look at this excellent example. It goes into much greater detail than I just did. http://uswaretech.com/blog/2010/01/django-models-tutorial/
This can be kind of a tricky subject, but once you get it the next step in building our web application will be easy!
System: Enterprise Reporting Software
Each Client has a FK to a PM, or possibly a OneToMany with multiple PMs.
Each Report is created by and FK'd to a PM
A Report can be saved and run again, so report instances would be FK'd to a Report Type, which contains certain Report Elements (data and charts to be included).
http://uswaretech.com/blog/2010/01/django-models-tutorial/ is broken :'(
Reddit:
Post has a foreign key to a User object
a post is created by one User but a User can have many posts
Post has many Votes (but only one Vote per user per post)
Post has foreign key to a Category object
Comment has a foreign key to a User object
Can we use mindmapping software to help us?
Yes whatever you want to use to help map it out
Yes whatever you want to use to help map it out
Thanks
