web2py - crud

Transcript of "Web2py tutorial to create db driven application."

    1. Web2py Tutorial This presentation is a summary of the documentation to create a simple database driven application using the web2py pythonframework. The documentation can be found here.
    2. Download and RunDownload the framework from here. Go to thedirectory where you downloaded theapplication, and run python web2py.py.
    3. Choose an Admin Password.
    4. Login to the Admin Interface
    5. Create an Application
    6. Database Modeling
    7. Database Model Implementation We create a table notes, with the columns title, description, author,subject and a publication date. We also mention that the fields title, description,author are required, and that the publication date will be automatically assigned the current time.db.define_table(notes, Field(title, length=200, required=True, requires=IS_NOT_EMPTY()), Field(description, length=2000, required=True, requires=IS_NOT_EMPTY()), Field(author, db.auth_user, required=True, requires=IS_NOT_EMPTY()), Field(subject, length=20,requires=IS_IN_SET((english, philosophy, metaphysics))), Field(pub_date, datetime, default=request.now, writable=False) )
    8. We need functions that handle therequest from user.
    9. Function Definition to handle CRUDoperations. (index)def index(): Makes a db query to select all the notes, orders the notes by the publication date and returns a dictionary to the template, containing all the notes. response.flash = "Welcome to the index view!" notes = db(db.notes).select(orderby=db.notes.pub_date) return dict(notes=notes)
    10. Function Definition contd.. (create)def create(): Generates a form corresponding to the model and renders it, if the form sends some data, the function validates the data and saves the data in the database. response.flash = "This is the create page" form=SQLFORM(db.notes) if form.process().accepted: response.flash = form accepted elif form.errors: response.flash = form has errors else: response.flash = please fill the form return dict(form=form)
    11. Function Definitions contd.. (edit)def edit(): The function pre-populates the data from the note instance that has been requested to be edited and renders it, once client sends in some data, it saves it in the database. note = db.notes(request.args(0)) or redirect(URL(error)) form=SQLFORM(db.notes, note, deletable = True) if form.validate(): if form.deleted: db(db.notes.id==note.id).delete() redirect(URL(index)) else: note.update_record(**dict(form.vars)) response.flash = records changed else: response.flash = Something went wrong! return dict(form=form)
    12. We need to create HTML templates
    13. 2 basic templates would do the job!The previous slide shows how to create atemplate. We need to create a template toshow all the content (index.html) and atemplate to create/edit the content(create.html)The files can be found here.
    14. Its Done!!Its time to reap the fruits of the hard workweb2py just did for us :)The source code is available here.You can share it if you liked it, in case of doubtssend a mail to: contact@fruiapps.com.