Data Models di web2py MVC Framework

Gua baru belajar web2py nih buat implementasi dan mutasi program tradeERP gua... Web2py ada 3 bagian utama yaitu Models Controller dan View, untuk sementara gua learning Data Models dulu..

Di web2py support many data source... diantaranya Gluon dari Google App Engine, PostgreSQL, Mysql, dan SQLlite (default)


contoh menggunakan Gluon

try:
    from gluon.contrib.gql import *  # if running on Google App Engine
except:
    db = SQLDB('sqlite://storage.db')  # if not, use SQLite or other DB
else:
    db = GQLDB()  # connect to Google BigTable
    session.connect(request, response, db=db)  #  and store sessions there

Deklarasi standar database , table, insert, count, delete, dan update

db = SQLDB(‘postgres://user:password@hostname/db’, pools=10)
db.define_table(‘person’,db.Field(’name’,’string’))
id= db.person.insert(name=’max’)
query=(db.person.id==id)
db(query).count()
db(query).delete()
db(query).update(name=’Max’)
rows = db(query).select(orderby=db.person.name)
for row in rows: print row.name


drop table dan truncate

db.person.truncate()
db.person.drop()

Contoh deklarasi table ,  dan validasi table, serta reference table (foreign key)

db.define_table('products', SQLField('name'), SQLField('description',
                'text'))

# MANY (users) TO MANY (purchases)

db.define_table('purchases', SQLField('buyer_id', db.users),
                SQLField('product_id', db.products), SQLField('quantity'
                , 'integer'))

purchased = (db.users.id == db.purchases.buyer_id) & (db.products.id
         == db.purchases.product_id)

db.users.name.requires = IS_NOT_EMPTY()
db.users.email.requires = [IS_EMAIL(), IS_NOT_IN_DB(db, 'users.email')]
db.dogs.owner_id.requires = IS_IN_DB(db, 'users.id', 'users.name')
db.dogs.name.requires = IS_NOT_EMPTY()
db.dogs.type.requires = IS_IN_SET(['small', 'medium', 'large'])
db.purchases.buyer_id.requires = IS_IN_DB(db, 'users.id', 'users.name')
db.purchases.product_id.requires = IS_IN_DB(db, 'products.id',
        'products.name')
db.purchases.quantity.requires = IS_INT_IN_RANGE(0, 10)

Pretty clean and readable  dibanding JAVA .. hehehehehehe :D

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