"""helloworld.py

Illustrate how to load some data, and cache the results.

"""

import environment
from model import Person
from meta import Session, FromCache

# load Person objects.  cache the result under the namespace "all_people".
print "loading people...."
people = Session.query(Person).options(FromCache("default", "all_people")).all()

# remove the Session.  next query starts from scratch.
Session.remove()

# load again, using the same FromCache option. now they're cached 
# under "all_people", no SQL is emitted.
print "loading people....again!"
people = Session.query(Person).options(FromCache("default", "all_people")).all()

# want to load on some different kind of query ?  change the namespace 
# you send to FromCache
print "loading people two through twelve"
people_two_through_twelve = Session.query(Person).\
                            options(FromCache("default", "people_on_range")).\
                            filter(Person.name.between("person 02", "person 12")).\
                            all()

# the data is cached under the "namespace" you send to FromCache, *plus*
# the bind parameters of the query.    So this query, having
# different literal parameters under "Person.name.between()" than the 
# previous one, issues new SQL...
print "loading people five through fifteen"
people_five_through_fifteen = Session.query(Person).\
                            options(FromCache("default", "people_on_range")).\
                            filter(Person.name.between("person 05", "person 15")).\
                            all()


# ... but using the same params as are already cached, no SQL
print "loading people two through twelve...again!"
people_two_through_twelve = Session.query(Person).\
                            options(FromCache("default", "people_on_range")).\
                            filter(Person.name.between("person 02", "person 12")).\
                            all()


# invalidate the cache for the three queries we've done.  Recreate
# each Query, which includes at the very least the same FromCache, 
# same list of objects to be loaded, and the same parameters in the 
# same order, then call invalidate().
print "invalidating everything"
Session.query(Person).options(FromCache("default", "all_people")).invalidate()
Session.query(Person).\
            options(FromCache("default", "people_on_range")).\
            filter(Person.name.between("person 02", "person 12")).invalidate()
Session.query(Person).\
            options(FromCache("default", "people_on_range")).\
            filter(Person.name.between("person 05", "person 15")).invalidate()

