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"""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()
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