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"""helloworld.py
Illustrate how to load some data, and cache the results.
"""
from .environment import Session
from .model import Person
from .caching_query import FromCache
# load Person objects. cache the result in the "default" cache region
print("loading people....")
people = Session.query(Person).options(FromCache("default")).all()
# remove the Session. next query starts from scratch.
Session.remove()
# load again, using the same FromCache option. now they're cached,
# so no SQL is emitted.
print("loading people....again!")
people = Session.query(Person).options(FromCache("default")).all()
# Specifying a different query produces a different cache key, so
# these results are independently cached.
print("loading people two through twelve")
people_two_through_twelve = Session.query(Person).\
options(FromCache("default")).\
filter(Person.name.between("person 02", "person 12")).\
all()
# the data is cached under string structure of the SQL statement, *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")).\
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")).\
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")).invalidate()
Session.query(Person).\
options(FromCache("default")).\
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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