sqlalchemy orm with sqlite demo - Python 2.x
Python and SQL databases example from a Well House Consultants training course
More on Python and SQL databases [link]
Source code: orm_sqlite Module: Y113
# sqlalchemy orm with sqlite demo - Python 2.x
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String
from sqlalchemy.orm import sessionmaker
# are we setting up a new database?
database = "stations.db"
populated = os.path.exists(database)
# Handle command line paramaters
echomode = False
for param in sys.argv:
if param == '-v':
echomode = True
if param == '-r':
populated = False
if param == '-h':
print ("Usage: " + __file__ + " [-h] [-r] [-v]")
# connect to the engine (will create empty file if need be
engine = create_engine('sqlite:///'+database, echo=echomode)
Base = declarative_base()
# define a table and create if need be
__tablename__ = 'stations'
id = Column(Integer, primary_key=True)
name = Column(String)
tlc = Column(String)
postcode = Column(String)
footfall = Column(Integer)
return "Station (code='%s', postcode='%s', footfall='%d', fullname='%s')" % (
self.tlc, self.postcode, self.footfall, self.name)
# create a session
Session = sessionmaker(bind=engine)
session = Session()
# populate the table from a data file if it's new of if the "-r" flag was specified
if not populated:
for line in open("rstats2014.xyz"):
f = line.strip().split('\t')
place = Station(name=f, tlc=f, postcode=f, footfall=int(f[-1]))
if not echomode: print f,
# single query
localplace = session.query(Station).filter_by(tlc='MKM').first()
# multiple query
for instance in session.query(Station).order_by(Station.footfall)[:30]:
print (instance.tlc, instance.footfall, instance.name)
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