def select_and_update():
""""
show how we can select a specific record, and then search and read through several records
"""
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
database = SqliteDatabase('data/personjob.db')
try:
database.connect()
database.execute_sql('PRAGMA foreign_keys = ON;')
logger.info('Find and display by selecting a spcific Person name...')
aperson = Person.get(Person.person_name == 'Susan')
logger.info(f'{aperson.person_name} lives in {aperson.lives_in_town} ' + \
f' and likes to be known as {aperson.nickname}')
logger.info('Search and display all Person with missing nicknames')
logger.info(
'Our person class inherits select(). Specify search with .where()')
logger.info('Peter gets a nickname but noone else')
for person in Person.select().where(Person.nickname is None):
logger.info(
f'{person.person_name} does not have a nickname; see: {person.nickname}'
)
if person.person_name == 'Peter':
logger.info('Changing nickname for Peter')
logger.info('Update the database')
person.nickname = 'Painter'
person.save()
else:
logger.info(f'Not giving a nickname to {person.person_name}')
logger.info(
'And here is where we prove it by finding Peter and displaying')
aperson = Person.get(Person.person_name == 'Peter')
logger.info(
f'{aperson.person_name} now has a nickname of {aperson.nickname}')
except Exception as e:
logger.info(e)
finally:
database.close()
def show_integrity_del():
"""
demonstrate how database protects data inegrity : delete
"""
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
database = SqliteDatabase('../data/personjob.db')
try:
database.connect()
database.execute_sql('PRAGMA foreign_keys = ON;')
logger.info('Try to Delete a person who has jobs...')
with database.transaction():
aperson = Person.get(Person.person_name == 'Andrew')
logger.info(
f'Trying to delete {aperson.person_name} who lives in {aperson.lives_in_town}'
)
aperson.delete_instance()
except Exception as e:
logger.info('Delete failed because Andrew has Jobs')
logger.info(f'Delete failed: {aperson.person_name}')
logger.info(e)
finally:
database.close()
def cant_change_pk():
"""
show that PKs cant be changed (and that there is no error!)
"""
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
logger.info("Back to Person class: try to change Peter's name")
aperson = Person.get(Person.person_name == 'Peter')
logger.info(f'Current value is {aperson.person_name}')
logger.info('Update Peter to Peta, thereby trying to change the PK...')
database = SqliteDatabase('../data/personjob.db')
try:
try:
with database.transaction():
aperson = Person.get(Person.person_name == 'Peter')
aperson.person_name = 'Peta'
aperson.save()
logger.info(f'Tried to change Peter to {aperson.person_name}')
except Exception as e:
logger.info(f'Cant change a PK and caught you trying'
) # not caught; no error thrown by Peewee
logger.info(e)
aperson = Person.get(Person.person_name == 'Peter')
logger.info(f'Looked for Peter: found! -> {aperson.person_name}')
try:
aperson = Person.get(Person.person_name == 'Peta')
except Exception as e:
logger.info(
f'Looking for Peta results in zero records. PK changes are ignored and do not throw an '
f'error!!!!')
logger.info(f'Cant change a PK')
logger.info(
'PK "change" can only be achieved with a delete and new create'
)
finally:
database.close()
def add_and_delete():
""""
show how we can add a record, and delete a record
"""
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
database = SqliteDatabase('../data/personjob.db')
try:
database.connect()
database.execute_sql('PRAGMA foreign_keys = ON;')
logger.info('Add and display a Person called Fred; then delete him...')
logger.info('Add Fred in one step')
new_person = Person.create(person_name='Fred',
lives_in_town='Seattle',
nickname='Fearless')
new_person.save()
logger.info('Show Fred')
aperson = Person.get(Person.person_name == 'Fred')
logger.info(
f'We just created {aperson.person_name}, who lives in {aperson.lives_in_town}'
)
logger.info('but now we will delete him...')
# The record we last got is the one that's kind of like in focus
# So in this case Fred is in focus. He is in the aperson variable.
# so if we say aperson.delete_instance we will be deleting Fred
aperson.delete_instance()
logger.info(
'Reading and print all Person records (but not Fred; he has been deleted)...'
)
# We prove that Fred is gone by showing the logger.info() f string and seeing that
# Fred is not in the database.
for person in Person:
logger.info(
f"{person.person_name} lives in {person.lives_in_town} and likes to be known as {person.nickname}"
)
except Exception as e:
logger.info(e)
finally:
database.close()
def add_and_delete():
""""
show how we can add a record, and delete a record
"""
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
database = SqliteDatabase('../data/personjob.db')
try:
database.connect()
database.execute_sql('PRAGMA foreign_keys = ON;')
logger.info('Add and display a Person called Fred; then delete him...')
logger.info('Add Fred in one step')
new_person = Person.create(person_name='Fred',
lives_in_town='Seattle',
nickname='Fearless')
new_person.save()
logger.info('Show Fred')
aperson = Person.get(Person.person_name == 'Fred')
logger.info(
f'We just created {aperson.person_name}, who lives in {aperson.lives_in_town}'
)
logger.info('but now we will delete him...')
aperson.delete_instance()
logger.info(
'Reading and print all Person records (but not Fred; he has been deleted)...'
)
for person in Person:
logger.info(
f"{person.person_name} lives in {person.lives_in_town} and likes to be known as {person.nickname}"
)
except Exception as e:
logger.info(e)
finally:
database.close()
def setUp(self):
database = SqliteDatabase('data/personjob.db')
database.connect()
database.execute_sql('PRAGMA foreign_keys = ON;')
self.test_person = Person.get(Person.person_name == "Andrew")
