Why is deleted data still shown in Sqlalchemy Flask? - mysql

Question

I am working on a task to remove the added pages to the postgresql database using sqlalchemy.
The page is getting deleted from the server but fails to get deleted from the database.
here's the function which deletes the page:
def delete_page(self, page_id, application):
# removed
removed_from_everyone = True
# fro campaign_id
for campaign_id in self.bandit_campaigns:
if page_id in self.bandit_pages[campaign_id].keys():
# If the page is active
if self.bandit_pages[campaign_id][page_id]:
removed_from_everyone = False
# check if the page exist adn if it's not used by anyone
if page_id in self.structure.keys() and removed_from_everyone:
del self.structure[page_id]
# for all the campaign
for campaign_id in self.bandit_campaigns:
# puts it in the new structure
del self.bandit_pages[campaign_id][page_id]
application.logger.info(f'page_id: {page_id}')
application.logger.info(f'type page_id: {type(page_id)}')
# remove arm
self.remove_arm(page_id)
application.logger.info(f'pages: {self.pages}')
# Backup of the situation, in this case save only the pages
# pickle.dump(self.structure, open('structure.pickle', "wb"))
# this one store the last know status
# pickle.dump(self.bandit_pages, open('bandit_pages.pickle', "wb"))
try:
pg = Structure.query.filter_by(page_url=page_id)
db.session.delete(pg)
bp = Bandit_pages.query.filter_by(campaign_id=campaign_id)
db.session.delete(bp)
db.session.commit()
except Exception as e:
print("exception in new page deletion", e)
db.session.rollback()
here's the code of Structure and Bandit_page tables creation:
class Structure(db.Model):
__tablename__ = 'structure'
arm_id = db.Column(db.Integer, primary_key=True)
page_url = db.Column(db.String())
def __init__(self, arm_id,page_url):
self.arm_id = arm_id
self.page_url = page_url
class Bandit_pages(db.Model):
__tablename__ = 'bandit_pages'
campaign_id = db.Column(db.String())
arm_id = db.Column(db.Integer)
status = db.Column(db.Boolean, default=False)
__table_args__ = (
PrimaryKeyConstraint('campaign_id', 'arm_id'),
{},)
def __init__(self, campaign_id, arm_id, status):
self.campaign_id = campaign_id
self.arm_id = arm_id
self.status = status
I tried a way to delete them by using a for loop and then deleting it but that didn't help.
Also the function to add pages is similar to the delete page function,so I am unclear where I am making a mistake. Please help me out. Thanks!

Answer 1

You Can Try these Commands ->
db.session.delete(me)
db.session.commit()

Answer 2

Your code is complicated: you use the same loop a few times with the same variable name.
As a result of this you try to remove only the last value from self.bandit_campaigns:
bp = Bandit_pages.query.filter_by(campaign_id=campaign_id)
db.session.delete(bp)
db.session.commit()
Also, I'm not sure that the keys of self.self.bandit_campaigns are you string ids, check this too.
For deleting all elements from self.bandit_campaigns u can use:
db.session.query(Bandit_pages).filter(Bandit_pages.campaign_id.in_(your_list_of_values)).delete()

Answer 3

So I solved the question by myself,Found that it was kind of a trivial mistake which was overlooked.
try:
Structure.query.filter_by(page_url='ml3', arm_id=1).delete() # .all()
#db.session.delete(pg)
Bandit_pages.query.filter_by(campaign_id='96879533', arm_id=1).delete() # .all()
#db.session.delete(bp)
db.session.commit()
db.session.expire_all()
except Exception as e:
print("exception in new page deletion", e)
db.session.rollback()
this piece of code(I changed a few lines) worked fine.