This is my model, made with classical mapping, classes A and B are working accordingly
import sqlalchemy as sa
from sqlalchemy.orm import mapper, relationship
from domain.a import A
from domain.b import B
from app_extentions import metadata
a_table = sa.Table(
'a', metadata,
sa.Column('description', sa.String(30), primary_key=True), # I think this is important
sa.Column('value_x', sa.Boolean()),
)
b_table = sa.Table(
'b', metadata,
sa.Column('id', sa.BigInteger, primary_key=True, autoincrement=True),
sa.Column('description', sa.String(50), sa.ForeignKey(a_table.c.description), nullable=False),
sa.Column('value_y', sa.String(20), nullable=True),
)
mapper(A, a_table)
mapper(B, b_table, properties={
'rel': relationship(
A, primaryjoin=(a_table.c.description == b_table.c.description)
),
})
When I do this using pytest
obj1:A = retrieve_A_object() # A is already in the DB, I get it
obj2:B = create_B_object() # this is created now, it is brand new
obj2.rel = obj1
session = get_session()
session.add(obj2)
session.commit()
SQLAlchemy raises an error
def do_execute(self, cursor, statement, parameters, context=None):
> cursor.execute(statement, parameters)
E sqlalchemy.exc.IntegrityError: (psycopg2.errors.UniqueViolation) duplicate key value violates unique constraint "a_pkey"
E DETAIL: Key (description)=('MY DESCRIPTION') already exists.
I know that it's already in the db, I want to save B object
How can i solve this? Why is this happening?
Related
I'm trying to get a server for an app working, but I'm getting an error upon login:
[!] Object '<User at 0x7f12bc185a90>' is already attached to session '2' (this is '3')
It seems the session I'm adding is already on the database. This is the snippet of code that is causing the problem:
#app.route('/login', methods=['POST'])
def login():
u = User.query.filter(User.username == request.form["username"]).first()
if not u or u.password != request.form["password"]:
return error("E1")
s = Session.get_by_user(u)
if s is not None:
db_session.delete(s)
db_session.commit()
print db_session.execute("SELECT * FROM sessions").fetchall()
s = Session(u)
db_session.add(s)
db_session.commit()
return jsonify(s.values)
As you can see, I'm printing the content from the sessions table before trying to add anything, and it is empty! ([])
What else could be causing this?
Here is the 'Session' implementation:
class Session(Base):
__tablename__ = "sessions"
id = Column(Integer, primary_key=True)
user_id = Column(Integer, ForeignKey('users.id'), unique=True)
user = relationship(User)
key = Column(String(50), unique=True)
created = Column(DateTime)
def __init__(self, user=None):
self.user = user
self.key = base64.encodestring(os.urandom(24)).strip()
self.created = datetime.now()
def __repr__(self):
return '<Session %r>' % (self.key)
#property
def values(self):
return {"username" : self.user.username,
"key" : self.key,
"created" : str(self.created),
}
#classmethod
def get_by_key(cls, key):
s = cls.query.filter(cls.key == key).first()
#print datetime.now() - s.created
if s and datetime.now() - s.created > settings.SESSION_LIFETIME:
s = None
return s
#classmethod
def get_by_user(cls, user):
s = cls.query.filter(cls.user == user).first()
if s and datetime.now() - s.created > settings.SESSION_LIFETIME:
s.query.delete()
db_session.commit()
s = None
return s
As #marcinkuzminski mentioned, you can't add an object that is already attached to another session. Just pulling in the original session from the object with object_session() is risky, though, if you aren't sure that session originated in the same thread context you're currently operating in. A thread-safe method is to use merge():
local_object = db_session.merge(original_object)
db_session.add(local_object)
db_session.commit()
Object you're trying to modify is already attached to another session.
Maybe you have wrong imports, and db_session is a new instance.
A good workaround to this is to extract the current bound session and use it:
Instead of:
db_session.add(s)
Do:
current_db_sessions = db_session.object_session(s)
current_db_sessions.add(s)
This db session issue will arise if you are having server.py and model.py importing each other
server.py
from flask import Flask
import os
import models as appmod #################### importing models here in server.py<----------
app = Flask(__name__) # L1
app.config.from_object(os.environ['APP_SETTINGS']) # L2
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False # L3
database = SQLAlchemy(app) # L4
db = database # L5
#app.route('/item_delete/<id>', methods=['DELETE'])
def remove_method(id = None):
data_rec = appmod.Employee.query.get(id)
db.session.delete(data_rec)
db.session.commit()
return "DELETE"
if __name__ == '__main__':
app.run(port=5000, host='0.0.0.0',debug=True,threaded=True)
models.py
from server import db #################### importing server in models.py here <------------
from sqlalchemy.dialects.mysql import JSON
class Employee(db.Model):
__tablename__ = 'employe_flask'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(128))
datetime = db.Column(db.DateTime)
designation = db.Column(db.String(128))
def __init__(self, name, datetime, designation):
self.name = name
self.datetime = datetime
self.designation = designation
#staticmethod
def delete_rec(data_rec):
db.session.delete(data_rec)#.delete
db.session.commit()
def __repr__(self):
record = {"name":self.name,"date":self.datetime.ctime(),"designation":self.designation}.__str__()
return record
Remove the line L1 to L5 from server.py and place it in common file like settings.py
and import 'app' and 'db' to server.py and import db in models.py
like this files below
server.py
from flask import Flask
import os
import models as appmod
from settings import app, db
#app.route('/item_delete/<id>', methods=['DELETE'])
def remove_method(id = None):
data_rec = appmod.Employee.query.get(id)
db.session.delete(data_rec)
db.session.commit()
return "DELETE"
if __name__ == '__main__':
app.run(port=5000, host='0.0.0.0',debug=True,threaded=True)
settings.py
import os
from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
app = Flask(__name__) # L1
app.config.from_object(os.environ['APP_SETTINGS']) # L2
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False # L3
database = SQLAlchemy(app) # L4
db = database # L5
models.py
from settings import db
from sqlalchemy.dialects.mysql import JSON
class Employee(db.Model):
__tablename__ = 'employe_flask'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(128))
datetime = db.Column(db.DateTime)
designation = db.Column(db.String(128))
def __init__(self, name, datetime, designation):
self.name = name
self.datetime = datetime
self.designation = designation
#staticmethod
def delete_rec(data_rec):
db.session.delete(data_rec)#.delete
db.session.commit()
def __repr__(self):
record = {"name":self.name,"date":self.datetime.ctime(),"designation":self.designation}.__str__()
return record
This error means the record you are handling is attached to 2 different session(db)!
One of the reasons is that you may define your model with one db = SQLAlchemy(app) and add/insert/modify the database with another!
My solution is UNIFORMING THE DB!
try this:
u = db.session.query(User).filter(User.username == request.form["username"]).first()
Instead of this:
u = User.query.filter(User.username == request.form["username"]).first()
I had this problem too.
I created a test_file.py and added this code:
from app import app
from models import Tovar
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy(app)
tovardel = Tovar.query.filter(Tovar.region == 1 and Tovar.price == 12).first()
db.session.delete(tovardel)
tovar = Tovar.query.filter(Tovar.region == 1 and Tovar.price == 12).first()
print(tovar.description)
and when I ran the code I got this error:
Object '<Tovar at 0x7f09cbf74208>' is already attached to session '1' (this is '2')
PROBLEM SOLVING:
If you have db = SQLAlchemy(app) in, for example, text_file.py, and in app.py, you get this problem all time. You should del db = SQLAlchemy(app), and import db from app from app import db
I faced the same issue. I was defining models in a separate file and I had to call SQLAlchemy twice. That's why there were two different sessions were running.
I solved this by doing following:
In case you are trying to remove an object from db:
Just create the removeObject function inside the model
First of all, this is my first time working with sqlite and sqlalchemy, so I'm quite a noob. I've been encountering an IntegrityError: datatype mismatch when trying to import a row from a dataframe into a sqlite database using CRUD. This is the code I've been using.
import sqlite3
import csv
import pandas as pd
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine, MetaData, Table, Column, Integer, String, Enum, Float, ForeignKey
engine = create_engine('sqlite:///records.sqlite', echo = True)
meta = MetaData()
Base = declarative_base()
Session = sessionmaker(bind=engine)
session = Session()
df = pd.read_csv('records.csv')
class Records(Base):
__tablename__ = 'Records'
id = Column(Integer, primary_key = True)
description = Column(String)
userid = Column(Integer)
money = Column(Integer)
team = Column(Integer)
points = Column(Integer)
state = Column(String)
Base.metadata.create_all(engine)
row = Records(id = df['id'].iloc[0],
description = df['description'].iloc[0],
userid = df['userid'].iloc[0],
money = df['money'].iloc[0],
team = df['team'].iloc[0],
points = df['points'].iloc[0],
state = df['state'].iloc[0])
session.add(row)
session.commit()
It always ends with an IntegrityError: datatype mismatch. I've checked the type of the data by printing them out and I'm getting <class 'str'> for both 'description' and 'state, and <class 'numpy.int64'> for the rest, just as intended, so I'm not sure what the problem is here. Please advise, thank you.
I'm trying to use an SQLite database via SQLAlchemy 1.4 ORM to filter data based on relationships.
Data
My example data consists of groups and members in a simple many-to-many schema:
[...]
member_f = Member(name="F")
group_1 = Group(name="1", members=[member_a, member_b, member_c]) <-- find this group via member names
group_2 = Group(name="2", members=[member_a, member_b, member_f])
group_3 = Group(name="3", members=[member_a, member_c, member_d])
group_4 = Group(name="4", members=[member_d, member_e, member_f])
[...]
Full running example code (schema, objects, queries):
from sqlalchemy import Table, Column, Integer, String, ForeignKey
from sqlalchemy import create_engine, select, func, text, and_
from sqlalchemy.orm import relationship, declarative_base, sessionmaker
engine = create_engine("sqlite+pysqlite:///:memory:", future=True, echo=False)
Session = sessionmaker(bind=engine, future=True)
# Schema
Base = declarative_base()
groups_members = Table("groups_members", Base.metadata,
Column("group_id", ForeignKey("groups.id")),
Column("member_name", ForeignKey("members.name")),
)
class Group(Base):
__tablename__ = "groups"
id = Column(Integer, primary_key=True, autoincrement=True)
name = Column(String, nullable=False)
members = relationship("Member", secondary=groups_members, backref="groups", lazy="subquery")
def __repr__(self):
return f"<Group: {self.name}>"
class Member(Base):
__tablename__ = "members"
name = Column(String, primary_key=True)
def __repr__(self):
return f"<Member: {self.name}>"
Base.metadata.create_all(engine)
# Objects
member_a = Member(name="A")
member_b = Member(name="B")
member_c = Member(name="C")
member_d = Member(name="D")
member_e = Member(name="E")
member_f = Member(name="F")
group_1 = Group(name="1", members=[member_a, member_b, member_c])
group_2 = Group(name="2", members=[member_a, member_b, member_f])
group_3 = Group(name="3", members=[member_a, member_c, member_d])
group_4 = Group(name="4", members=[member_d, member_e, member_f])
print(f"{member_a}: {member_a.groups}") # OK
with Session() as session:
session.add(group_1)
session.add(group_2)
session.add(group_3)
session.add(group_4)
session.commit()
print(session.query(Group).all()) # OK
# Query users example
def get_members_in_more_than_2_groups():
with Session() as session:
return session.execute(
select(Member, func.count(groups_members.columns.group_id).label('group_members_count'))
.join(groups_members)
.group_by(Member.name)
.having(text('group_members_count > 2'))
).all()
for m in get_members_in_more_than_2_groups():
print(m) # OK
# Query groups problem: associated with A and B but not with E or F
def get_groups_by_member_names(member_names_included, member_names_excluded):
with Session() as session:
included = session.execute(select(Member).where(Member.name.in_(member_names_included))).all()
excluded = session.execute(select(Member).where(Member.name.in_(member_names_excluded))).all()
return session.execute(
select(Group)
.join(Group.members)
.where(
and_(
Group.members.contains(included),
~Group.members.contains(excluded),
)
)
.group_by(Group.id)
).scalars().all()
for g in get_groups_by_member_names(member_names_included=["A", "B"], member_names_excluded=["E", "F"]):
print(g) # Expected output: <Group: 1>
Goal
Now I'm trying to find all groups that
have both members with the names A and B (that's groups 1 and 2)
and don't have any member named E or F (removing group 2)
resulting in just group 1.
Problem
The relevant (and failing) function in the example code is get_groups_by_member_names and with my lack of database knowledge, I'm quite stuck.
Most existing questions that I could find on SO only need to filter by one relationship value. But I need them to consider the lists of included and excluded member names.
I have tried to get the members as SQLAlchemy objects first and inserting those into the query but without any luck. I may have done that completely wrong, though.
I also tried joining the tables, filtering with the names list and counting the grouped results... It's hard for me to tell whether I'm on the right track or not at all.
Running over all groups in Python and applying the filtering there would be my fallback workaround. But with many items, the database can probably handle it more efficiently.
Any help greatly appreciated, I am happy with anything that works. I could probably also work my way up from a functioning SQL statement.
Thanks for your time!
Edit 1:
I found this answer https://stackoverflow.com/a/21104689/5123171 and while it works on small data sets, it's terribly slow on larger ones (about 60 seconds for 500 members and 10k groups):
def get_group_by_members(member_names_included, member_names_excluded):
with Session() as session:
return session.query(Group).join(groups_members).filter(
groups_members.columns.member_name.in_(member_names_included)).group_by(Group.id).having(func.count(groups_members.columns.member_name) == len(member_names_included),
).filter(
~Group.members.any(Member.name.in_(member_names_excluded)),
).all()
Ok, here's what I ended up with via trial & error in an SQL editor. This is faster than the previous attempt (50 milliseconds on the same data).
The comments in the code correspond to the following steps:
Find groups containing excluded members
Filter those out of the assignment table
Filter remaining assignment table by included members
Group by group IDs
Return all remaining groups matching the number of included members
SQL
SELECT * FROM groups
WHERE id IN (
SELECT group_id FROM groups_members
WHERE member_name IN ("A", "B") // 3.
AND group_id NOT IN ( // 2
SELECT group_id FROM groups_members
WHERE member_name IN ("E", "F") // 1.
)
GROUP BY group_id // 4.
HAVING count(member_name) == 2 // 5.
)
SQLAlchemy
session.query(Group)
.where(Group.id.in_(
session.query(groups_members.c.group_id)
.where(
groups_members.c.member_name.in_(member_names_included), # 3.
groups_members.c.group_id.not_in( # 2.
session.query(groups_members.c.group_id).where(
groups_members.c.member_name.in_(member_names_excluded) # 1.
)
),
)
.group_by(groups_members.c.group_id) # 4.
.having(
func.count(groups_members.c.member_name)
== len(member_names_included) # 5.
))
)
.all()
And the full running example in one piece:
from sqlalchemy import Table, Column, Integer, String, ForeignKey
from sqlalchemy import create_engine, select, func, text, and_, not_
from sqlalchemy.orm import relationship, declarative_base, sessionmaker
engine = create_engine("sqlite+pysqlite:///:memory:", future=True, echo=False)
Session = sessionmaker(bind=engine, future=True)
# Schema
Base = declarative_base()
groups_members = Table(
"groups_members",
Base.metadata,
Column("group_id", ForeignKey("groups.id")),
Column("member_name", ForeignKey("members.name")),
)
class Group(Base):
__tablename__ = "groups"
id = Column(Integer, primary_key=True, autoincrement=True)
name = Column(String, nullable=False)
members = relationship(
"Member", secondary=groups_members, backref="groups", lazy="subquery"
)
def __repr__(self):
return f"<Group {self.id}: {self.name}>"
class Member(Base):
__tablename__ = "members"
name = Column(String, primary_key=True)
def __repr__(self):
return f"<Member: {self.name}>"
Base.metadata.create_all(engine)
# Objects
member_a = Member(name="A")
member_b = Member(name="B")
member_c = Member(name="C")
member_d = Member(name="D")
member_e = Member(name="E")
member_f = Member(name="F")
group_1 = Group(name="1", members=[member_a, member_b, member_c])
group_2 = Group(name="2", members=[member_a, member_b, member_f])
group_3 = Group(name="3", members=[member_a, member_c, member_d])
group_4 = Group(name="4", members=[member_d, member_e, member_f])
with Session() as session:
session.add(group_1)
session.add(group_2)
session.add(group_3)
session.add(group_4)
session.commit()
# Query
member_names_included = ["A", "B"]
member_names_excluded = ["E", "F"]
# Raw SQL variant
with Session() as session:
result = session.execute(
f"""
SELECT * FROM groups
WHERE id IN (
SELECT group_id FROM groups_members
WHERE member_name IN ("A", "B")
AND group_id NOT IN (
SELECT group_id FROM groups_members
WHERE member_name IN ("E", "F")
)
GROUP BY group_id
HAVING count(member_name) == 2
)
"""
).all()
groups = [Group(**r) for r in result]
for r in groups:
print(f'SQL {r}')
# ORM Variant
with Session() as session:
result = (
session.query(Group)
.where(
Group.id.in_(
session.query(groups_members.c.group_id)
.where(
# Matching any included members
groups_members.c.member_name.in_(member_names_included),
# Removing any groups containing excluded members
groups_members.c.group_id.not_in(
session.query(groups_members.c.group_id).where(
groups_members.c.member_name.in_(member_names_excluded)
)
),
)
# This is to make sure that all included members exist in a group, not just a few
.group_by(groups_members.c.group_id)
.having(
func.count(groups_members.c.member_name)
== len(member_names_included)
)
)
)
.all()
)
for r in result:
print(f'ORM {r}')
I hope this is helpful to anyone and if you have suggestions for improvement, please let me know.
I am reading from a bigquery table to generate a payload to upload to FB conversions api.
cols=["payload","client_user_agent","event_source_url"]
I am copying the column values directly from the bq table as I am unable to print the full output of the dataframe in note book.
payload="{"pageDetail":{"pageName":"Confirmation","pageContentType":"cart","pageSiteSection":"cart","breadcrumbs":[{"title":"Home","url":"/en/home.html"},{"title":"Cart","url":"/cart"},{"title":"Confirmation","url":"/order-confirmation="}],"pageCategory":"Home","pageCategory1":"Cart","pageCategory2":"Confirmation","proBtbGlobalHeader":false},"orderDetails":{"hceid":"3b94a","orderConfirmed":true,"orderDate":"2021-01-15","orderId":"0123","unique":2,"pricingSummary":{"total":54.01},"items":[{"productId":"0456","quantity":1,"shippingAddress":{"postalCode":"V4N 3X3"},"promotion":{"voucherCode":null},"clickToInstall":{"eligible":false}},{"productId":"0789","quantity":1,"fulfillment":{"fulfillmentCost":""},"shippingAddress":{"postalCode":"A4N 3Y3"},"promotion":{"voucherCode":null},"clickToInstall":{"eligible":false}}],"billingAddress":{"postalCode":"M$X1A7"}},"event":{"type":"Load","page":"Confirmation","timestamp":1610706772998,"language":"English","url":"https://www"}}"
client_user_agent="Mozilla/5.0"
event_source_url= "https://www.def.com="
I need the value for email=[orderDetails][hceid] and value=["orderDetails"]["pricingSummary"]["total"]
Initially all the payload I wanted was in a single column and I was able to achieve the uploads with the following code
import time
from facebook_business.adobjects.serverside.event import Event
from facebook_business.adobjects.serverside.event_request import EventRequest
from facebook_business.adobjects.serverside.user_data import UserData
from facebook_business.adobjects.serverside.custom_data import CustomData
from facebook_business.api import FacebookAdsApi
import pandas as pd
import json
FacebookAdsApi.init(access_token=access_token)
query='''SELECT JSON_EXTRACT(payload, '$') AS payload FROM `project.dataset.events` WHERE eventType = 'Page Load' AND pagename = "Confirmation" limit 1'''
df = pd.read_gbq(query, project_id= project, dialect='standard')
payload = df.to_dict(orient="records")
for i in payload:
#print(type(i["payload"]))
k = json.loads(i["payload"])
email = k["orderDetails"]["hcemuid"]
user_data = UserData(email)
value=k["orderDetails"]["pricingSummary"]["total"]
order_id = k["orderDetails"]["orderId"]
custom_data = CustomData(
currency='CAD',
value=value)
event = Event(
event_name='Purchase',
event_time=int(time.time()),
user_data=user_data,
custom_data=custom_data,
event_id = order_id,
data_processing_options= [])
events = [event]
#print(events)
event_request = EventRequest(
events=events,
test_event_code='TEST8609',
pixel_id=pixel_id)
#print(event_request)
a=event_request.execute()
print(a)
Now there are additional values client_user_agent that needs to be part of user data and event_source_url as parts of events in the above code that are present as two different columns in GBQ table.
I have tried similar code as above for multiple columns but I am receiving a
TypeError: Object of type Series is not JSON serializable
So I tried concatenating the columns and then create a json serializable object but I am not able to do an upload.
Below is where I am stuck and lost and not sure how to proceed further any inputs appreciated.
import time
from facebook_business.adobjects.serverside.event import Event
from facebook_business.adobjects.serverside.event_request import EventRequest
from facebook_business.adobjects.serverside.user_data import UserData
from facebook_business.adobjects.serverside.custom_data import CustomData
from facebook_business.api import FacebookAdsApi
import pandas as pd
import json
FacebookAdsApi.init(access_token=access_token)
query='''SELECT payload AS payload,location.userAgent as client_user_agent,location.referrer as event_source_url FROM `project.Dataset.events` WHERE eventType = 'Page Load' AND pagename = "Confirmation" limit 1'''
df = pd.read_gbq(query, project_id= project, dialect='standard')
df.reset_index(drop=True, inplace=True)
payload = df.to_dict(orient="records")
print(payload)
## cols = ['payload', 'client_user_agent', 'event_source_url']
## df['combined'] = df[cols].apply(lambda row: ','.join(row.values.astype(str)), axis=1)
## del df["payload"]
## del df["client"]
## del df["source"]
## payload = df.to_dict(orient="records")
#tried concatinating all columns in a the dataframe but not able to create a valid json object for upload
columns = ['payload', 'client_user_agent', 'event_source_url']
df['payload'] = df['payload'].str.replace(r'}"$', '')
payload = df[columns].to_dict(orient='records')
print(payload)
## df = df.drop(columns=columns)
## pd.options.display.max_rows = 4000
# #print(payload)
# for i in payload:
# print(i["payload"])
# k = json.loads(i["payload"])
# email = k["orderDetails"]["hcemuid"]
# print(email)
I am following the instructions from this page:https://developers.facebook.com/docs/marketing-api/conversions-api
I have used the bigquery json_extract_scalar function to extract data from nested column instead of pandas which is a relatively better solution for my scenario.
I have tried the solution mentioned in sqlalchemy create tables and also referred to flask documentation http://flask-sqlalchemy.pocoo.org/2.1/contexts/. I am facing problems creating the database tables using create_all(). Here is my code.
>>> from flask import Flask
>>> app = Flask('myflaskapp')
>>> from flask_sqlalchemy import SQLAlchemy
>>> app.url_map.strict_slashes = False
>>> app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql+psycopg2://my_dbuser:my_dbuser_password#localhost/my_dev_db'
>>> app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
>>> from myflaskapp.models import AdRequest, AdResult
>>> AdRequest.__table__
Table('ad_request', MetaData(bind=None), Column('id', Integer(), table=<ad_request>, primary_key=True, nullable=False), Column('status', String(length=10), table=<ad_request>, default=ColumnDefault('NEW')), Column('status_msg', String(length=100), table=<ad_request>, default=ColumnDefault('')), Column('query_str', String(length=100), table=<ad_request>), schema=None)
>>> db = SQLAlchemy(app)
>>> db.engine
Engine(postgresql+psycopg2://my_dbuser:***#localhost/my_dev_db)
>>> db.metadata.create_all(db.engine)
>>> db.engine
Engine(postgresql+psycopg2://my_dbuser:***#localhost/my_dev_db)
>>> db
<SQLAlchemy engine=postgresql+psycopg2://my_dbuser:***#localhost/my_dev_db>
>>> db.session.commit()
On the postgres console a "\dt" does not list the new table ad_request that should get created as a result of running create_all.
Furthermore, I added debug as follows app['SQLALCHEMY_ECHO']=True and I get the following output which I cannot decipher.
>>> app.config['SQLALCHEMY_ECHO']=True
>>> from models import *
>>> with app.app_context():
... db.create_all()
...
2017-07-17 10:24:09,766 INFO sqlalchemy.engine.base.Engine select relname from pg_class c join pg_namespace n on n.oid=c.relnamespace where pg_catalog.pg_table_is_visible(c.oid) and relname=%(name)s
2017-07-17 10:24:09,766 INFO sqlalchemy.engine.base.Engine {'name': 'ad_request'}
2017-07-17 10:24:09,768 INFO sqlalchemy.engine.base.Engine select relname from pg_class c join pg_namespace n on n.oid=c.relnamespace where pg_catalog.pg_table_is_visible(c.oid) and relname=%(name)s
2017-07-17 10:24:09,769 INFO sqlalchemy.engine.base.Engine {'name': 'ad_result'}
2017-07-17 10:24:09,772 INFO sqlalchemy.engine.base.Engine
CREATE TABLE ad_request (
id SERIAL NOT NULL,
status VARCHAR(10),
status_msg VARCHAR(100),
query_str VARCHAR(100),
PRIMARY KEY (id)
)
2017-07-17 10:24:09,772 INFO sqlalchemy.engine.base.Engine {}
2017-07-17 10:24:09,779 INFO sqlalchemy.engine.base.Engine COMMIT
2017-07-17 10:24:09,780 INFO sqlalchemy.engine.base.Engine
CREATE TABLE ad_result (
id SERIAL NOT NULL,
uuid_s VARCHAR(50),
score FLOAT,
ad_request_id INTEGER,
PRIMARY KEY (id),
FOREIGN KEY(ad_request_id) REFERENCES ad_request (id)
)
2017-07-17 10:24:09,780 INFO sqlalchemy.engine.base.Engine {}
2017-07-17 10:24:09,784 INFO sqlalchemy.engine.base.Engine COMMIT
I noticed that AdRequest.table shows Table('ad_request', MetaData(bind=None), ...
How can I make AdRequest bind to the db.metadata ?
Following is my models.py
# models.py
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
db = SQLAlchemy()
ma = Marshmallow()
class AdRequest(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
status = db.Column(db.String(10), default="NEW")
status_msg = db.Column(db.String(100), default="")
query_str = db.Column(db.String(100))
def __init__(self, query_str):
self.query_str = query_str
def __repr__(self):
return '<AdRequest %r, %r, %r, %r>' % (self.id, self.query_str, self.status, self.status_msg)
def as_dict(self):
return {'id': self.id,
'query_str': self.query_str,
'status': self.status,
'status_msg': self.status_msg,
}
class AdResult(db.Model):
id = db.Column(db.Integer, primary_key=True)
uuid_s = db.Column(db.String(50))
score = db.Column(db.Float)
ad_request_id = db.Column(db.Integer, db.ForeignKey('ad_request.id'))
def __init__(self, uuid_s, score, ad_request_id):
self.uuid_s = uuid_s
self.score = score
self.ad_request_id = ad_request_id
def __repr__(self):
return '<AdResult %r, %r, %s>' % (self.id, self.uuid_s, self.ad_request_id)
class AdRequestSchema(ma.Schema):
class Meta:
# Fields to expose
fields = ('id', 'status', 'status_msg', 'query_str')
Order matters when it comes to SQLAlchemy. You have to use the same SQLAlchemy instance when you declare your models and when you use them. In example you provided, you create your database twice - once in models file and once in Python console.
Just create a separate file called database.py with two lines:
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
Then in your models import it and use as base for your models:
from database import db
class AdRequest(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
# rest of your models file
And create your app with:
from flask import Flask
from database import db
from models import AdRequest, AdResult
app = Flask('myflaskapp')
app.url_map.strict_slashes = False
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///test.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
with app.app_context():
db.init_app(app) # this is important!
db.create_all()
Please let me know if it helped.
Edit: you can check if my code works by running it and checking out if test.db file was created. If the file is there but you still have your problem, maybe it is PostgreSQL specific issue.