I am not able to iterate through my query as I would like using Peewee
Those are the related Objects in Models.py
class Conversation(peewee.Model):
id = peewee.AutoField(unique=True, index=True)
creation_date = peewee.DateTimeField(default=datetime.now)
contact_id = ForeignKeyField(Contact, backref='conversation')
launch_id = ForeignKeyField(Launch, backref='conversation')
request_data = peewee.TextField(null=True)
status = peewee.TextField(null=True)
class Contact(peewee.Model):
id = peewee.AutoField(unique=True, index=True)
uuid = peewee.CharField(default=shortuuid.uuid, index=True)
whatsapp_phone = peewee.CharField(index=True, default='')
status = peewee.CharField(default='init')
conversationId = peewee.CharField(null=True)
Here's how I am trying to iterate:
for conversation in Conversation.select().where(Conversation.launch_id == str(launch_id)):
print(conversation.contact.id)
And this is the error that I a getting:
print(conversation.contact.id)
AttributeError: 'Conversation' object has no attribute 'contact'
I've tried to change the way I do my query:
query = Conversation.select(Contact).join(Contact).where(Conversation.launch_id == str(launch_id))
But I get the exact same error if I iterate in the same way.
The issue is you are, for some reason, trying to access .contact when you've named your foreign-key .contact_id. The peewee docs are clear about foreign key naming, but you want this:
class Conversation(peewee.Model):
id = peewee.AutoField(unique=True, index=True)
creation_date = peewee.DateTimeField(default=datetime.now)
# Data will be stored in a column named "contact_id":
contact = ForeignKeyField(Contact, backref='conversations')
# Data will be stored in a column named "launch_id":
launch = ForeignKeyField(Launch, backref='conversations')
request_data = peewee.TextField(null=True)
status = peewee.TextField(null=True)
This allows:
query = (Conversation
.select()
.where(Conversation.launch == str(launch_id)))
for conversation in query:
# Access the underlying foreign-key value.
print(conversation.contact_id)
Or, if you intend to access other fields on the Contact:
query = (Conversation
.select(Conversation, Contact)
.join(Contact)
.where(Conversation.launch == str(launch_id)))
for conversation in query:
# We now have a "full" Contact instance we can access efficiently:
print(conversation.contact.id)
Please read the docs:
http://docs.peewee-orm.com/en/latest/peewee/quickstart.html#lists-of-records
http://docs.peewee-orm.com/en/latest/peewee/relationships.html
http://docs.peewee-orm.com/en/latest/peewee/models.html#foreignkeyfield
Related
Very simple trying to run a query in Python 3 sqlalchemy to delete some records given string names of table and field to query against.
How do you get the table object from a string?
Given 1. how do you run a query via ORM with just a string of the field name?
I would assume all ORM's have an internal array or method like get with the name.
json_config = [
{"table": "tableA",
"field": "modified_on"
"expires": 30},
{"table": "tableB",
"field": "event_on"
"expires": 30}
]
for table_conf_item in self.json_config:
table_name = table_conf_item["table"]
field_name = table_conf_item["field"]
expire_after = table_conf_item["expires"]
table_obj = self.orm_session.TABLES[table_name]
field_obj = self.orm_session.TABLES[table_name].FIELDS[field_name]
result = self.orm_session.delete(table_obj).where(field_obj < expire_after)
self.orm_session.commit()
print(f"{table_name}: removed {result.row_count} objects")
Given the table's name, you can use reflection to get a Table object. Using SQLAlchemy's core layer, this is reasonably straightforward:
import sqlalchemy as sa
engine = sa.create_engine(...)
tbl = sa.Table(name_of_table, metadata, autoload_with=engine)
If you want to work with multiple tables, it may be more efficient to store them a Metadata instance for later access:
metadata = sa.MetaData()
metadata.reflect(engine, only=list_of_table_names)
tbl = metadata.tables[name_of_table]
Once you have a Table object you can reference columns by name like this: tbl.c[name_of_field].
Full example:
import sqlalchemy as sa
# Setup
engine = sa.create_engine('sqlite://', echo=True, future=True)
tbl = sa.Table(
't',
sa.MetaData(),
sa.Column('id', sa.Integer, primary_key=True),
sa.Column('foo', sa.Integer),
)
tbl.create(engine)
with engine.begin() as conn:
vals = [42, 43, 42, 43, 56, 87, 89]
conn.execute(tbl.insert(), [{'foo': v} for v in vals])
del tbl
# Reflect the table.
metadata = sa.MetaData()
metadata.reflect(engine, only=['t'])
tbl = metadata.tables['t']
# Define some statements.
q1 = sa.select(tbl).where(tbl.c['foo'] == 42)
q2 = sa.select(tbl.c['id'], tbl.c['foo']).where(tbl.c['foo'] == 43)
q3 = sa.delete(tbl).where(tbl.c['foo'] != 42)
# Execute the statements.
with engine.connect() as conn:
rows = conn.execute(q1)
for row in rows:
print(row)
print()
rows = conn.execute(q2)
for row in rows:
print(row)
print()
with engine.begin() as conn:
conn.execute(q3)
with engine.connect() as conn:
rows = conn.execute(q1)
for row in rows:
print(row)
print()
Doing the same through the ORM layer is more complicated, as table and column names must be mapped to ORM entity classes (models) and their attributes. This replicates the previous example for a simple mapping (it assumes the same initial data as above).
import sqlalchemy as sa
from sqlalchemy import orm
Base = orm.declarative_base()
class Thing(Base):
__tablename__ = 't'
id = sa.Column(sa.Integer, primary_key=True)
thing_foo = sa.Column('foo', sa.Integer)
engine = sa.create_engine(...)
Base.metadata.create_all(engine)
Session = orm.sessionmaker(engine, future=True)
tablename = 't'
columnname = 'foo'
with Session.begin() as s:
# Get the mappers for the Base class.
mappers = Base.registry.mappers
# Get the mapper for our table.
mapper = next(m for m in mappers if m.entity.__tablename__ == tablename)
# Get the entity class (Thing).
entity = mapper.entity
# Get the column from the Table.
table_column = mapper.selectable.c[columnname]
# Get the mapper property that corresponds to the column
# (the entity attribute may have a different name to the
# column in the database).
mapper_property = mapper.get_property_by_column(table_column)
# Get the queryable entity attribute (Thing.thing_foo).
attr = mapper.all_orm_descriptors[mapper_property.key]
q = sa.select(entity).where(attr != 42)
entities = s.scalars(q)
for entity in entities:
s.delete(entity)
with Session() as s:
for thing in s.scalars(sa.select(Thing)):
print(thing.id, thing.thing_foo)
I'm trying to understand why I'm getting sql errors for the following objects.
I'm using a PostGresSql database on heroku
class Member(BASE):
__tablename__ = "members"
name = Column(String)
discord_id = Column(BigInteger, primary_key=True,nullable=False)
role = Column(String, ForeignKey('roles.name'))
nick = Column(String)
rs_runs = relationship("RSRun",secondary='member_on_rs_run')
def __init__(self,name,discord_id,nick="" ):
self.name = name
self.discord_id = discord_id
self.nick = nick
class RSRun(BASE):
__tablename__ = "rs_runs"
id = Column(Integer, primary_key=True, nullable=False)
level = Column(String)
dtg = Column(DateTime)
members = relationship("Member",secondary='member_on_rs_run')
class MemberOnRSRun(BASE):
__tablename__ = "member_on_rs_run"
member_id = Column(BigInteger, ForeignKey('members.discord_id'),primary_key = True)
run_id = Column(Integer,ForeignKey('rs_runs.id'),primary_key=True)
The errors I'm getting are here
sqlalchemy.exc.DataError: (psycopg2.errors.NumericValueOutOfRange) integer out of range
[SQL: INSERT INTO members (name, discord_id, role, nick) VALUES (%(name)s, %(discord_id)s, %(role)s, %(nick)s)]
[parameters: {'name': '', 'discord_id': 126793648221192192, 'role': None, 'nick': ''}]
I've checked and the discord_id is within legal range of a PostGres BigInt which is what I'm assuming I'm getting with an sqlalchemy Biginteger Column. But it keeps telling me it's out of range for integer. Obviously I want to use the same ID that Discord is using since that is the identifier for a member on Discord.
Making changes to the python objects that you are using in the sqlalchemy declarative form will not FORCE heroku to update the database. You must manually blow away the database for these changes to take affect.
I'm looking to use Flask-SQLAlchemy Bind to connect to a secondary Oracle database. I'm getting an error that says the table I want to connect to is not defined although it is defined in my model with the appropriate bind configuration added. Here is the specific error: NameError: name 'ACCOUNT' is not defined . This error happens before any attempt to actually query the database.
What am I missing?
I've browsed various examples via Google and StackOverflow and compared them with my code, but I do not see anything out of the ordinary with setup.
Here are the relevant bits of code... mysql queries work, oracle queries do not.
init.py
from flask_sqlalchemy import SQLAlchemy
database_url = "mysql+pymysql://root:xxxx#localhost:3306/db1"
dbbind_url = "oracle://dbuser:xxxx#10.0.0.1:1521/db2"
app.config["SQLALCHEMY_DATABASE_URI"] = database_url
app.config["SQLALCHEMY_BINDS"] = {
'oracle': dbbind_url
}
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
db = SQLAlchemy(app)
models.py
## Mysql Model (working)
class CUSTOMERS (db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(255))
## Oracle Model (not working)
class ACCOUNT(db.Model):
__tablename__ = 'ACCOUNT'
__bind_key__ = 'oracle'
account_id = db.Column(db.Integer, unique=True, nullable=False, primary_key=True)
account = db.Column(db.String(400), nullable=False)
views.py
#app.route('/helper', methods=['GET','POST'])
def helper_search():
form = HelperSearchForm()
if form.validate_on_submit():
accountquery = form.account.data
print (accountquery)
accountInfo = ACCOUNT.query.filter_by(ACCOUNT=accountquery).first()
return redirect(url_for('helper_accountdetail',account=accountInfo))
"CUSTOMERS" Table Structure (MYSQL)
id INT 11
name VARCHAR 255
"ACCOUNT" Table Structure (Oracle)
ACCOUNT_ID NUMBER(11,0)
ACCOUNT VARCHAR2(400 BYTE)
The current result is:
NameError: name 'ACCOUNT' is not defined
The expected result is:
The query is returned with a result.
I'm new in SQLalchemy I need to calculate multiple of some price in my one of the table. This is my tables:
class Order(DeclarativeBase):
__tablename__ = 'order'
id = Field(Integer, primary_key=True)
products = relationship("OrderProduct", back_populates="order", lazy='dynamic')
and
class OrderProduct(DeclarativeBase):
__tablename__ = 'order_products'
id = Field(Integer, primary_key=True)
order_id = Column(Integer, ForeignKey('order.id'), nullable=False)
order = relationship("Order", back_populates="products", protected=True)
product_id = Column(Integer, ForeignKey('product.id'), nullable=False)
product = relationship("Product", back_populates="order_product")
quantity = Field(Integer, nullable=False)
and
class Product(DeclarativeBase):
__tablename__ = 'product'
id = Field(Integer, primary_key=True)
price = Field(Integer)
order_product = relationship("OrderProduct", back_populates="product", protected=True)
I want to multiple price with this situation OrderProduct.quantity * Product.price and products in Order table is an array of Products
I write SQL query like this and it works:
SELECT SUM(price*quantity) FROM product
JOIN order_products ON product.id = order_products.product_id
JOIN order ON order_products.order_id = order.id;
I tried to make it in ORM like this but it takes me Product and I can calculate only price without multiple in quantity:
result = 0
for product in Product.query\
.join(OrderProduct).filter(Product.id == OrderProduct.product_id)\
.join(Order).filter(OrderProduct.order_id == self.id):
result = product.price + result
return result
I make this as #hybrid_property and its work well.
I use a framework that name is restfulpy. it has ORM for sqlalchemy, session in this framework is scoped_session, but it gives me SQL query in debuging mode instead of executing the query like this :
sum_price = {Query}SELECT sum(product.price * order_products.quantity) AS sum_1
FROM product JOIN order_products ON product.id = order_products.product_id JOIN "order" ON "order".id = order_products.order_id
WHERE product.id = order_products.product_id AND order_products.order_id = :order_id_1
Well, Can anyone help me out this problem?
with regards
I just realized that SQLalchemy is a great ORM! When you have a relation between two, three or ... tables, SQLalchemy make a join between them and you just query it!
I made it hard for me and my friends :) SQLalchemy is powerful than what I'm thinking!
This is the right answer:
#hybrid_property
def total_price(self):
return DBSession.query(
func.sum(Product.price * OrderProduct.quantity))\
.filter(OrderProduct.product_id == Product.id) \
.filter(OrderProduct.order_id == self.id).scalar()
DBSession is the same with session
from sqlalchemy import func
query = session.query(func.sum(Product.price*OrderProduct.quantity))
.join(OrderProduct).filter(Product.id == OrderProduct.product_id)
.join(Order).filter(OrderProduct.order_id == self.id)
Trying to join the tables below using this command:
Subscription.query.filter( return Subscription.query.filter(Subscription.watch_id == id).join(User).filter_by(watch_id=id)
I get this error:
sqlalchemy.exc.InvalidRequestError: Could not find a FROM clause to join from. Tried joining to <class 'app.user.model.User'>, but got: Can't find any foreign key relationships between 'wm_subscription' and 'user'.
Essentially my end goal is to get a query that gets a List of Users that share a watch_id. Not sure if the models or the query is correct. Anybody know what's wrong?
Database = declarative_base(cls=DbBase)
class Subscription(Database):
__tablename__ = 'wm_subscription'
subscription_id = UniqueIdPk()
watch_id = UniqueIdRefNotNull(index=True)
user_id = UniqueIdRefNotNull(ForeignKey('User.user_id'), index=True)
subscription_watch = relationship('Watch',
primaryjoin='Subscription.watch_id == Watch.watch_id',
foreign_keys='Watch.watch_id',
uselist=True)
subscription_user = relationship('User',
primaryjoin='Subscription.watch_id == User.user_id',
foreign_keys='User.user_id',
uselist=True,
backref='user')
class User(Database, UserMixin):
__tablename__ = 'user'
user_id = UniqueIdPk()
# Google sub ID - unique to user https://developers.google.com/identity/protocols/OpenIDConnect
google_id = Column(String(length=50))
# override email mixin for unique index
email = Email(unique=True)
first_name = Name()
last_name = Name()
def get_id(self):
return self.user_id
This is the correct query:
Subscription.query.filter(Subscription.watch_id == id).join(User)