I have an ObjectListView that displays information retrieved from an SQLite DB with SQLAlchemy.
def setupOLV(self):
self.loanResultsOlv.SetEmptyListMsg("No Loan Records Found")
self.loanResultsOlv.SetColumns([
ColumnDefn("Date Issued", "left", 100, "date_issued",
stringConverter="%d-%m-%y"),
ColumnDefn("Card Number", "left", 100, "card_id"),
ColumnDefn("Student Number", "left", 100, "person_id"),
ColumnDefn("Forename", "left", 150, "person_fname"),
ColumnDefn("Surname", "left", 150, "person_sname"),
ColumnDefn("Reason", "left", 150, "issue_reason"),
ColumnDefn("Date Due", "left", 100, "date_due",
stringConverter="%d-%m-%y"),
ColumnDefn("Date Returned", "left", 100, "date_returned",
stringConverter="%d-%m-%y")
])
I also have three models, Loan:
class Loan(DeclarativeBase):
"""
Loan model
"""
__tablename__ = "loans"
id = Column(Integer, primary_key=True)
card_id = Column(Unicode, ForeignKey("cards.id"))
person_id = Column(Unicode, ForeignKey("people.id"))
date_issued = Column(Date)
date_due = Column(Date)
date_returned = Column(Date)
issue_reason = Column(Unicode(50))
person = relation("Person", backref="loans", cascade_backrefs=False)
card = relation("Card", backref="loans", cascade_backrefs=False)
Person:
class Person(DeclarativeBase):
"""
Person model
"""
__tablename__ = "people"
id = Column(Unicode(50), primary_key=True)
fname = Column(Unicode(50))
sname = Column(Unicode(50))
and Card:
class Card(DeclarativeBase):
"""
Card model
"""
__tablename__ = "cards"
id = Column(Unicode(50), primary_key=True)
active = Column(Boolean)
I am trying to join the tables (loans and people) in order to retrieve and display the information in my ObjectListView. Here is my query method:
def getQueriedRecords(session, filterChoice, keyword):
"""
Searches the database based on the filter chosen and the keyword
given by the user
"""
qry = session.query(Loan)
if filterChoice == "person":
result = qry.join(Person).filter(Loan.person_id=='%s' % keyword).all()
elif filterChoice == "card":
result = qry.join(Person).filter(Loan.card_id=='%s' % keyword).all()
return result
I can retrieve and display every field stored in the loans table but forename and surname (should be drawn from people table and joined on person.id) are blank in my ObjectListView. I have SQL output on so I can see the query and it is not selecting at all from the people table.
How can I modify my query/ObjectListView to retrieve and display this information. ?
UPDATE: I have created an example script that is runnable here.
You're only querying for a Loan (qry = session.query(Loan)). Why do you expect something else to be in the results besides what's in the SELECT statement?
I admit that I am pretty new to SQLAlchemy myself, but I thought I would share what I use to display results from my queries. I have a program that uses a SQLite DB with 4+ tables and I pull data from 2-3 of them in a single query and display this information in an ObjectListView. I owe Mike Driscoll for his in depth tutorials, particularly wxPython and SqlAlchemy: An Intro to MVC and CRUD.
Here is what I would possibly add/change in your code.
In your model section add a "display" class such as:
def OlvDisplay(object):
def __init__(self, date_issued, card_id, person_id, fname, sname,
issue_reason, date_due, date_returned):
self.date_issued = date_issued
self.card_id = card_id
self.person_id = person_id
self.person_fname = fname
self.person_sname = sname
self.issue_reason = issue_reason
self.date_due = date_due
self.date_returned = date_returned
This display class is used in the convertResults definition below and assists with making sure the data is formatted properly for the ObjectListView.
The adjustment to your existing query function:
def getQueriedRecords(session, filterChoice, keyword):
"""
Searches the database based on the filter chosen and the keyword
given by the user
"""
qry = session.query(Loan)
if filterChoice == "person":
result = qry.join(Person).filter(Loan.person_id=='%s' % keyword).all()
elif filterChoice == "card":
result = qry.join(Person).filter(Loan.card_id=='%s' % keyword).all()
convertedResults = convertResults(result)
return convertedResults
What we're doing here is creating a local variable that is essentially running the conversion definition and storing the results for the next line, which returns those results.
And the "Convertor" function:
def convertResults(results):
finalResults = []
for record in results:
result = OlvDisplay(
record.date_issued,
record.card_id,
record.person_id,
record.person.fname,
record.person.sname,
record.issue_reason,
record.date_due,
record.date_returned
)
finalResults.append(result)
return finalResults
The important part here are the 2 lines:
record.person.fname
record.person.sname
Since we are wanting to pull information from another table using the established relationship it is important to refer to that relationship to actually see the data.
And to populate the ObjectListView Widget:
theOutput = getQueriedRecords(session, filterChoice, keyword)
self.setupOLV.SetObjects(theOutput)
Hope this helps you out.
-MikeS
Related
I have next data structure:
from enum import IntEnum, unique
from pathlib import Path
from datetime import datetime
from peewee import *
#unique
class Status(IntEnum):
CREATED = 0
FAIL = -1
SUCCESS = 1
db_path = Path(__file__).parent / "test.sqlite"
database = SqliteDatabase(db_path)
class BaseModel(Model):
class Meta:
database = database
class Unit(BaseModel):
name = TextField(unique=True)
some_field = TextField(null=True)
created_at = DateTimeField(default=datetime.now)
class Campaign(BaseModel):
id_ = AutoField()
created_at = DateTimeField(default=datetime.now)
class Task(BaseModel):
id_ = AutoField()
status = IntegerField(default=Status.CREATED)
unit = ForeignKeyField(Unit, backref="tasks")
campaign = ForeignKeyField(Campaign, backref="tasks")
Next code create units, campaign and tasks:
def fill_units(count):
units = []
with database.atomic():
for i in range(count):
units.append(Unit.create(name=f"unit{i}"))
return units
def init_campaign(count):
units = Unit.select().limit(count)
with database.atomic():
campaign = Campaign.create()
for unit in units:
Task.create(unit=unit, campaign=campaign)
return campaign
The problem appears when I'm trying to add more units into existing campaign. I need to select units which haven't been used in this campaign. In SQL I can do this using next query:
SELECT * FROM unit WHERE id NOT IN (SELECT unit_id FROM task WHERE campaign_id = 1) LIMIT 10
But how to do this using peewee?
The only way I've found yet is:
def get_new_units_for_campaign(campaign, count):
unit_names = [task.unit.name for task in campaign.tasks]
units = Unit.select().where(Unit.name.not_in(unit_names)).limit(count)
return units
It's somehow works but I'm 100% sure that it's the dumbest way to implement this. Could you show me the proper way to implement this?
Finally I found this:
Unit.select().where(Unit.id.not_in(campaign.tasks.select(Task.unit))).limit(10)
Which produces
SELECT "t1"."id", "t1"."name", "t1"."some_field", "t1"."created_at" FROM "unit" AS "t1" WHERE ("t1"."id" NOT IN (SELECT "t2"."unit_id" FROM "task" AS "t2" WHERE ("t2"."campaign_id" = 1))) LIMIT 10
Which matches with SQL query I've provided in my question.
P.S. I've done some research and it seems to be a proper implementation, but I'd appreciate if somebody correct me and show the better way (if exist).
This code only creates one record. What is wrong?
class PartnerTagCreate(models.TransientModel):
""" Choose tags to be added to partner."""
_name = 'partner.tags.create'
_description = __doc__
market_id = fields.Many2one('partner.tags', string='Market Tag')
application_id = fields.Many2one('partner.tags', string='Application Tag')
partner_id = fields.Integer()
#api.multi
def create_contact_tag(self):
for record in self.env['sale.order.line'].browse(self._context.get('active_ids', [])):
vals = {}
vals['partner_id'] = record.order_partner_id
self.write(vals)
return True
I need this function to create one record for each order_partner_id I selected before opening the wizard...
How to achieve that?
Here my new code (function) ...
def create_contact_tag(self):
sale_order_line_ids = self.env['sale.order.line'].browse(self._context.get('active_ids', []))
for partner in sale_order_line_ids:
values = {}
values['partner_id'] = partner.order_partner_id
self.create(values)
return {}
This creates one record for marketing_id and/or application_id and dedicated records for each partner_id in the record.
You use the 'create' method to create new records; this is the same for TransientModel as for the persistent Model.
So, replace
self.write(vals)
by
self.create(vals)
and you should be fine.
Entities:
class Car(db.Entity):
image = Set("Image")
name = Required(str, 40,)
class Image(db.Entity):
name = Required(str, unique=True)
car = Required(Car)
And I want to get information on cars-list page: one car - one image of that car.
I use:
cars = select((car, car.image) for car in Car).distinct().show()
I have
Car[1]|Image[1]
Car[1]|Image[2]
...
Car[5]Image[1]
Car[5]Image[2]
...
But I need only first image of each car, not all images.
How to do this?
Thanks!
Code to get only first image for each car (image with lowest id):
#!/usr/bin/env python
from pony.orm import *
db = Database()
db.bind('sqlite', ':memory:', create_db=True)
class Car(db.Entity):
image = Set("Image", lazy=True)
name = Required(str, 40)
class Image(db.Entity):
name = Required(str, unique=True)
car = Required(Car)
db.generate_mapping(create_tables=True)
sql_debug(True)
with db_session:
car1 = Car(name='car1')
car2 = Car(name='car2')
image1 = Image(name='image1', car = car1)
image2 = Image(name='image2', car = car1)
image3 = Image(name='image3', car = car2)
cars = select((car, car.name, image, image.name) for car in Car for image in car.image if image.id == min(car.image.id)).show()
Result:
GET CONNECTION FROM THE LOCAL POOL
SWITCH TO AUTOCOMMIT MODE
BEGIN IMMEDIATE TRANSACTION
INSERT INTO "Car" ("name") VALUES (?)
[u'car1']
INSERT INTO "Car" ("name") VALUES (?)
[u'car2']
INSERT INTO "Image" ("name", "car") VALUES (?, ?)
[u'image1', 1]
INSERT INTO "Image" ("name", "car") VALUES (?, ?)
[u'image2', 1]
INSERT INTO "Image" ("name", "car") VALUES (?, ?)
[u'image3', 2]
SELECT "car"."id", "car"."name", "image"."id", "image"."name"
FROM "Car" "car"
LEFT JOIN "Image" "image-1"
ON "car"."id" = "image-1"."car"
LEFT JOIN "Image" "image"
ON "car"."id" = "image"."car"
GROUP BY "car"."id", "car"."name", "image"."id", "image"."name"
HAVING "image"."id" = MIN("image-1"."id")
car |car.name|image |image.name
------+--------+--------+----------
Car[1]|car1 |Image[1]|image1
Car[2]|car2 |Image[3]|image3
COMMIT
RELEASE CONNECTION
By the way, the generated sql is rather strange, I don't think that executing two identical left joins makes any sense.
Edit: OK, it makes sense (see comments).
I have a legacy Google App engine code, which is having the following entity classes in Python
class AffiliateParent(db.Model):
name = db.StringProperty(required = True)
class Affiliate(db.Model):
email = db.StringProperty(required = True)
point_gain = db.IntegerProperty()
point_used = db.IntegerProperty()
#feature_upgrade = db.ListProperty(str)
modified_time = db.DateTimeProperty(auto_now = True)
I was wondering, is the following the correct way to generate unique id? Are they guarantee unique within Affiliate table?
affiliate_parent_key = AffiliateParent.all(keys_only=True).filter('name =', 'yancheng').get();
affiliate_parent = db.get(affiliate_parent_key);
# check whether affiliate exist, if not create one
affiliate_parent = db.get(affiliate_parent_key);
q = Affiliate.all()
q.ancestor(affiliate_parent)
q.filter('email =', email)
affiliate = q.get()
if not affiliate:
affiliate = Affiliate(
email = email,
point_gain = 0,
point_used = 0,
parent = affiliate_parent
)
affiliate.put()
# 4503602445942784
# is this unique?
unique_id = affiliate.key().id()
yes, if you don't supply id or key when instantiating the model, then datastore will generate a unique ID and assign it to your entity when you .put() it... thus affiliate.key.id() will be unique
you can also generate unique IDs using allocate_ids(count)
https://cloud.google.com/appengine/docs/python/datastore/functions#allocate_ids
I am trying to create a program that loads in over 100 tables from a database so that I can change all appearances of a user's user id.
Rather than map all of the tables individually, I decided to use a loop to map each of the tables using an array of objects. This way, the table definitions can be stored in a config file and later updated.
Here is my code so far:
def init_model(engine):
"""Call me before using any of the tables or classes in the model"""
meta.Session.configure(bind=engine)
meta.engine = engine
class Table:
tableID = ''
primaryKey = ''
pkType = sa.types.String()
class mappedClass(object):
pass
WIW_TBL = Table()
LOCATIONS_TBL = Table()
WIW_TBL.tableID = "wiw_tbl"
WIW_TBL.primaryKey = "PORTAL_USERID"
WIW_TBL.pkType = sa.types.String()
LOCATIONS_TBL.tableID = "locations_tbl"
LOCATIONS_TBL.primaryKey = "LOCATION_CODE"
LOCATIONS_TBL.pkType = sa.types.Integer()
tableList = ([WIW_TBL, LOCATIONS_TBL])
for i in tableList:
i.tableID = sa.Table(i.tableID.upper(), meta.metadata,
sa.Column(i.primaryKey, i.pkType, primary_key=True),
autoload=True,
autoload_with=engine)
orm.mapper(i.mappedClass, i.tableID)
The error that this code returns is:
sqlalchemy.exc.ArgumentError: Class '<class 'changeofname.model.mappedClass'>' already has a primary mapper defined. Use non_primary=True to create a non primary Mapper. clear_mappers() will remove *all* current mappers from all classes.
I cant use clear_mappers as it wipes all of the classes and the entity_name scheme doesn't seem to apply here.
It seems that every object wants to use the same class, although they all should have their own instance of it.
Does anyone have any ideas?
Well, in your case it *is the same Class you try to map to different Tables. To solve this, create a class dynamically for each Table:
class Table(object):
tableID = ''
primaryKey = ''
pkType = sa.types.String()
def __init__(self):
self.mappedClass = type('TempClass', (object,), {})
But I would prefer slightly cleaner version:
class Table2(object):
def __init__(self, table_id, pk_name, pk_type):
self.tableID = table_id
self.primaryKey = pk_name
self.pkType = pk_type
self.mappedClass = type('Class_' + self.tableID, (object,), {})
# ...
WIW_TBL = Table2("wiw_tbl", "PORTAL_USERID", sa.types.String())
LOCATIONS_TBL = Table2("locations_tbl", "LOCATION_CODE", sa.types.Integer())