Tagged Questions
0
votes
1answer
9 views
SQLAlchemy type containing strings larger than 4000 on Oracle using Varchar2
I am using Oracle database and in a certain column I need to insert Strings, which in some cases are larger than 4000 symbols (Oracle 11g limits Varchar2 size to 4000). We are required to use Oracle ...
0
votes
0answers
23 views
Long chained exists query with multiple one-to-many mappings in the chain
Edit: Following piece seems to be the right way:
session.query(User).join("userGadgets", "gadget", "components","gadgetComponentMetals")
Original:
I have the following tables configured:
class ...
1
vote
1answer
31 views
How can I rank entries using sqlalchemy?
I have created a model User that has the columns score and rank. I would like to periodically update the rank of all users in User such that the user with the highest score has rank 1, second highest ...
0
votes
1answer
16 views
Insert and update with core SQLAlchemy
I have a database that I don't have metadata or orm classes for (the database already exists).
I managed to get the select stuff working by:
from sqlalchemy.sql.expression import ColumnClause
from ...
0
votes
1answer
19 views
SQLAlchemy, Flask: get relationships from a db.Model
I need to get a list of a model's properties which are actually relationships (that is, they were created by relationship()).
Say I have a model Foo in a models:
class Thing(db.Model):
id = ...
0
votes
1answer
17 views
Exception Handler Not Working: Commiting to SQL Database with SQLAlchemy in Python
I am trying to commit entries to a MySQL database using SQLAlchemy in Python. The function below was meant to allow me to commit a batch of entries, even if one or two of them contained errors that ...
0
votes
1answer
21 views
sqlalchemy.orm.exc.UnmappedInstanceError in flask
I have been reading the SQLAlchemy docs, but I don't understand them. The error (UnmappedInstanceError) says something isn't mapped. What isn't mapped? I really don't get sqlalchemy and I want to go ...
1
vote
1answer
37 views
SQLAlchemy insert, update precondition (consistency check)
I would like to keep an invariant when inserting into or updating an 'interval' many-to-many relation using SQLAlchemy.
The goal is to make sure that there are no overlapping intervals in the table ...
0
votes
1answer
27 views
Multiple databases in Pyramid
Firstly, I'm new to Python.
Now that that's out of the way. I'm trying to access data on 2 different databases and display information on one view.
...
0
votes
2answers
20 views
Remove objects from sqlalchemy session
I have a portion of the code which does the following:
get the data from the database
perform an API call to one server
perform another API call to another server
store the results in the database ...
0
votes
1answer
16 views
SQLAlchemy: Effect of 2 session objects?
Will the following use 2 DB connections from the connection pool because of the useage of 2 session calls?
users_from_contacts = db.session.query(User).join(Email, Email.user_id == ...
0
votes
1answer
17 views
Sqlalchemy relationship to built-in type
I have something similar to this:
class Item(Base, DBBase):
__tablename__ = 'item'
id = Column(Integer, primary_key = True)
name = Column(String), nullable = True)
comments = ...
0
votes
1answer
27 views
SQLALchemy custom integer sort order
I have a table with a column of integers that represent the type of the row. These integers range from 1 - 5. How do I specify a custom sort order in SQLAlchemy, for example if I want the rows sorted ...
2
votes
1answer
29 views
Error in SQLAlchemy with Integer: “object() takes no parameters”
I suddenly started seeing an error in my Python SQLAlchemy application and I can't figure out what's causing it. My code looks like this:
from sqlalchemy import create_engine
from sqlalchemy import ...
0
votes
0answers
20 views
SQLAlchemy load_only and defer
I have tried using the SQLAlchemy methods load_only and defer to send only certain columns from the database, but I can't seem to get them to work.
Here is the code I am using:
query = ...
0
votes
1answer
25 views
how to insert a dictionary with sqlsoup
I am trying to insert a dictionary with sqlsoup. Unfortuntely this doesn't work:
db.blah_table.insert({"blah_field" : "blah_value"})
it gives me an error
TypeError: insert() takes exactly 1 ...
0
votes
0answers
17 views
SQLAlchemy problems when using very long connection string
I'm using a connection-string/DSN with a really long hostname. SA seems to not like it. I've sanitized the error/trace, below.
Debugging is made difficult by the fact that this error is raised within ...
1
vote
1answer
35 views
Converting string to date timestamp in SQLAlchemy
I have a database table, which I am accessing through SQLAlchemy. Each row is timestamped, but unfortunately it isn't simply a column with a DATE type.
It is timestamped with two columns. One is the ...
0
votes
1answer
18 views
Select partial entities with specific columns
In SqlAlchemy, I need to fetch partial entities with the given list of fields.
Other answers suggest to do any of the following:
session.query(User.id, User.login).all()
...
0
votes
0answers
35 views
Safe relational query language for public use via the API
I'm developing an API which, among other features, provides CRUD access to the PostgreSQL storage. I need to expose some SQL features such as:
Projection (pick/omit fields in the result set)
...
3
votes
2answers
31 views
Query to check if size of collection is 0 or empty in SQLAlchemy?
Person has one Building.
Person has many Group
I want to return all of the people from a certain building who do not have any Group in their groups collection. Maybe I can search by people who have ...
0
votes
0answers
20 views
How to append a FromClause to a Select by joining on SQLAlchemy
I'm constructing accumulative selects. For example:
from sqlalchemy import sql
query1 = sql.select(
[table1, table2],
from_obj=table1.join(table2, table1.c.id == table2.c.fk))
# Do things ...
0
votes
1answer
26 views
Delayed change using sqlalchemy
I'm facing a strange behaviour in multi-process environment.
My first process (later called P1) writes to db through sqa. My second process (later called P2) reads from db through sqa. This second ...
1
vote
0answers
21 views
Alembic support for multiple Postgres schemas
How can I use Alembic's --autogenerate to migrate multiple Postgres schemas that are not hard-coded in the SQL Alchemy model? (mirror question of SQLAlchemy support of Postgres Schemas, but for ...
0
votes
0answers
19 views
Separate session objects for separate REST requests in SqlAlchemy?
I am using sqlalchemy (with MySQL as database) with cherrypy. I have created an engine which is application-wide. I read from SqlAlchemy Sessions Doc that sessions are not thread-safe. Does that mean ...
0
votes
0answers
33 views
Storing UTC timestamps in Postgresql to later be displayed with AngularJS
I have read quite a bit on storing timestamps in UTC and keeping the timestamps in UTC until the last possible moment (i.e. when it is displayed to the user in the browser).
However, I am still a ...
1
vote
1answer
84 views
Sqlalchemy sometimes can not get data
I have a database named weixin_db and there is a table named nvi_instance in it. This is detail :
mysql> desc instance;
+--------------+------------------+------+-----+---------+----------------+
...
1
vote
1answer
21 views
Dynamically query a subset of columns in sqlalchemy
Assume only two columns(name and id) are needed from a table. I would code something like below:
session.query(User.id, User.name).all()
But if the column names are dynamic,
def get_data(table, ...
0
votes
1answer
16 views
how verify if sqlalchemy session is configured?
standard/normal configuration of sqlalchemy session:
from sqlalchemy.orm import scoped_session, sessionmaker
DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension())) # 0
...
0
votes
1answer
26 views
Adding an object to a one-to-many relationship in Pyramid, SQLAlchemy
I have set up a simple system for adding comments to items in my database using a one-to-many relation (one item can have many comments), but I can't seem to get it to work. It should be simple, I ...
1
vote
1answer
30 views
Prevent touching db during unit testing with SQLAlchemy
I've been using Django for several years, but have recently decided to try out Flask for a new API. Thanks to Carl Meyers excellent presentation on testing Django at PyCon, I've been using the ...
0
votes
1answer
50 views
SQLAlchemy - 'Table' object has no attribute 'datetime'
I'm getting the following error on the code below. I'm not seeing the point where table/object is returned, or at least should be. Any other pointers would be welcome too.
I run
...
1
vote
1answer
13 views
Why is my scoped_session raising an AttributeError: 'Session' object has no attribute 'remove'
I'm trying to set up a system that elegantly defers database operations to a seperate thread in order to avoid blocking during Twisted callbacks.
So far, here is my approach:
from contextlib import ...
0
votes
0answers
15 views
why sqlalchemy model instance doesn't update after updated instance '__dict__' and committed
I am using sqlalchemy and update model instance __dict__ to for update record, bud doesn't work
#user is a model instance queried from database
vars(user).update(**update_dict)
...
3
votes
0answers
34 views
Is this an acceptable way to make threaded SQLAlchemy queries from Twisted?
I've been doing some reading on using SQLAlchemy's ORM in the context of a Twisted application. It's a lot of information to digest, so I'm having a bit of trouble putting all the pieces together. ...
1
vote
1answer
9 views
How to set client_flags of FOUND_ROWS in SQLAlchemy with mysqlconnector to return affected rows
I am trying to change the behavior of ResultProxy.rowcount attribute for SQLAlchemy.
The configuration is mysql+mysqlconnector.
I am setting connect_args = {'client_flags': [ClientFlag.FOUND_ROWS]} in ...
3
votes
0answers
35 views
SQLAlchemy get value from a table if not present in another one
i'm trying to do the following:
class Property(Base):
name = Column(String(50))
default_value = Column(String(50))
class AssociatedProperty(Base):
property_id = Column(Integer, ...
1
vote
0answers
27 views
How can I compare SQLAlchemy UTC dates in the user's timezone?
I'm trying to fetch events to display on a calendar in the user's local time. All dates are stored in Postgres as UTC.
Here's the Event model and the query in question,
from datetime import ...
0
votes
1answer
22 views
Why can't I run a query against my has many relationship in SQLAlchemy?
I have a table called Group which has many Person through groups_people. This is that part of the Group table:
class Group:
...
...
people = db.relationship('Person', secondary=groups_people,
...
1
vote
1answer
21 views
Alembic --autogenerate fails for me
The command I'm running:
alembic -c development.ini revision --autogenerate -m "test"
I get the following result:
Traceback (most recent call last):
File ...
1
vote
0answers
28 views
SQLAlchemy get SQL INSERT statement
Is any way to get INSERT/UPDATE statement before commiting?
I mean if I create object
order = Order(qty=1, comment='ccc')
session.add(order)
I'd like to get
INSERT INTO "Orders" ("qty", ...
0
votes
1answer
24 views
Using a separate PasteDeploy file for sqlAlchemy urls with cryptic passwords
I have a Pyramid application I am working on. I, ideally, need the ability to put the sqlalchemy url settings into a separate file, and then consume this file on the engine_from_config file. By ...
0
votes
0answers
19 views
Lists from columns from SQLalchemy ResultProxy object
I execute a query like this:
query_result = engine.execute(SQLQUERY)
and the result is a ResultProxy object.
I want two lists corresponding to two columns A and B in the result. I can do this as ...
0
votes
0answers
28 views
Sqlalchemy get data after a long time
In openstack , I use below code to store IP address successfully :
'''
Now, just insert randomly IP v4/v6 address
'''
from horizon.conf import nvi_db
nvi = nvi_db.Nvi_Instance()
guest_uuid = ...
2
votes
0answers
65 views
How to populate lists of objects with WTForms?
Use case: using a form to enter grades for each course a student is enrolled in.
Model:
Using SQLAlchemy, I defined a Student object, a Course object, and a StudentCourse association object that ...
0
votes
2answers
25 views
sqlalchemy's UnicodeText column is giving me a str on my MySQL table; shouldn't it be unicode?
Let's say I have a simple table:
class MyTable(...):
__tablename__ = 'my_table'
id = ...
unicode_col = Column(UnicodeText())
Now I would like to get some data out of it:
assert ...
0
votes
1answer
40 views
SQLAlchemy first() without executing expression
I can't imagine, how to convert this SQL code to SQLAlchemy statements:
SELECT TaskID
FROM TaskPushes p
WHERE PushToEmployeeID = 5
AND PushDate = (
SELECT TOP 1 PushDate
FROM TaskPushes
...
0
votes
2answers
38 views
Is there a Non-Sqlalchemy way to deal with many-to-many relationships in Python?
I've searched for quite a long time on the web for a method that deals with many-to-many relationships in python sqlite3, but all seems to lead to Sqlalchemy. I'm not against using sqlalchemy at ...
0
votes
1answer
28 views
Multiple foreign keys in one column referencing the same table
I have a table called "Subtests" and a table called "TestSteps" (in a sqlite db using SQLalchemy) and I would like to allow for test steps to be shared amongst multiple subtests. This requires storing ...
0
votes
1answer
62 views
Flask-SQLAlchemy many to many join condition
I have 3 tables, Events, Invites, and Proposals. I would like to be able to query for events.invites and return a query of all invitees (and be able to get user's info from my user table, like ...
