Questions tagged [sqlalchemy]
Use this tag for the eponymous Python SQL toolkit and Object Relational Mapper.
19
questions
-1
votes
0answers
25 views
Simple inventory management db design - polymorphic association?
I’m designing a web application for internal use to inventory-manage returnable/reusable widgets (a physical product). I anticipate around a 100 or so ‘stock/widget transactions’ per day.
In simple ...
0
votes
1answer
22 views
Generated DDL doesn't match with CREATE TABLE statement
I'm using MySQL with InnoDB engine. I create a new table that contains a foreign key, eg:
CREATE TABLE rooms (
id INTEGER NOT NULL AUTO_INCREMENT,
my_id VARCHAR(15),
house_id INTEGER,
...
0
votes
0answers
3 views
using ORDER BY instead of PARTION BY row_number().over() [migrated]
While using sqlalchemy.func.rownumber().over its generating PARTITION BY how to change it to ORDER BY.
query = session.query(
sqlalchemy.func.row_number().over(Record.id).label('#'),
Record....
0
votes
0answers
4 views
Python Pandas to sqlite [migrated]
Hello I am new I had a question so I am trying to create a simple api using flask ..
the data I have is in CSV and I want to import it in to SQLlite file .. which I have done. and can access the ...
0
votes
1answer
34 views
Ram consumed by single query in Postgres using SqlAlchemy
I have a list of 36 queries ranging from low complexity(No joins) to high complexity(joins with subquery). I want to find the RAM Consumed by each query.
This is required for performance testing for ...
0
votes
1answer
542 views
How to Bulk Insert sqlalchemy subclasses
I am trying to bulk insert SQL-Alchemy Subclasses into the parent table and their respective tables ie fruits tables -> Apple Table and so I insert a table of APPLE and it will insert both the row ...
0
votes
2answers
35 views
Database design question: Tags with values(duration) linked to them
I am creating a database that takes in daily inputs such as:
Date
Events in that date (e.g. project foo: 5 hours, bar: 2 hours, etc...)
Rating of the date
There's more but these are probably the ...
0
votes
0answers
65 views
PostgreSQL & Pandas DF: is it possible to update a selection of data of a PostgreSQL db with a DF w/o impacting other entries?
I have a PostgreSQL database, which I interact with using SQLAlchemy in Python.
The database contains daily price data (including non-working days), starting from Jan-2005; the date column is the ...
0
votes
1answer
1k views
convert SQL query to SQLAlchemy query [closed]
I am having a lot of trouble in converting the below SQL query to SQLAlchemy query. Please help:
insert into conform_layer (unique_no,key_name,value_name)
SELECT id, key, value FROM (select ...
0
votes
1answer
5k views
How to set a auto-increment value in SQLAlchemy?
This is my code :
class csvimportt(Base):
__tablename__ = 'csvimportt'
#id = Column(INTEGER, primary_key=True, autoincrement=True)
aid = Column(INTEGER(unsigned=True, zerofill=...
0
votes
0answers
52 views
How to “lock” a table for select
I have a table called assignments. A user will request an assignment from an API endpoint. I need to ensure that an assignment can only be handed to one user. There will be multiple users requesting ...
0
votes
1answer
920 views
Converting a date to a datetime in MySQL
I'm supposed to add time to a date field. We use MySQL with python3, alembic and sqlalchemy. Now I've written a conversion program. It is my first program of such a kind. I'm not certain how it will ...
1
vote
0answers
782 views
UUID default value on PSQL
I'm creating my database tables inside a flask application via SQLAlchemy.
According to this answer, my code should look like this:
id = db.Column(db.CHAR(36), primary_key=True, server_default=str("...
0
votes
1answer
3k views
Why are my queries taking so long? [closed]
In order to quickly calculate some features for later calculations I have attempted to store a table that allows looking up distances between locations that have been pre-calculated. I am using Python ...
1
vote
0answers
170 views
Multiple many-to-many database relations
SO told me to ask here, so this is just copy-pasted from over there
We're making a database of anime. Every anime can be listed as having been made by an arbitrary number of studios, and every studio ...
2
votes
1answer
458 views
Database relationship inheritance [closed]
I have a vehicle sales store. In my store I sale many kind of vehicles for example cars and boats. And I would like to keep track of the sales.
My vehicles has some attributes as:
Arrive on store ...
3
votes
0answers
397 views
SELECT query blocking writes in postgresql
We have a web application that sends emails with a queue worker. Before an email is sent we write to a table:
INSERT INTO user_email (user_id, email_key, sent_at) VALUES (
175413579283955991,
...
0
votes
1answer
254 views
Use of MySQL trigger to insert row's week number
I have a table of orders in a MariaDB database that currently has a datetime column. For the dashboard I am building for this database, I have a statistic I would like to display which is "Orders This ...
3
votes
3answers
3k views
Performance of count(*) in subquery
Suppose we have the following queries:
1.
SELECT COUNT(*) FROM some_big_table WHERE some_col = 'some_val'
2.
SELECT COUNT(*) FROM ( SELECT * FROM some_big_table WHERE some_col = 'some_val' ...
