sqlalchemy

Using the SQLAlchemy ORM inside an Alembic migration: how do I?

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After a bit of experimentation using @velochy’s answer, I settled on something like the following pattern for using SqlAlchemy inside Alembic. This worked great for me and could probably serve as a general solution for the OP’s question: from sqlalchemy.orm.session import Session from alembic import op # Copy the model definitions into the migration script … Read more

Setting delete-orphan on SQLAlchemy relationship causes AssertionError: This AttributeImpl is not configured to track parents

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OK in this case, you need to look more closely, though there is a warning here that likely should become an exception, and I’ll look into that. Here’s a working version of your example: from sqlalchemy.ext.associationproxy import association_proxy from sqlalchemy import * from sqlalchemy.orm import * from sqlalchemy.ext.declarative import declarative_base Base= declarative_base() tagging = Table(‘tagging’,Base.metadata, … Read more

Share sqlalchemy models between flask and other apps

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The Flask-SQLAlchemy extension, like most Flask extensions, should be created outside the factory, then initialized in the factory using init_app. This is so that you can use the db object before an app is created. db = SQLAlchemy() def create_app(): app = Flask(__name__) db.init_app(app) return app Your Flask app, like any properly designed Python project, … Read more

SQLAlchemy can’t connect to an mssql database

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If not specified in the URL, the default driver for the mssql+pyodbc dialect would be “SQL Server” [1]. That means you need to have a section that reads like this in /etc/unixODBC/odbcinst.ini: [SQL Server] Driver=/path/to/library.so It works “automatically” on Windows, because if you open Administrator Tools -> Data Sources (ODBC), you would most likely find … Read more

SQLAlchemy INSERT IGNORE

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prefix_with(“TEXT”) adds arbitrary text between INSERT and the rest of the SQL. execute() accepts a list of dictionaries with the records you would like to insert or a single dictionary if you only want to insert a single record. The SQLite syntax for the behavior you’re looking for: inserter = table_object.insert().prefix_with(“OR REPLACE”) inserter.execute([{‘column1′:’value1’}, {‘column1′:’value2’}])

Setting SQLAlchemy autoincrement start value

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You can achieve this by using DDLEvents. This will allow you to run additional SQL statements just after the CREATE TABLE ran. Look at the examples in the link, but I am guessing your code will look similar to below: from sqlalchemy import event from sqlalchemy import DDL event.listen( Article.__table__, “after_create”, DDL(“ALTER TABLE %(table)s AUTO_INCREMENT … Read more