The Engine expects a Database URL as input during instantiation. The following architecture diagram illustrates the structure (). These in turn work with DBAPI behind the scenes to translate data to and from our app/database. The engine internally references a Dialect object that handles communication and a Pool object that handles connections. At a high level, the engine takes input from our Python application and processes the information and converts it into output understood by our SQL database. The Engine is at the heart of the SQLAlchemy library. For simplicity, SQLite is used but settings can be upgraded with ease to use more powerful DBMS like MySQL or PostgreSQL. The necessary code is added progressively on top of a simple codebase from zero to the migration phase. In this tutorial, we will look at how you can use Flask-SQLAlchemy with your AWS RDS database. Flask-SQLAlchemy is the Flask extension that adds support for SQLAlchemy to your Flask application. This article explains how to configure and connect Flask to an SQLite Database using SqlAchemy as a connection layer. It provides a clean interface for defining database schemas and mapping between those schemas and Python classes. SQLAlchemy is a powerful tool for building object oriented applications. In other words, it helps programmers build applications that interact with databases. SQLAlchemy is a Python library designed to simplify data access and manipulation. Interested in SQL ? Check out this SQL Certification by Intellipaat.Flask-SQLAlchemy is an extension for Flask that adds support for SQLAlchemy to your application. You could be able to use your SQLite code to work with MySQL with the URI mapped as in above code. The purpose of using ORM like SQLAlchemy is that you can use a different database with limited or no change in most cases. config = 'mysql+pymysql://username: /db_name' When you install it using pip install pymysql, the SQLALCHEMY_DATABASE_URI will be changing to: app. So I had opted for the MySQL driver with full python implementation pymysql. It was found that the default driver used by the SQLAlchemy ( mqsqldb), didn't get compiled for me in the virtual environment. Else remove it.ĭb.mit() # This is needed to write the changes to database In case your server is not running in the same machine, Put the server IP in place of the localhost.īelow is your code with some little changes: from flask import FlaskĪpp.config = 'mysql://username: /db_name'ĭb.create_all() # In case user table doesn't exists already. My assumptions are your MySQL server is running on the same machine where Flask is also running and the database name is db_name. Would work without any of the changes rather than a proper modification to the database URI, though the examples I had found for using the SQLAlchemy with the MySQL appear to be using a totally different API.Ĭan I (2) migrate my Flask SQLAlchemy code to work with the MySQL database by just modifying the database URI and if so (1) what should be that URI? Username = db.Column(db.String( 80), unique= True)Įmail = db.Column(db.String( 120), unique= True)ĭef _repr_( self): return '' % ernameĪdmin = User( 'admin', ' ') You will learn how to use SQLite joins to query data from two tables and how to group to-do items by their lists. But I am really worried about (2), I had assumed that SQLAlchemy provided an abstraction layer so that simple SQLAlchemy code such as from flask import Flaskįrom import SQLAlchemyĪpp.config = 'sqlite:////tmp/test.db'Ĭlass User( db.Model): id = db.Column(db.Integer, primary_key= True) In this step, you will connect the database you created in the previous step to a Flask application that displays the to-do lists and the items of each list. I presume that (1) is moderately simple and just a matter of being shown how to map, for example, the contents of the connection dialogue I use in my MySQL database tool to an appropriately formatted URL. The following database diagram illustrates the chinook database.
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