![]() The first argument to the db.Column() constructor is the type of the column you want to create. If you don't want to rely on this behavior use _tablename_ variable to explicitly name the table. By default, SQLAlchemy doesn't conform to the convention of creating plural names and creates table name after the model name. The _tablename_ is a special class variable used to define the name of the database table. Each class variable except _tablename_ is an instance of db.Column class. Here we are creating a Post model class with 5 class variables. ![]() Text (), nullable = False ) created_on = db. String ( 255 ), nullable = False ) content = db. String ( 255 ), nullable = False ) slug = db. Integer (), primary_key = True ) title = db. from flask_sqlalchemy import SQLAlchemy from datetime import datetime #. Install Flask-SQLAlchemy and its dependencies using the following command: In addition to that, it also provides some helper methods to make working with SQLAlchemy a little easier. Of course, we are not bound to use ORM in any way, if the need arises then we can use SQL too.įlask-SQLAlchemy is an extension which integrates SQLAlchemy framework with Flask. SQLAlchemy comes with a powerful ORM ( Object Relational Mapper ) which allows us to work with various databases using Object Oriented code instead of writing raw SQL. SQLAlchemy supports databases like MySQL, PostgreSQL, Oracle, MS-SQL, SQLite and so on. SQLAlchemy is the de facto framework for working with relational databases in Python. In fact, there are some scenarios where NoSQL databases make more sense than a Relational Database but for now, our discussion will be restricted to relational databases only. That doesn't mean NoSQL databases are of no use. Consequently, the rest of this lesson specifically discusses how to use Relational databases with Flask. They have proven themselves to be reliable and secure across many industries. Relational databases are very mature as compared to NoSQL databases. Most NoSQL also do not support transaction but they do offer lots of speed. NoSQL databases do not store data in tables and columns instead they use structures like document stores, key-value stores, graphs etc. In recent years NoSQL databases have grown in popularity. By atomic I mean either all statements in the transaction executed successfully or nothing executed at all. Relational databases also support transaction which simply means that you can execute a set of SQL statements that needs to be atomic. Relational databases stores data in tables and columns and uses a foreign key to establish a relationship between one or more tables. Many big players on the web like Facebook are still using it. Relational databases have been used traditionally in web application. Today we have two types of competing Database systems: In this lesson, we will learn how to interact with the database. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |