Ponyorm: Introduction to the ORM framework based on the Pythonic style in Python

Ponyorm is a Pythonic style ORM (object relationship mapping) framework, which aims to simplify database operation and query process.This article will introduce the characteristics, usage, usage and related configuration and programming code of Ponyorm. 1 Introduction ORM is a technology that maps the database table, records and objects.It can directly map the object into a record of the database table in the programming language, thereby providing a more object -oriented database operation method.Ponyorm is such an ORM framework that provides a simple and intuitive API, which aims to help developers perform database access and query operations more efficiently. 2. Features Ponyorm has the following features: -It is easy to use: Ponyorm's API design is in line with the Pythonic style, so that developers can complete complex database operations with fewer code. -The performance optimization: Ponyorm supports high -performance data query, which can use pre -loading, delay loading and other technologies to improve query efficiency. -Ponym support: Ponyorm can interact with a variety of relational databases, including MySQL, PostgreSQL and SQLITE. -Data model definition: Describe the database table structure by defining the Python class and attributes, so that developers can use object -oriented methods for database operations. -Finding expression: Ponyorm provides a strong query expression, supports commonly used query operations such as filtering, sorting, grouping, and aggregation. -Adow support: Ponyorm can handle database transactions to ensure the consistency and integrity of data. 3. Installation and configuration Before using Ponyorm, you need to install the Ponyorm library through PIP.You can run the following commands in the command line for installation: pip install pony After the installation is completed, you can introduce ponyorm through the Import statement: import pony.orm as pony 4. Data model definition Before using Ponyorm for database operations, data models need to be defined.The data model consists of the Python class and class attributes. Each class represents a database table, which represents the field in the table.The following is a simple example: python from pony.orm import * db = Database() class User(db.Entity): id = PrimaryKey(int, auto=True) name = Required(str) age = Required(int) db.generate_mapping(create_tables=True) In the above example, a data model called User is defined, including three properties: ID, name, and Age.Among them, ID is defined as the self -increase primary key, and name and Age are defined as a required field. 5. Database connection and operation In Ponyorm, use DB_SESSION decorative device to create a database session and establish a connection with the database.Database operations can be performed through session objects, such as adding, modifying and querying.The following is a simple example: python @pony.db_session def create_user(name: str, age: int): user = User(name=name, age=age) return user @pony.db_session def get_users(): return select(user for user in User)[:] user = create_user("Alice", 25) users = get_users() for user in users: print(user.name, user.age) In the above example, add a record to the User table through the Create_user function, query all users through the get_users function, and print the name and age of each user in a cycle. 6. Query expression In addition to the simple queries in the above examples, Ponyorm also provides a wealth of query expression to complete more complex query operations.For example, the filtering conditions, sorting methods and paging operations can be used to limit the query results.The following is an example: python @pony.db_session def filter_users(min_age: int): return select(user for user in User if user.age >= min_age).order_by(User.age)[:10] filtered_users = filter_users(20) for user in filtered_users: print(user.name, user.age) In the above examples, the Filter_users function obtains the top 10 users with more than 20 users with a query expression with filtering conditions and sorting methods. In summary, Ponyorm is a Pythonic style ORM framework in Python. Through simple API and powerful query expressions, developers can operate and query more efficiently.Using Ponyorm, developers can use less code to achieve complex database operations, and can interact with multiple relational databases.