Ponyorm: Introduction to the class library in python

Ponyorm: Introduction to the class library in python introduction: In the world of Python, we often need to store and retrieve data through interaction with the database.To simplify this process, many database operating libraries have been developed.Among them, Ponyorm is a powerful and easy -to -use Python class library. It provides simple API and advanced query functions for processing database operations. 1. What is ponyorm? Ponyorm is an open source Python library for database access and object relationship mapping (ORM).It provides a simple and intuitive way to operate the database so that developers can focus more on business logic rather than database details. 2. Main features 2.1 Entity (Entity) class definition In Ponyorm, the database table is mapped to the Python class.Use the decorative `@pony.orm.db_session`, we can use the database operation in the class definition.For example: python from pony import orm db = orm.Database() class Person(db.Entity): name = orm.Required(str) age = orm.Required(int) db.bind(provider='sqlite', filename='database.sqlite', create_db=True) db.generate_mapping(create_tables=True) In the above code, the `@pony.orm.db_session` decorator provides us with a database context, we can perform the database operation in it.The `Person` class represents a database table, which corresponds to the field of the table of the` name` and `age` properties. 2.2 Query data Ponyorm provides a strong query grammar to retrieve data in the database.For example, we can use the `.select ()` method to obtain data that meets specific conditions: python users = orm.select(u for u in User if u.age > 18) The above code will obtain all users older than 18 in the database. 2.3 Relationship mapping In addition to the basic database table operation, Ponyorm also provides a relationship mapping function to process the relationship between database tables.For example, we can define a relationship of one -pair: python class Book(db.Entity): title = orm.Required(str) author = orm.Required(Person) In the above code, the `author` attribute of the` Book` class defines the relationship with the `Person` class.This means that an author (`Person`) can have multiple books (` Book`). 3. Configuration and use To use Ponyorm, we need to install it first.You can use PIP to install through the following command: pip install pony After the installation is completed, we can import the `Pony.orm` module in the Python code to use the Ponyorm function. 4 Conclusion Ponyorm is a powerful and easy -to -use Python class library for database operation and object relationship mapping.It provides simple API and advanced query functions, making the operating database more intuitive and simple.Whether it is novices or experienced developers, they can easily interact with databases through Ponyorm. In short, if you are using Python to develop database -related applications, Ponyorm is a class library worth considering, which can significantly simplify database operations and provide many useful functions.Come and try it!