MySql and ORM framework: How to implement database operations more efficiently

With the rapid development of Internet technology, database applications have become more and more widespread, and the most widely used one is MySql. As a stable, secure, easy-to-use and high-performance relational database, MySql's application range covers a variety of scenarios. Whether in various fields such as e-commerce, finance, electricity, agriculture, etc., MySql plays an increasingly important role.

However, in the actual development process, we often need to perform complex data operations. At this time, simple MySql query statements may not meet our needs. At this time, we need to use some more advanced technology to operate on data. At this time, the ORM framework came into being.

ORM framework, that is, object-relational mapping framework, is a technology that corresponds tables in relational databases to classes in object-oriented programming. The ORM framework can help us perform various database operations more efficiently, and can be used in different programming languages, such as Java, Python, etc. Below we will introduce how to use MySql and ORM framework to implement database operations more efficiently.

1. Use MySql to add, delete, modify and check data

Let’s first look at using MySql to add, delete, modify and check data. MySql provides very simple SQL statements, which we can easily use to perform various operations on the database. For example, the following is a simple student information table:

CREATE TABLE student(
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(30),
    age INT
);

We can use the following SQL statement to insert a piece of data into the table:

INSERT INTO student(name, age) VALUES('Tom', 18);

Use the following SQL statement to perform query operations:

SELECT * FROM student WHERE name = 'Tom';

Use the following SQL statement for update operations:

UPDATE student SET age=19 WHERE name='Tom';

Use the following SQL statements for delete operations:

DELETE FROM student WHERE name='Tom';

Using MySql for data operations is simple, but if we need to implement something more complex To operate, you need to use some advanced techniques.

2. Use the ORM framework to add, delete, modify and query data

Using the ORM framework can perform database operations more efficiently. Next, we will use the ORM framework in Python - SQLAlchemy to demonstrate how to perform database operations.

1. Installing SQLAlchemy

We first need to install SQLAlchemy. Use the following command to install:

pip install sqlalchemy

2. Connect to the database

When connecting to the database, we need to use the following code:

from sqlalchemy import create_engine

engine = create_engine('mysql+pymysql://user:password@host:port/database_name?charset=utf8')

where user is The user name of the MySqL database; password is the password; host is the host name; port is the port number; database_name is the name of the database to be connected; charset is the encoding method, here we use utf8.

3. Define the ORM model

The mapping relationship between the ORM model and the table needs to be defined. For example, we define a table model for a student information table, the code is as follows:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String

Base = declarative_base()

class Student(Base):
    __tablename__ = 'student'

    id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(30))
    age = Column(Integer)

We use the declarative_base() base class provided by SQLAlchemy to let us define the table model class, and then define the fields of the table in the Student class name and type. Note that __tablename__ must be specified here, which is the corresponding table name.

4. Create session

When creating a session, you need to create a session factory first, and then use the session factory to create the session. As shown below:

from sqlalchemy.orm import sessionmaker

Session = sessionmaker(bind=engine)
session = Session()

Among them, sessionmaker(bind=engine) means using the engine returned by create_engine to bind sessionmaker. Then we can use session to access the database for operations.

5. Add, delete, modify and query data

Next we will demonstrate how to perform add, delete, modify and query operations respectively.

(1) Add data

Use the following code to add data:

student = Student(name='Tom', age=18)
session.add(student)
session.commit()

This example demonstrates how to create a Student object and add it to the session, and Use the session.commit() method to submit data to the database. If the session.commit() method is not called, the data will not be submitted to the database.

(2) Query data

Use the following code to query data:

results = session.query(Student).filter(Student.name=='Tom').all()
for result in results:
    print(result.id, result.name, result.age)

This example demonstrates how to use session to query the table, where query(Student) means To operate on the Student table, filter(Student.name=='Tom') means to filter out data whose name field is equal to Tom, and all() means to query all data.

(3) Modify data

Use the following code to modify data:

update_student = session.query(Student).filter(Student.name=='Tom').first()
update_student.age = 19
session.commit()

This example demonstrates how to modify the first piece of data that meets the conditions and change the age of the data The value is 19, and the session.commit() method is used to commit the modified data.

(4) Delete data

Use the following code to delete data:

delete_student = session.query(Student).filter(Student.name=='Tom').first()
session.delete(delete_student)
session.commit()

This example demonstrates how to delete the first piece of data that meets the conditions and use session.commit () method to submit the deleted data.

At this point, we can happily use Python and SQLAlchemy to manage our database more efficiently.

Summary:

As a commonly used relational database, MySql is simple and intuitive to use, but complex operations may require the use of more advanced technologies. The ORM framework can help us perform complex database operations more efficiently, and using Python and SQLAlchemy can help us better cope with the database needs in our daily work. I hope this article can help you better master the use of MySql and ORM framework.

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