python怎么创建数据库

import sqlite3
<h1>连接（若 test.db 不存在，则自动创建）</h1><p>conn = sqlite3.connect('test.db')</p><h1>可选：创建一张表，验证数据库已就绪</h1><p>cursor = conn.cursor()
cursor.execute('CREATE TABLE IF NOT EXISTS users (id INTEGER PRIMARY KEY, name TEXT, age INTEGER)')
conn.commit()
conn.close()

import pymysql
<h1>先连到 MySQL 服务器（不指定具体库）</h1><p>conn = pymysql.connect(
host='localhost',
user='root',
password='your_password',
charset='utf8mb4'
)</p><p>cursor = conn.cursor()
cursor.execute("CREATE DATABASE IF NOT EXISTS myapp_db")
conn.close()

import psycopg2
<p>conn = psycopg2.connect(
host='localhost',
user='postgres',
password='your_password',
database='postgres'  # 必须连到默认库（如 postgres）才能建新库
)
conn.autocommit = True  # 建库语句不能在事务中，需开启自动提交
cursor = conn.cursor()
cursor.execute("CREATE DATABASE myapp_db")
conn.close()

from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
<p>Base = declarative_base()</p><p>class User(Base):
<strong>tablename</strong> = 'users'
id = Column(Integer, primary_key=True)
name = Column(String(50))
age = Column(Integer)</p><h1>创建引擎（test.db 不存在则自动创建）</h1><p>engine = create_engine('sqlite:///test.db', echo=True)</p><h1>创建所有表（对应 Base 的子类）</h1><p>Base.metadata.create_all(engine)