文章目录

• • @[toc]
  • • 创建数据库
    • 创建数据表
    • 数据插入
    • 数据查询
    • 数据更新

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系列专栏：Python数据库

学习指南：Python学习指南

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创建数据库

import pymysqldef create_database():db = pymysql.connect(host='localhost', user='root', password='root')cursor = db.cursor()sql = """create database if not exists python_database charset=utf8;"""try:cursor.execute(sql)except Exception as e:print(f'数据库创建失败: {e}')else:print('数据库创建成功...')if __name__ == '__main__':create_database()

• pymysql.connect(host='localhost', user='root', password='root')用于连接数据库
  • host用于指定数据库IP地址，localhost表示本地
  • user用于指定数据库用户名
  • password用于指定数据库密码
• db.cursor()返回一个游标对象，用于执行数据库操作
• cursor.execute(sql)用于执行一条SQL语句

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创建数据表

import pymysqldef create_table():db = pymysql.connect(host='localhost', user='root', password='root', db='python_database')cursor = db.cursor()sql = """create table if not exists book_info(id int primary key auto_increment,name varchar(10) not null,pub_date datetime,read_count int,comment_count int,is_delete bit);"""try:cursor.execute(sql)except Exception as e:print(f'数据表创建失败: {e}')else:print('数据表创建成功...')finally:cursor.close()db.close()if __name__ == '__main__':create_table()

数据插入

import pymysqldef insert_data():with pymysql.connect(host='localhost', user='root', password='root', db='python_database') as db:cursor = db.cursor()sql = """insert into book_info (id, name, pub_date, read_count, comment_count, is_delete) values (%s, %s, %s, %s, %s, %s);"""try:cursor.executemany(sql, [(0, '射雕英雄传', '1980-5-1', 12, 34, 0),(0, '天龙八部', '1986-7-24', 36, 40, 0),(0, '笑傲江湖', '1995-12-24', 20, 80, 0),(0, '雪山飞狐', '1987-11-11', 58, 24, 0)])db.commit()except Exception as e:print(f'数据插入失败: {e}')db.rollback()else:print('数据插入成功...')if __name__ == '__main__':insert_data()

• db.commit()用于事务提交
• db.rollback()用于在数据插入失败时进行事务回滚

数据查询

import pymysqldef query_data():db = pymysql.connect(host='localhost', user='root', password='root', db='python_database')cursor = db.cursor()sql = """select * from book_info;"""try:cursor.execute(sql)except Exception as e:print(f'数据查询失败: {e}')else:result = cursor.fetchall()# result = cursor.fetchone()# result = cursor.fetchmany(4)for book in result:book_info = dict()book_info['id'] = book[0]book_info['name'] = book[1]book_info['pub_date'] = book[2]book_info['read_count'] = book[3]book_info['comment_count'] = book[4]book_info['is_delete'] = book[5]print(book_info)finally:cursor.close()db.close()if __name__ == '__main__':query_data()

{'id': 1, 'name': '射雕英雄传', 'pub_date': datetime.datetime(1980, 5, 1, 0, 0), 'read_count': 12, 'comment_count': 34, 'is_delete': b'\x00'}
{'id': 2, 'name': '天龙八部', 'pub_date': datetime.datetime(1986, 7, 24, 0, 0), 'read_count': 36, 'comment_count': 40, 'is_delete': b'\x00'}
{'id': 3, 'name': '笑傲江湖', 'pub_date': datetime.datetime(1995, 12, 24, 0, 0), 'read_count': 20, 'comment_count': 80, 'is_delete': b'\x00'}
{'id': 4, 'name': '雪山飞狐', 'pub_date': datetime.datetime(1987, 11, 11, 0, 0), 'read_count': 58, 'comment_count': 24, 'is_delete': b'\x00'}

• cursor.fetchall()用于获取所有查询结果
• cursor.fetchone()用于获取一条查询结果
• cursor.fetchmany(4)用于获取四条查询结果

数据更新

import pymysqldef update_data():db = pymysql.connect(host='localhost', user='root', password='root', db='python_database')cursor = db.cursor()sql = """update book_info set read_count = read_count + 1 where id = 1;"""try:cursor.execute(sql)db.commit()except Exception as e:print(f'数据更新失败: {e}')db.rollback()else:print('数据更新成功...')finally:cursor.close()db.close()if __name__ == '__main__':update_data()

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