这里写目录标题
- 前言
- 1、安装PyMySQL
- 2、打开要连接的数据库
- 3、创建数据库连接
- 4、获取数据库版本
- 5、新建数据库表
- 6、向表中插入数据
- 7、查询表中的相关记录
- 8、更新表中的相关记录
- 9、删除表中的相关记录
- 10、关闭游标和连接
- 完整代码
前言
本文演示了如何基于PyMySQL使用代码来创建数据库连接、新建数据库表、向表中插入数据、查询表中的相关记录、更新表中的相关记录、删除表中的相关记录等操作，最后，要记得关闭游标和连接。
1、安装PyMySQL
如果是使用Anaconda来管理包和Python环境，则可以使用 s t e p 1 step1 step1和 s t e p 2 step2 step2来创建一个独立的环境方便管理；如果不是可直接执行 s t e p 3 step3 step3将PyMySQL包安装到本地已有的Python环境中。
s t e p 1 ： step1： step1：创建一个虚拟环境
conda create -n use_mysql python=3.6
s t e p 2 ： step2： step2：激活虚拟环境
conda activate use_mysql
s t e p 3 ： step3： step3：使用清华源安装PyMySQL
pip install PyMySQL -i https://pypi.tuna.tsinghua.edu.cn/simple
2、打开要连接的数据库
我这里使用的是Navicat Premium 16连接一个名称为 “test” 的数据库。
3、创建数据库连接
import pymysql
# 设置数据库连接参数
db_params = {
'host': 'localhost', # 数据库服务器地址
'user': 'root', # 数据库用户名
'password': '123456', # 数据库密码
'db': 'test', # 要连接的数据库名称
'charset': 'utf8mb4', # 编码方式
}
# 创建数据库连接
try:
connection = pymysql.connect(**db_params)
print("Database connection successful.")
except pymysql.MySQLError as e:
print(f"Error connecting to MySQL Platform: {e}")
运行代码，连接成功后控制台会打印输出 “Database connection successful.”
4、获取数据库版本
# 获取游标对象
cursor = connection.cursor()
# 获取数据库版本
cursor.execute("SELECT VERSION();")
data = cursor.fetchone()
print("Database version: %s " % data)
5、新建数据库表
# 检查表student是否已经存在于数据库test中
cursor.execute("SHOW TABLES LIKE 'STUDENT'")
result = cursor.fetchone()
if result:
print("Table 'STUDENT' already exists.")
else:
# 创建表
cursor.execute("""
CREATE TABLE STUDENT (
num INT NOT NULL,
name CHAR(20),
age INT,
sex CHAR(10)
)
""")
connection.commit()
print("Table 'STUDENT' created successfully.")
6、向表中插入数据
# 向student表中插入数据
insert_sql_1 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (1, 'zhangsan', 20, 'Man')"
insert_sql_2 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (2, 'lisi', 18, 'Woman')"
insert_sql_3 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (3, 'wangwu', 21, 'Man')"
insert_sql_4 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (4, 'zhaoliu', 19, 'Woman')"
try:
cursor.execute(insert_sql_1)
cursor.execute(insert_sql_2)
cursor.execute(insert_sql_3)
cursor.execute(insert_sql_4)
connection.commit()
print("Successfully inserted data into the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
运行代码后，回到 Navicat Premium 16 查看插入的数据。
7、查询表中的相关记录
# 查询student表中name字段值为'zhangsan'的所有记录
query_sql = "SELECT * FROM student WHERE name='zhangsan'"
try:
cursor.execute(query_sql)
results = cursor.fetchall() # 获取所有查询结果
print("The query results are as follows:")
for row in results:
print(row) # 打印每一行结果
connection.commit()
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
8、更新表中的相关记录
# 更新student表中num字段值为3的记录的name字段为'newname'：
update_sql = "UPDATE student SET name = 'newname' WHERE num = 3"
try:
cursor.execute(update_sql)
connection.commit()
print("Successfully updated data in the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
9、删除表中的相关记录
# 删除student表中num字段值为4的所有记录
delete_sql = "DELETE FROM student WHERE num = 4"
try:
cursor.execute(delete_sql)
connection.commit()
print("Successfully deleted data from the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
10、关闭游标和连接
# 关闭游标和连接
cursor.close()
connection.close()
完整代码
import pymysql
# 设置数据库连接参数
db_params = {
'host': 'localhost', # 数据库服务器地址
'user': 'root', # 数据库用户名
'password': '123456', # 数据库密码
'db': 'test', # 要连接的数据库名称
'charset': 'utf8mb4', # 编码方式
}
# 创建数据库连接
try:
connection = pymysql.connect(**db_params)
print("Database connection successful.")
except pymysql.MySQLError as e:
print(f"Error connecting to MySQL Platform: {e}")
# 获取游标对象
cursor = connection.cursor()
# 获取数据库版本
cursor.execute("SELECT VERSION();")
data = cursor.fetchone()
print("Database version: %s " % data)
# 检查表student是否已经存在于数据库test中
cursor.execute("SHOW TABLES LIKE 'STUDENT'")
result = cursor.fetchone()
if result:
print("Table 'STUDENT' already exists.")
else:
# 创建表
cursor.execute("""
CREATE TABLE STUDENT (
num INT NOT NULL,
name CHAR(20),
age INT,
sex CHAR(10)
)
""")
connection.commit()
print("Table 'STUDENT' created successfully.")
# 向student表中插入数据
insert_sql_1 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (1, 'zhangsan', 20, 'Man')"
insert_sql_2 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (2, 'lisi', 18, 'Woman')"
insert_sql_3 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (3, 'wangwu', 21, 'Man')"
insert_sql_4 = "INSERT INTO STUDENT(num, name, age, sex) VALUES (4, 'zhaoliu', 19, 'Woman')"
try:
cursor.execute(insert_sql_1)
cursor.execute(insert_sql_2)
cursor.execute(insert_sql_3)
cursor.execute(insert_sql_4)
connection.commit()
print("Successfully inserted data into the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
# 查询student表中name字段值为'zhangsan'的所有记录
query_sql = "SELECT * FROM student WHERE name='zhangsan'"
try:
cursor.execute(query_sql)
results = cursor.fetchall() # 获取所有查询结果
print("The query results are as follows:")
for row in results:
print(row) # 打印每一行结果
connection.commit()
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
# 更新student表中num字段值为3的记录的name字段为'newname'：
update_sql = "UPDATE student SET name = 'newname' WHERE num = 3"
try:
cursor.execute(update_sql)
connection.commit()
print("Successfully updated data in the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
# 删除student表中num字段值为4的所有记录
delete_sql = "DELETE FROM student WHERE num = 4"
try:
cursor.execute(delete_sql)
connection.commit()
print("Successfully deleted data from the table.")
except Exception as e: # 捕获所有异常
print(f"An error occurred: {e}")
connection.rollback()
# 关闭游标和连接
cursor.close()
connection.close()
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