Python 操作 PostgreSQL 数据库
2024-09-02 06:41:42
我使用的是 Python 3.7.0
PostgreSQL可以使用psycopg2
模块与Python集成。
sycopg2
是用于Python编程语言的PostgreSQL数据库适配器。
psycopg2
是非常小,快速,稳定的。 您不需要单独安装此模块,因为默认情况下它会随着Python 2.5.x
版本一起发布。
pip3 install python-psycopg2
pip3 install psycopg2-binary
连接到数据库
以下Python代码显示了如何连接到现有的数据库。 如果数据库不存在,那么它将自动创建,最后将返回一个数据库对象。
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="") print("Opened database successfully")
在这里指定使用testdb
作为数据库名称,如果数据库已成功打开连接,则会提供以下消息:
Open database successfully
创建表
以下Python程序将用于在先前创建的数据库(testdb
)中创建一个表:
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="")
print("Opened database successfully") cur = conn.cursor()
cur.execute('''CREATE TABLE COMPANY
(ID INT PRIMARY KEY NOT NULL,
NAME TEXT NOT NULL,
AGE INT NOT NULL,
ADDRESS CHAR(),
SALARY REAL);''')
print "Table created successfully" conn.commit()
conn.close()
当执行上述程序时,它将在数据库testdb
中创建COMPANY
表,并显示以下消息:
Opened database successfully
Table created successfully
插入操作
以下Python程序显示了如何在上述示例中创建的COMPANY
表中创建记录:
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="")
print("Opened database successfully") cur = conn.cursor() cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (, 'Paul', , 'California', 20000.00 )"); cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (, 'Allen', , 'Texas', 15000.00 )"); cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (, 'Teddy', , 'Norway', 20000.00 )"); cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
VALUES (, 'Mark', , 'Rich-Mond ', 65000.00 )"); conn.commit()
print("Records created successfully");
conn.close()
当执行上述程序时,它将在COMPANY
表中创建/插入给定的记录,并显示以下两行:
Opened database successfully
Records created successfully
SELECT操作
以下 Python 程序显示了如何从上述示例中创建的 COMPANY
表中获取和显示记录:
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="")
print("Opened database successfully") cur = conn.cursor() cur.execute("SELECT id, name, address, salary from COMPANY")
rows = cur.fetchall()
for row in rows:
print("ID = ", row[])
print("NAME = ", row[])
print("ADDRESS = ", row[])
print("SALARY = ", row[], "\n") print("Operation done successfully");
conn.close()
执行上述程序时,会产生以下结果:
Opened database successfully
ID =
NAME = Paul
ADDRESS = California
SALARY = 20000.0 ID =
NAME = Allen
ADDRESS = Texas
SALARY = 15000.0 ID =
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0 ID =
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0 Operation done successfully
更新操作
以下 Python 代码显示了如何使用UPDATE
语句来更新任何记录,然后从COMPANY
表中获取并显示更新的记录:
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="")
print("Opened database successfully") cur = conn.cursor() cur.execute("UPDATE COMPANY set SALARY = 25000.00 where ID=1")
conn.commit
print("Total number of rows updated :", cur.rowcount) cur.execute("SELECT id, name, address, salary from COMPANY")
rows = cur.fetchall()
for row in rows:
print("ID = ", row[])
print("NAME = ", row[])
print("ADDRESS = ", row[])
print("SALARY = ", row[], "\n") print("Operation done successfully");
conn.close()
Python
执行上述程序时,会产生以下结果:
Opened database successfully
Total number of rows updated : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 25000.0
ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000.0
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
删除操作
以下 Python 代码显示了如何使用 DELETE
语句来删除记录,然后从 COMPANY
表中获取并显示剩余的记录:
#!/usr/bin/python import psycopg2 conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="")
print("Opened database successfully") cur = conn.cursor() cur.execute("DELETE from COMPANY where ID=2;")
conn.commit
print("Total number of rows deleted :", cur.rowcount) cur.execute("SELECT id, name, address, salary from COMPANY")
rows = cur.fetchall()
for row in rows:
print("ID = ", row[])
print("NAME = ", row[])
print("ADDRESS = ", row[])
print("SALARY = ", row[], "\n") print("Operation done successfully");
conn.close()
执行上述程序时,会产生以下结果:
Opened database successfully
Total number of rows deleted : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 20000.0
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
https://www.yiibai.com/postgresql/postgresql_python.html
最新文章
- Spring mvc @initBinder 类型转化器的使用
- ASP.NET MVC3入门教程之参数(数据)传递
- 关于jquery中 跳出each循环的方法
- UVA 11754 (暴力+中国剩余定理)
- [CareerCup] 5.6 Swap Odd and Even Bits 交换奇偶位
- Web开发基础
- IPC是什么意思?
- b/s客户端和服务器的交互(转)
- mock server相关解决方案
- 常用的ASCII码对照表
- [CSS备忘]多行文本省略号
- Find Unique pair in an array with pairs of numbers 在具有数字对的数组中查找唯一对
- Codeforces 834D The Bakery【dp+线段树维护+lazy】
- 利用whoosh对mongoDB的中文文档建立全文检索
- 马凯军201771010116《面向对象与程序设计Java》第十一周学习总结
- web前端(11)—— 页面布局1
- VKD224B触摸芯片调试笔记
- python sqlite3 数据库操作
- node mongodb 案例代码
- pdo的用处,用法
热门文章
- 阻止Bootstrap 模态框(Modal)点击空白处时关闭
- DataView RowFilter
- java Vamei快速教程13 String类
- 论overflow滚动的重要性
- 【BZOJ2754】[SCOI2012] 喵星球上的点名(后缀数组+莫队)
- 【洛谷3157】[CQOI2011] 动态逆序对(CDQ分治)
- 【luogu P1783 海滩防御】 题解
- java编程基础——二叉树的镜像
- ABC108C - Triangular Relationship(打表)
- Linux分享笔记:查看帮助命令 &; 常用系统工作命令