我使用的是 Python 3.7.0

PostgreSQL可以使用psycopg2模塊與Python集成。

sycopg2是用於Python編程語言的PostgreSQL數據庫適配器。

psycopg2是非常小，快速，穩定的。 您不需要單獨安裝此模塊，因為默認情況下它會隨著Python 2.5.x版本一起發布。

pip3 install python-psycopg2
pip3 install psycopg2-binary

連接到數據庫

以下Python代碼顯示了如何連接到現有的數據庫。 如果數據庫不存在，那麽它將自動創建，最後將返回一個數據庫對象。

#!/usr/bin/python

import psycopg2

conn 
 
= psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")

print("Opened database successfully")

在這裏指定使用testdb作為數據庫名稱，如果數據庫已成功打開連接，則會提供以下消息：

Open database successfully

創建表

以下Python程序將用於在先前創建的數據庫(testdb)中創建一個表：

#!/usr/bin/python

import psycopg2

conn = psycopg2.connect(database="
 
testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")
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(
 
50),
       SALARY         REAL);‘‘‘)
print "Table created successfully"

conn.commit()
conn.close()

當執行上述程序時，它將在數據庫testdb中創建COMPANY表，並顯示以下消息：

Opened database successfully
Table created successfully

插入操作

以下Python程序顯示了如何在上述示例中創建的COMPANY表中創建記錄：

#!/usr/bin/python

import psycopg2

conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")
print("Opened database successfully")

cur = conn.cursor()

cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
      VALUES (1, ‘Paul‘, 32, ‘California‘, 20000.00 )");

cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
      VALUES (2, ‘Allen‘, 25, ‘Texas‘, 15000.00 )");

cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
      VALUES (3, ‘Teddy‘, 23, ‘Norway‘, 20000.00 )");

cur.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) \
      VALUES (4, ‘Mark‘, 25, ‘Rich-Mond ‘, 65000.00 )");

conn.commit()
print("Records created successfully");
conn.close()

當執行上述程序時，它將在COMPANY表中創建/插入給定的記錄，並顯示以下兩行：

Opened database successfully
Records created successfully

SELECT操作

以下 Python 程序顯示了如何從上述示例中創建的 COMPANY 表中獲取和顯示記錄：

#!/usr/bin/python

import psycopg2

conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")
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[0])
   print("NAME = ", row[1])
   print("ADDRESS = ", row[2])
   print("SALARY = ", row[3], "\n")

print("Operation done successfully");
conn.close()

執行上述程序時，會產生以下結果：

Opened database successfully
ID =  1
NAME =  Paul
ADDRESS =  California
SALARY =  20000.0

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

更新操作

以下 Python 代碼顯示了如何使用UPDATE語句來更新任何記錄，然後從COMPANY表中獲取並顯示更新的記錄：

#!/usr/bin/python

import psycopg2

conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")
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[0])
   print("NAME = ", row[1])
   print("ADDRESS = ", row[2])
   print("SALARY = ", row[3], "\n")

print("Operation done successfully");
conn.close()

執行上述程序時，會產生以下結果：

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

刪除操作

以下 Python 代碼顯示了如何使用 DELETE 語句來刪除記錄，然後從 COMPANY 表中獲取並顯示剩余的記錄：

#!/usr/bin/python

import psycopg2

conn = psycopg2.connect(database="testdb", user="postgres", password="pass123", host="127.0.0.1", port="5432")
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[0])
   print("NAME = ", row[1])
   print("ADDRESS = ", row[2])
   print("SALARY = ", row[3], "\n")

print("Operation done successfully");
conn.close()

執行上述程序時，會產生以下結果：

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

Python 操作 PostgreSQL 數據庫