吳裕雄--天生天然 PYTHON3開發學習：MySQL - mysql-connector 驅動

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",       # 數據庫主機地址
  user="yourusername",    # 數據庫用戶名
  passwd="yourpassword"   # 數據庫密碼
)
 
print(mydb)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456"
)
 
mycursor = mydb.cursor()
 
mycursor.execute("CREATE DATABASE runoob_db")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456"
)
 
mycursor = mydb.cursor()
 
mycursor.execute("SHOW DATABASES")
 
for x in mycursor:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("CREATE TABLE sites (name VARCHAR(255), url VARCHAR(255))")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SHOW TABLES")
 
for x in mycursor:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("ALTER TABLE sites ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("CREATE TABLE sites (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), url VARCHAR(255))")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = ("RUNOOB", "https://www.runoob.com")
mycursor.execute(sql, val)
 
mydb.commit()    # 數據表內容有更新，必須使用到該語句
 
print(mycursor.rowcount, "記錄插入成功。")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = [
  ('Google', 'https://www.google.com'),
  ('Github', 'https://www.github.com'),
  ('Taobao', 'https://www.taobao.com'),
  ('stackoverflow', 'https://www.stackoverflow.com/')
]
 
mycursor.executemany(sql, val)
 
mydb.commit()    # 數據表內容有更新，必須使用到該語句
 
print(mycursor.rowcount, "記錄插入成功。")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = ("Zhihu", "https://www.zhihu.com")
mycursor.execute(sql, val)
 
mydb.commit()
 
print("1 條記錄已插入, ID:", mycursor.lastrowid)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites")
 
myresult = mycursor.fetchall()     # fetchall() 獲取全部記錄
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT name, url FROM sites")
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites")
 
myresult = mycursor.fetchone()
 
print(myresult)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE name ='RUNOOB'"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE url LIKE '%oo%'"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE name = %s"
na = ("RUNOOB", )
 
mycursor.execute(sql, na)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites ORDER BY name"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites ORDER BY name DESC"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites LIMIT 3")
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

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 Python3 CGI編程 Python3 MySQL 數據庫鏈接 – PyMySQL 驅動 
Python MySQL - mysql-connector 驅動
MySQL 是最流行的關係型數據庫管理系統，若是你不不熟悉 MySQL，能夠閱讀咱們的 MySQL 教程。

本章節咱們爲你們介紹使用 mysql-connector 來鏈接使用 MySQL， mysql-connector 是 MySQL 官方提供的驅動器。

咱們能夠使用 pip 命令來安裝 mysql-connector：

python -m pip install mysql-connector
使用如下代碼測試 mysql-connector 是否安裝成功：

demo_mysql_test.py:
import mysql.connector
執行以上代碼，若是沒有產生錯誤，代表安裝成功。

建立數據庫鏈接
能夠使用如下代碼來鏈接數據庫：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",       # 數據庫主機地址
  user="yourusername",    # 數據庫用戶名
  passwd="yourpassword"   # 數據庫密碼
)
 
print(mydb)
建立數據庫
建立數據庫使用 "CREATE DATABASE" 語句，如下建立一個名爲 runoob_db 的數據庫：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456"
)
 
mycursor = mydb.cursor()
 
mycursor.execute("CREATE DATABASE runoob_db")
建立數據庫前咱們也能夠使用 "SHOW DATABASES" 語句來查看數據庫是否存在：

demo_mysql_test.py:
輸出全部數據庫列表：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456"
)
 
mycursor = mydb.cursor()
 
mycursor.execute("SHOW DATABASES")
 
for x in mycursor:
  print(x)
或者咱們能夠直接鏈接數據庫，若是數據庫不存在，會輸出錯誤信息：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
建立數據表
建立數據表使用 "CREATE TABLE" 語句，建立數據表前，須要確保數據庫已存在，如下建立一個名爲 sites 的數據表：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("CREATE TABLE sites (name VARCHAR(255), url VARCHAR(255))")
執行成功後，咱們能夠看到數據庫建立的數據表 sites，字段爲 name 和 url。


咱們也能夠使用 "SHOW TABLES" 語句來查看數據表是否已存在：
demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SHOW TABLES")
 
for x in mycursor:
  print(x)
主鍵設置
建立表的時候咱們通常都會設置一個主鍵（PRIMARY KEY），咱們能夠使用 "INT AUTO_INCREMENT PRIMARY KEY" 語句來建立一個主鍵，主鍵起始值爲 1，逐步遞增。

若是咱們的表已經建立，咱們須要使用 ALTER TABLE 來給表添加主鍵：

demo_mysql_test.py:
給 sites 表添加主鍵。

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("ALTER TABLE sites ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY")
若是你還未建立 sites 表，能夠直接使用如下代碼建立。

demo_mysql_test.py:
給表建立主鍵。

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("CREATE TABLE sites (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), url VARCHAR(255))")
插入數據
插入數據使用 "INSERT INTO" 語句：

demo_mysql_test.py:
向 sites 表插入一條記錄。

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = ("RUNOOB", "https://www.runoob.com")
mycursor.execute(sql, val)
 
mydb.commit()    # 數據表內容有更新，必須使用到該語句
 
print(mycursor.rowcount, "記錄插入成功。")
執行代碼，輸出結果爲：

1 記錄插入成功
批量插入
批量插入使用 executemany() 方法，該方法的第二個參數是一個元組列表，包含了咱們要插入的數據：

demo_mysql_test.py:
向 sites 表插入多條記錄。

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = [
  ('Google', 'https://www.google.com'),
  ('Github', 'https://www.github.com'),
  ('Taobao', 'https://www.taobao.com'),
  ('stackoverflow', 'https://www.stackoverflow.com/')
]
 
mycursor.executemany(sql, val)
 
mydb.commit()    # 數據表內容有更新，必須使用到該語句
 
print(mycursor.rowcount, "記錄插入成功。")
執行代碼，輸出結果爲：

4 記錄插入成功。
執行以上代碼後，咱們能夠看看數據表的記錄：



若是咱們想在數據記錄插入後，獲取該記錄的 ID ，能夠使用如下代碼：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
val = ("Zhihu", "https://www.zhihu.com")
mycursor.execute(sql, val)
 
mydb.commit()
 
print("1 條記錄已插入, ID:", mycursor.lastrowid)
執行代碼，輸出結果爲：

1 條記錄已插入, ID: 6
查詢數據
查詢數據使用 SELECT 語句：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites")
 
myresult = mycursor.fetchall()     # fetchall() 獲取全部記錄
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')
(4, 'Taobao', 'https://www.taobao.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(6, 'Zhihu', 'https://www.zhihu.com')
也能夠讀取指定的字段數據：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT name, url FROM sites")
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

('RUNOOB', 'https://www.runoob.com')
('Google', 'https://www.google.com')
('Github', 'https://www.github.com')
('Taobao', 'https://www.taobao.com')
('stackoverflow', 'https://www.stackoverflow.com/')
('Zhihu', 'https://www.zhihu.com')
若是咱們只想讀取一條數據，能夠使用 fetchone() 方法：

demo_mysql_test.py:
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites")
 
myresult = mycursor.fetchone()
 
print(myresult)
執行代碼，輸出結果爲：

(1, 'RUNOOB', 'https://www.runoob.com')
where 條件語句
若是咱們要讀取指定條件的數據，能夠使用 where 語句：

demo_mysql_test.py
讀取 name 字段爲 RUNOOB 的記錄：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE name ='RUNOOB'"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(1, 'RUNOOB', 'https://www.runoob.com')
也能夠使用通配符 %：

demo_mysql_test.py
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE url LIKE '%oo%'"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
爲了防止數據庫查詢發生 SQL 注入的攻擊，咱們能夠使用 %s 佔位符來轉義查詢的條件：

demo_mysql_test.py
import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites WHERE name = %s"
na = ("RUNOOB", )
 
mycursor.execute(sql, na)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
排序
查詢結果排序能夠使用 ORDER BY 語句，默認的排序方式爲升序，關鍵字爲 ASC，若是要設置降序排序，能夠設置關鍵字 DESC。

demo_mysql_test.py
按 name 字段字母的升序排序：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites ORDER BY name"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(3, 'Github', 'https://www.github.com')
(2, 'Google', 'https://www.google.com')
(1, 'RUNOOB', 'https://www.runoob.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(4, 'Taobao', 'https://www.taobao.com')
(6, 'Zhihu', 'https://www.zhihu.com')
降序排序實例：

demo_mysql_test.py
按 name 字段字母的降序排序：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "SELECT * FROM sites ORDER BY name DESC"
 
mycursor.execute(sql)
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(6, 'Zhihu', 'https://www.zhihu.com')
(4, 'Taobao', 'https://www.taobao.com')
(5, 'stackoverflow', 'https://www.stackoverflow.com/')
(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')
Limit
若是咱們要設置查詢的數據量，能夠經過 "LIMIT" 語句來指定

demo_mysql_test.py
讀取前 3 條記錄：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites LIMIT 3")
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)
執行代碼，輸出結果爲：

(1, 'RUNOOB', 'https://www.runoob.com')
(2, 'Google', 'https://www.google.com')
(3, 'Github', 'https://www.github.com')
也能夠指定起始位置，使用的關鍵字是 OFFSET：

demo_mysql_test.py
從第二條開始讀取前 3 條記錄：

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
mycursor.execute("SELECT * FROM sites LIMIT 3 OFFSET 1")  # 0 爲 第一條，1 爲第二條，以此類推
 
myresult = mycursor.fetchall()
 
for x in myresult:
  print(x)

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "DELETE FROM sites WHERE name = 'stackoverflow'"
 
mycursor.execute(sql)
 
mydb.commit()
 
print(mycursor.rowcount, " 條記錄刪除")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "DELETE FROM sites WHERE name = %s"
na = ("stackoverflow", )
 
mycursor.execute(sql, na)
 
mydb.commit()
 
print(mycursor.rowcount, " 條記錄刪除")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "UPDATE sites SET name = 'ZH' WHERE name = 'Zhihu'"
 
mycursor.execute(sql)
 
mydb.commit()
 
print(mycursor.rowcount, " 條記錄被修改")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "UPDATE sites SET name = %s WHERE name = %s"
val = ("Zhihu", "ZH")
 
mycursor.execute(sql, val)
 
mydb.commit()
 
print(mycursor.rowcount, " 條記錄被修改")

import mysql.connector
 
mydb = mysql.connector.connect(
  host="localhost",
  user="root",
  passwd="123456",
  database="runoob_db"
)
mycursor = mydb.cursor()
 
sql = "DROP TABLE IF EXISTS sites"  # 刪除數據表 sites
 
mycursor.execute(sql)