Python 操做 MySQL

本文連接Python 操做 MySQL

開發環境與配置

• win_x64
• Ubuntu14.04
• Python3.x

pip安裝pymysql模塊

直接使用pip安裝 pip install pymysql
win64上直接在cmd中執行

鏈接本地數據庫

使用模塊pymysql鏈接數據庫
本地數據庫相關配置請參閱： rustfisher.github.io/2017/02/25/…

#!/usr/bin/python
# coding=utf-8
import pymysql

# 鏈接本地數據庫
conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='yourpwd', db='samp_db1', charset='utf8')
cursor = conn.cursor()
cursor.execute('select * from bigstu')
for row in cursor.fetchall():
    print(row)

# 查
cursor.execute('select id, name from bigstu where age > 22')
for res in cursor.fetchall():
    print(str(res[0]) + ", " + res[1])

cursor.close()
print('-- end --')
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輸出：

(1, '張三', '男', 24, datetime.date(2017, 3, 29), '13666665555')
(6, '小剛', '男', 23, datetime.date(2017, 3, 11), '778899888')
(8, '小霞', '女', 20, datetime.date(2017, 3, 13), '13712345678')
(12, '小智', '男', 21, datetime.date(2017, 3, 7), '13787654321')
1, 張三
6, 小剛
-- end --
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能夠直接執行sql語句。得到的結果是元組。

sql類似條件查詢

SELECT * FROM anindex.subject_basic_table where season_id having '2018';
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增

插入數據

插入一條數據，接上面的代碼

insertSql = "insert into bigstu (name, sex, age, mobile) values ('%s','%s',%d,'%s') "
xiuji = ('秀吉', '男', 15, '13400001111')
cursor.execute(insertSql % xiuji)
conn.commit() # 別忘了提交
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添加列

在mobile後面添加一列cash

addCo = "alter table bigstu add cash int after mobile"
cursor.execute(addCo)
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若是要設置默認值

addCo = "alter table bigstu add cash int default 0 after mobile"
cursor.execute(addCo)
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刪

刪除數據

刪除 name=秀吉 的數據

deleteSql = "delete from bigstu where name = '%s'"
cursor.execute(deleteSql % '秀吉')
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刪除列

刪除cash列

dropCo = "alter table bigstu drop cash"
cursor.execute(dropCo)
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改

修改數據

更新符合條件的數據

updateSql = "update bigstu set sex = '%s' where name = '%s'"
updateXiuji = ('秀吉', '秀吉') # 秀吉的性別是秀吉
cursor.execute(updateSql % updateXiuji)
conn.commit()
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事物處理

給某個記錄的cash增長

table = "bigstu"
addCash = "update " + table + " set cash = cash + '%d' where name = '%s'"
lucky = (1000, "秀吉")

try:
    cursor.execute(addCash % lucky)
except Exception as e:
    conn.rollback()
    print("加錢失敗了")
else:
    conn.commit()
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直接執行SQL語句，十分方便

代碼片斷

給數據庫添加列

從json中讀取須要添加的列名，獲取當前2個表中全部的列名
整理得出須要插入的列名，而後將列插入到相應的表中

import pymysql
import json
import os
import secureUtils

mapping_keys = json.load(open("key_mapping_db.json", "r"))
db_keys = []  # json中全部的key

for k in mapping_keys.values():
    db_keys.append(k)

conn = pymysql.connect(host='localhost', port=3306, user='root',
                       passwd='*****', db='db_name', charset='utf8')

cursor = conn.cursor()
table_main = "table_main"
main_table_keys = []  # 主表的列名
cursor.execute("show columns from " + table_main)
for row in cursor.fetchall():
    main_table_keys.append(row[0])

staff_table_keys = []
cursor.execute("show columns from table_second")
for row in cursor.fetchall():
    staff_table_keys.append(row[0])

need_to_insert_keys = []
for k in db_keys:
    if k not in staff_table_keys and k not in main_table_keys and k not in need_to_insert_keys:
        need_to_insert_keys.append(k)

print("need to insert " + str(len(need_to_insert_keys)))
print(need_to_insert_keys)
for kn in need_to_insert_keys:
    print("add key to db " + kn)
    cursor.execute("alter table staff_table add " + kn +" text")

conn.close()
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將字段字符改變

這裏將main_table_keys中的全部字段改成utf8

# change column character set to utf8
for co in main_table_keys:
    change_sql = "alter table " + table_main + " modify " + co + " text character set utf8"
    print(change_sql)
    cursor.execute(change_sql)
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