開發(fā)環(huán)境與配置

pip安裝pymysql模塊

直接使用pip安裝 pip install pymysqlwin64上直接在cmd中執(zhí)行

連接本地數(shù)據(jù)庫

使用模塊pymysql連接數(shù)據(jù)庫

本地數(shù)據(jù)庫相關配置請參閱： http://rustfisher.github.io/2017/02/25/backend/MySQL_install/

#!/usr/bin/python# coding=utf-8import pymysql# 連接本地數(shù)據(jù)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 --’)

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 --

可以直接執(zhí)行sql語句。獲得的結(jié)果是元組。

sql相似條件查詢

SELECT * FROM anindex.subject_basic_table where season_id having ’2018’;

增

插入數(shù)據(jù)

插入一條數(shù)據(jù)，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

添加列

在mobile后面添加一列cash

addCo = 'alter table bigstu add cash int after mobile'cursor.execute(addCo)

如果要設置默認值

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

刪

刪除數(shù)據(jù)

刪除 name=秀吉 的數(shù)據(jù)

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

刪除列

刪除cash列

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

改

修改數(shù)據(jù)

更新符合條件的數(shù)據(jù)

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()

事物處理

給某個記錄的cash增加

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()

直接執(zhí)行SQL語句，十分方便

代碼片段

給數(shù)據(jù)庫添加列

從json中讀取需要添加的列名，獲取當前2個表中所有的列名整理得出需要插入的列名，然后將列插入到相應的表中

import pymysqlimport jsonimport osimport secureUtilsmapping_keys = json.load(open('key_mapping_db.json', 'r'))db_keys = [] # json中所有的keyfor 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()

將字段字符改變

這里將main_table_keys中的所有字段改為utf8

# change column character set to utf8for 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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