Python 操做 MySQL 的正確姿式
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做者 |邵建永
編輯 | 顧鄉css
使用Python進行MySQL的庫主要有三個，Python-MySQL（更熟悉的名字多是MySQLdb），PyMySQL和SQLAlchemy。html
Python-MySQL資格最老，核心由C語言打造，接口精煉，性能最棒，缺點是環境依賴較多，安裝複雜，近兩年已中止更新，只支持Python2，不支持Python3。java
PyMySQL爲替代Python-MySQL而生，純python打造，接口與Python-MySQL兼容，安裝方便，支持Python3。python
SQLAlchemy是一個ORM框架，它並不提供底層的數據庫操做，而是要藉助於MySQLdb、PyMySQL等第三方庫來完成，目前SQLAlchemy在Web編程領域應用普遍。mysql
本文主要介紹PyMySQL的正確使用方法，示例代碼都是選自實戰項目。git
安裝
簡單的方式：程序員
pip install pymysql
若是沒法聯網，須要進行離線安裝，例如：sql
pip install pymysql-x.x.x.tar.gz
導入
import pymysql
鏈接
def connect_wxremit_db():
return pymysql.connect(host='10.123.5.28',
port=3306,
user='root',
password='root1234',
database='db_name',
charset='latin1')
查詢
def query_country_name(cc2):
sql_str = ("SELECT Fcountry_name_zh"
+ " FROM t_country_code"
+ " WHERE Fcountry_2code='%s'" % (cc2))
logging.info(sql_str)
con = mysql_api.connect_wxremit_db()
cur = con.cursor()
cur.<span class="hljs-built_in">execute</span>(sql_str)
rows = cur.fetchall()
cur.<span class="hljs-built_in">close</span>()
con.<span class="hljs-built_in">close</span>()
<span class="hljs-built_in">assert</span> <span class="hljs-built_in">len</span>(rows) == <span class="hljs-number">1</span>, <span class="hljs-string">'Fatal error: country_code does not exists!'</span>
<span class="hljs-keyword">return</span> rows[<span class="hljs-number">0</span>][<span class="hljs-number">0</span>]
con = mysql_api.connect_wxremit_db()
cur = con.cursor()
cur.<span class="hljs-built_in">execute</span>(sql_str)
rows = cur.fetchall()
cur.<span class="hljs-built_in">close</span>()
con.<span class="hljs-built_in">close</span>()
<span class="hljs-built_in">assert</span> <span class="hljs-built_in">len</span>(rows) == <span class="hljs-number">1</span>, <span class="hljs-string">'Fatal error: country_code does not exists!'</span>
<span class="hljs-keyword">return</span> rows[<span class="hljs-number">0</span>][<span class="hljs-number">0</span>]
簡單插入
def insert_file_rec(self, file_name, file_md5):
con = mysql_api.connect_wxremit_db()
cur = con.cursor()
try:
sql_str = ("INSERT INTO t_forward_file (Ffile_name, Ffile_md5)",
+ " VALUES ('%s', '%s')" % (file_name, file_md5))
cur.execute(sql_str)
con.commit()
except:
con.rollback()
logging.exception('Insert operation error')
raise
finally:
cur.close()
con.close()
批量插入
數據庫
remit_ids = [('1234', 'CAD'), ('5678', 'HKD')]con = mysql_api.connect_wxremit_db()
cur = con.cursor()
try:
cur.executemany("INSERT INTO t_order (Fremit_id, Fcur_type, Fcreate_time"
+ " VALUES (%s, %s, now())", new_items)
assert cur.rowcount == len(remit_ids), 'my error message'
con.commit()
except Exception as e:
con.rollback()
logging.exception('Insert operation error')
finally:
cur.close()
con.close()
更新
def update_refund_trans(self, remit_id):
con = mysql_api.connect_wxremit_db()
cur = con.cursor()
try:
sql_str = ("SELECT Fremit_id"
+ " FROM t_wxrefund_trans"
+ " WHERE Fremit_id='%s'" % remit_id
+ " FOR UPDATE")
logging.info(sql_str)
cur.execute(sql_str)
<span class="hljs-keyword">assert</span> cur.rowcount == <span class="hljs-number">1</span>, <span class="hljs-string">'Fatal error: The wx-refund record be deleted!'</span>
sql_str = (<span class="hljs-string">"UPDATE t_wxrefund_trans"</span>
+ <span class="hljs-string">" SET Fcheck_amount_flag=1"</span>
+ <span class="hljs-string">", Fmodify_time=now()"</span>
+ <span class="hljs-string">" WHERE Fremit_id='%s'"</span> % remit_id
logging.info(sql_str)
cur.execute(sql_str)
<span class="hljs-keyword">assert</span> cur.rowcount == <span class="hljs-number">1</span>, <span class="hljs-string">'The number of affected rows not equal to 1'</span>
con.commit()
<span class="hljs-keyword">except</span>:
con.rollback()
logging.exception(<span class="hljs-string">'Update operation error'</span>)
<span class="hljs-keyword">raise</span>
<span class="hljs-keyword">finally</span>:
cur.close()
con.close()
cur.execute(sql_str)
<span class="hljs-keyword">assert</span> cur.rowcount == <span class="hljs-number">1</span>, <span class="hljs-string">'Fatal error: The wx-refund record be deleted!'</span>
sql_str = (<span class="hljs-string">"UPDATE t_wxrefund_trans"</span>
+ <span class="hljs-string">" SET Fcheck_amount_flag=1"</span>
+ <span class="hljs-string">", Fmodify_time=now()"</span>
+ <span class="hljs-string">" WHERE Fremit_id='%s'"</span> % remit_id
logging.info(sql_str)
cur.execute(sql_str)
<span class="hljs-keyword">assert</span> cur.rowcount == <span class="hljs-number">1</span>, <span class="hljs-string">'The number of affected rows not equal to 1'</span>
con.commit()
<span class="hljs-keyword">except</span>:
con.rollback()
logging.exception(<span class="hljs-string">'Update operation error'</span>)
<span class="hljs-keyword">raise</span>
<span class="hljs-keyword">finally</span>:
cur.close()
con.close()
PyMySQL已經至關成熟，和Python-MySQL同樣，它在不少Linux發行版本中都是可選的安裝組件。
</div> <div class="postDesc">posted @ <span id="post-date">2017-04-25 21:26</span> <a href="https://www.cnblogs.com/liuliliuli2017/">琉璃塊</a> 閱讀(<span id="post_view_count">12782</span>) 評論(<span id="post_comment_count">0</span>) <a href="https://i.cnblogs.com/EditPosts.aspx?postid=6763988" rel="nofollow">編輯</a> <a href="#" onclick="AddToWz(6763988);return false;">收藏</a></div> </div>