python连接数据库

记录几种常见的python连接数据库的代码，方便用的时候直接取。

1.python连接mysql

import pymysql
import pprint
#
# HOST = '127.0.0.1'
# PORT = 3306
# USER = 'root'
# PASSWD = 'root'
# dbName = 'mysql'

def conn_mysql(host,port,user,passwd,dbname):
    conn = pymysql.connect(host=host,
                           port=port,
                           user=user,
                           passwd=passwd,
                           db=dbname,
                           charset='utf8')
    cursor = conn.cursor()

    # def show_tables():
    sql = 'show tables;'
    cursor.execute(sql)
    rowList = cursor.fetchall()
    tableList = list()
    for row in rowList:
        tableList.append(row[0])
    print('tableList(%d):\n%s\n' % (len(tableList), pprint.pformat(tableList, indent=4)))
    # return tableList

2.python连接hive

from pyhive import hive
import pandas as pd
ip=''
conn = hive.connect(ip)
def runhql(sql):
    cursor = conn.cursor()
    cursor.execute(sql)
    logs = cursor.fetch_logs()
    datas = cursor.fetchall()
    print(len(datas))
    return datas

3.python连接德鲁伊库

from pydruid.db import connect
def find_druid(ip,port,sql):  
    conn = connect(host=ip, port=port)  
    curs = conn.cursor()
    curs.execute(sql)
    df = pd.DataFrame(curs.fetchall())
    return df

4.python连接sqlsever

import pymssql
import pprint

def conn_sqlserver(host,port,user,password,database):
    port = str(port)
    host = host+':'+port
    connect = pymssql.connect(host=host, user=user, password=password,
                              database=database, charset='utf8')
    if connect:
        print("连接成功!")
    cursor = connect.cursor()  # 创建一个游标对象,python里的sql语句都要通过cursor来执行
    cursor.execute("select name from sysobjects where xtype='U'")  # 执行sql语句,获取数据库中的表名
    rowList = cursor.fetchall()
    tableList = []
    for row in rowList:
        tableList.append(row[0])
    print('tableList(%d):\n%s\n' % (len(tableList), pprint.pformat(tableList, indent=4)))

    # 处理每个表
    for tabName in tableList:
        print('table %s ...' % tabName)
        sql = "select name from syscolumns where id = object_id('%s')"
        sql = sql % (tabName)
        cursor.execute(sql)
        rowList = cursor.fetchall()
        fieldList = list()
        for row in rowList:
            fieldList.append(row[0])
        print('fieldList(%d):\n%s\n' % (len(fieldList), pprint.pformat(fieldList, indent=4)))
    cursor.close()  # 关闭游标
    connect.close()  # 关闭连接

5.python连接oracle

import cx_Oracle
import pprint

def conn_oracle(host,port,user,passwd,dbname,sql):
    port = str(port)
    host_port = user+'/'+passwd+'@'+host+':'+port+'/'+dbname
    conn = cx_Oracle.connect("%s" %host_port)
    cursor = conn.cursor()

    # 获取当前用户下的所有表的信息
    # def conn_oracle():
    results = cursor.execute(sql)
    # 获取所有数据
    all_data = cursor.fetchall()
    tabList = []
    for data in all_data:
        tabList.append(data[0])
    print('tabList(%d):\n%s\n' % (len(tabList), pprint.pformat(tabList, indent=4)))

    # 处理每个表
    for tabName in tabList:
        print('table %s ...' % tabName)
        sql = 'select * from "%s" '
        sql = sql % (tabName)
        cursor.execute(sql)
        rowList = cursor.fetchall()
        title = [i[0] for i in cursor.description]
        print(title)
        # fieldList = list()
        # for row in rowList:
        #     fieldList.append(row[0])
        # print('fieldList(%d):\n%s\n' % (len(fieldList), pprint.pformat(fieldList, indent=4)))
    cursor.close()
    conn.close()

6.python 连接impala查询：

from impala.dbapi import connect
ip=''
port=''
sql=''
conn = connect(host=ip, port=port)
cur = conn.cursor()
cur.execute(sql)
data_list=cur.fetchall()
for data in data_list:
   print data