Simple methods and encapsulated class examples for operating Oracle database in Python

conn=cx_Oracle.connect('用户名','密码','数据库地址:数据库端口/SID')

conn=cx_Oracle.connect('用户名/密码@数据库地址:数据库端口/SID')

conn=cx_Oracle.connect('用户名','密码',tns)

tns=cx_Oracle.makedsn('数据库地址','数据库端口', 'SID')

tns = '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=127.0.0.1)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=KGDB)))'

conn = cx_Oracle.connect('nicker', '123456', tns)

#coding:utf-8

import cx_Oracle

# 创建数据库连接

# cx_Oracle.connect('username','pwd','ora的tns信息')

# oracle数据库的tns信息，从tnsnames.ora中找到plsql可用的配置项，将该配置项直接拷贝过来即可

ora_tns = '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=127.0.0.1)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=KGDB)))'

conn = cx_Oracle.connect('nicker', '123456', ora_tns)

# 操作游标

cursor = conn.cursor()

# 执行查询

cursor.execute("SELECT * FROM inst_info")

# 获取返回信息

rs = cursor.fetchall()

# 输出信息

for v in rs:

  print v

#关闭连接，释放资源

cursor.close()

conn.close()

#coding:utf-8

import cx_Oracle

# 封装的类

class cxOracle:

  '''

  tns的取值tnsnames.ora对应的配置项的值，如：

  tns = '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.16.18.23)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=MYDB)))'

  '''

  def __init__(self ,uname, upwd,tns ):

    self ._uname = uname

    self ._upwd = upwd

    self ._tns = tns

    self ._conn = None

    self ._ReConnect()

  def _ReConnect(self ):

    if not self._conn :

      self ._conn = cx_Oracle.connect (self. _uname, self ._upwd, self._tns)

    else:

      pass

  def __del__(self ):

    if self. _conn:

      self ._conn. close()

      self ._conn = None

  def _NewCursor(self ):

    cur = self. _conn.cursor ()

    if cur:

      return cur

    else:

      print "#Error# Get New Cursor Failed."

      return None

  def _DelCursor(self , cur):

    if cur:

      cur .close()

  # 检查是否允许执行的sql语句

  def _PermitedUpdateSql(self ,sql):

    rt = True

    lrsql = sql. lower()

    sql_elems = [ lrsql.strip ().split()]

    # update和delete最少有四个单词项

    if len( sql_elems) < 4 :

      rt = False

    # 更新删除语句，判断首单词，不带where语句的sql不予执行

    elif sql_elems[0] in [ 'update', 'delete']:

      if 'where' not in sql_elems :

        rt = False

    return rt

  # 导出结果为文件

  def Export(self , sql, file_name, colfg ='||'):

    rt = self. Query(sql )

    if rt:

      with open( file_name, 'a') as fd:

        for row in rt:

          ln_info = ''

          for col in row:

             ln_info += str( col) + colfg

          ln_info += '\n'

          fd .write( ln_info)

  # 查询

  def Query(self , sql, nStart=0 , nNum=- 1):

    rt = []

    # 获取cursor

    cur = self. _NewCursor()

    if not cur:

      return rt

    # 查询到列表

    cur .execute(sql)

    if ( nStart==0 ) and (nNum==1 ):

      rt .append( cur.fetchone ())

    else:

      rs = cur. fetchall()

      if nNum==- 1:

        rt .extend( rs[nStart:])

      else:

        rt .extend( rs[nStart:nStart +nNum])

    # 释放cursor

    self ._DelCursor(cur)

    return rt

  # 更新

  def Exec(self ,sql):

    # 获取cursor

    rt = None

    cur = self. _NewCursor()

    if not cur:

      return rt

    # 判断sql是否允许其执行

    if not _PermitedUpdateSql(sql ):

      return rt

    # 执行语句

    rt = cur. execute(sql )

    # 释放cursor

    self ._DelCursor(cur)

    return rt

# 类使用示例

tns = '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.16.17.46)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=MYDB)))'

ora = cxOracle ('nicker', '123456', tns)

# 导出结果为文件

rs = ora .Export("SELECT * FROM org", '1.txt')

# 查询结果到列表

rs = ora.Query("SELECT * FROM org")

print rs

# 更新数据

ora.Exec("update org set org_name='NewNameForUpdate' where org_id=123456;")