[cx-oracle-users] How to use module in a class

[Andrew Z. <fo...@gm...>]

Hello,
 i'm trying to use the module within a designated "Database" class and
having all sorts of funny situations.
 I'd appreciate some guidance on how to architecture the interaction in a
better way.

Task:
 I'd like to separate all database related operations into one class (
let's call it DB).

for example:

import cx_Oracle
import decimal

class DB():
   DEFAULT_DB = '127.0.0.1/TT_1122:timesten:direct'
   DEFAULT_DB_USER = "username"
   DEFAULT_DB_USER_PASSWD = "password"

   def __init__(self, db = None, user = None, passw = None):
      if db is None:
         db = self.DEFAULT_DB
      if user is None:
         user = self.DEFAULT_DB_USER
      if passw is None:
         passw = self.DEFAULT_DB_USER_PASSWD

      self.connection = cx_Oracle.Connection(user + "/" + passw + "@"
+ self.DEFAULT_DB)
      self.connection.outputtypehandler = self.OutputTypeHandler

   def OutputTypeHandler(cursor, name, defaultType, size, precision, scale):
      if defaultType == cx_Oralce.NUMBER:
         return cursor.var(str, size=200, arraysize=Cursor.arraysize,
                           outconverter=decimal.Decimal)

   def close(self, commit=True):
      """Close connection"""
      if commit:
         self.connection.commit()
      self.connection.close()

def checkData(self, minutes):

   cursor = self.connection.cursor()
   cursor.execute("select sum(reqid) from movaver")
   rows = cursor.fetchone()
   cursor.close()
   if rows is None:
      raise Exception("No rows returned during checkData({})".format(minutes))
   return rows[0]


There are a few issues with this approach. For instance the "var" and
"arraysize" in cursor ( function OutputTypeHandler" are not been resolved
as attributes of "cursor"

though, if i do not try to wrap this functionality in the class and just
simply import the cx_Oracle and start writing the functions - everything
gets resolved as expected.


My other attempt was to import Connection, Cursor etc from cx_Oracle and
define DB as a child of many parents... This is how i learned that python
doesn't support such arrangements.

Appreciate your advice.