57 lines
1.9 KiB
Python
57 lines
1.9 KiB
Python
#------------------------------------------------------------------------------
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# Copyright 2016, 2017, Oracle and/or its affiliates. All rights reserved.
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#------------------------------------------------------------------------------
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#------------------------------------------------------------------------------
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# Subclassing.py
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#
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# Demonstrate how to subclass cx_Oracle connections and cursors in order to
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# add additional functionality (like logging) or create specialized interfaces
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# for paticular applications.
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#------------------------------------------------------------------------------
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from __future__ import print_function
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import cx_Oracle
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import SampleEnv
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# sample subclassed connection which overrides the constructor (so no
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# parameters are required) and the cursor() method (so that the subclassed
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# cursor is returned instead of the default cursor implementation)
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class Connection(cx_Oracle.Connection):
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def __init__(self):
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connectString = SampleEnv.MAIN_CONNECT_STRING
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print("CONNECT to database")
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return super(Connection, self).__init__(connectString)
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def cursor(self):
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return Cursor(self)
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# sample subclassed cursor which overrides the execute() and fetchone()
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# methods in order to perform some simple logging
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class Cursor(cx_Oracle.Cursor):
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def execute(self, statement, args):
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print("EXECUTE", statement)
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print("ARGS:")
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for argIndex, arg in enumerate(args):
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print(" ", argIndex + 1, "=>", repr(arg))
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return super(Cursor, self).execute(statement, args)
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def fetchone(self):
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print("FETCH ONE")
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return super(Cursor, self).fetchone()
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# create instances of the subclassed connection and cursor
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connection = Connection()
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cursor = connection.cursor()
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# demonstrate that the subclassed connection and cursor are being used
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cursor.execute("select count(*) from ChildTable where ParentId = :1", (3,))
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count, = cursor.fetchone()
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print("COUNT:", int(count))
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