CX_ORACLE DOCUMENTATION PDF

This avoids connection storms which can decrease throughput. Pooled connections will retain their session state after they have been released back to the pool. However, because pools can grow, or connections in the pool can be recreated, there is no guarantee a subsequent acquire call will return a database connection that has any particular state. The SessionPool parameter sessionCallback enables efficient setting of session state so that connections have a known session state, without requiring that state to be explicitly set after each acquire call. Connections can also be tagged when they are released back to the pool. The tag is a user-defined string that represents the session state of the connection.

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If the column is unconstrained no precision and scale specified , the value will be returned as a float or an int depending on whether the value itself is an integer. In all other cases the value is returned as a float. Note that in Python 2, values returned as integers will be int or long depending on the size of the integer. In such cases, an output type handler can be specified for queries. Output type handlers do not affect values returned from Cursor.

Output type handlers can be specified on the connection or on the cursor. If specified on the cursor, fetch type handling is only changed on that particular cursor. If specified on the connection, all cursors created by that connection will have their fetch type handling changed.

The output type handler is expected to be a function with the following signature: handler cursor, name, defaultType, size, precision, scale The parameters are the same information as the query column metadata found in Cursor. The function is called once for each column that is going to be fetched. The function is expected to return a variable object generally by a call to Cursor.

The value None indicates that the default type should be used. Oracle Database uses decimal numbers and these cannot be converted seamlessly to binary number representations like Python floats. In addition, the range of Oracle numbers exceeds that of floating point numbers. Decimal converter gets called with the string representation of the Oracle number.

The output from decimal. Decimal is returned in the output tuple. The result set is cached on the database server until the cursor is closed. In contrast, regular cursors are restricted to moving forward. The method Cursor.

Each item is represented as a Python object corresponding to the Oracle Database object. This Python object can be traversed to access its elements. Attributes including ObjectType. For fetching of all data in consecutive small sets for batch processing. This happens because the number of records is too large for Python to handle at one time. The latter can be handled by calling Cursor. Since the query may be executed more than once, make sure to use bind variables for row numbers and row limits.

Be very careful to avoid SQL injection security issues. For Oracle Database 11g and earlier there are several alternative ways to limit the number of rows returned.

Review the client and database character sets. Do this by creating an outputtypehandler and setting encodingErrors. See Using Bind Variables instead. See Transaction Management for best practices on committing and rolling back data changes.

When handling multiple data values, use executemany for performance. If this is not the desired type, you can explicitly set it.

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Oracle Database for Python Developers, Part 1: cx_Oracle Quick Start

Oracle client libraries. These can be from the free Oracle Instant Client , or those included in Oracle Database if Python is on the same machine as the database. Oracle client libraries versions 19, 18, 12, and Users have also reported success with other platforms.

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cx_Oracle version 7.3

Currently 2, which means that threads may share the module and connections, but not cursors. Sharing means that a thread may use a resource without wrapping it using a mutex semaphore to implement resource locking. Note that in order to make use of multiple threads in a program which intends to connect and disconnect in different threads, the threaded parameter to connect or SessionPool must be true. They are possible values for the deliverymode attribute of the dequeue options object passed as the options parameter to the Connection. They are also possible values for the deliverymode attribute of the message properties object passed as the msgproperties parameter to the Connection. This is the default value. They are possible values for the mode attribute of the dequeue options object.

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Easily installed from PyPI. Support for Python 2 and 3. Support for Oracle Client Connect to Oracle Database 9.

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If the column is unconstrained no precision and scale specified , the value will be returned as a float or an int depending on whether the value itself is an integer. In all other cases the value is returned as a float. Note that in Python 2, values returned as integers will be int or long depending on the size of the integer. In such cases, an output type handler can be specified for queries. Output type handlers do not affect values returned from Cursor.

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