Common problems and solutions for installing cx_Oracle module in python

The examples in this article describe common problems and solutions for installing the cx_Oracle module in Python. Share it with everyone for your reference, the details are as follows:

When installing or using cx_Oracle, you need to use the Oracle link library, such as libclntsh.so.10.1, otherwise there will be various error messages .

You can get this link library by installing Oracle Instant Client, avoiding the installation of hundreds of megabytes of Oracle Client.

Software download address:

cx_Oracle’s homepage: http://cx-oracle.sourceforge.net/

Download address of required Oracle link library: http://www.oracle.com/technology/software/tech/oci/instantclient/index.html

Common errors and solutions:

1.Win32 binary installation

In Windows After installing cx_Oracle-5.0-10g.win32-py2.6.msi, when importing, an error of DLL loading failure is reported, as follows:

IDLE 2.6.1

>>> import cx_Oracle
Traceback (most recent call last):
 File "<pyshell#0>", line 1, in <module>
  import cx_Oracle
ImportError: DLL load failed: 找不到指定的程序。

Solution:

Download instantclient-basic-win32-10.2.0.4.zip from the Oracle site, unzip it, and copy the oci.dll file Go to Lib/site-packages in the Python installation directory, such as C:/Python26/Lib/site-packages

2. Binary installation under Linux

Under linux_x86_64, an error is reported when installing cx_Oracle-5.0.1-10g-py24-1.x86_64.rpm.

[root@BJ-UPDATE-01 ~]# rpm -ivh cx_Oracle-5.0.1-10g-py24-1.x86_64.rpm
error: Failed dependencies:
    libclntsh.so.10.1()(64bit) is needed by cx_Oracle-5.0.1-1.x86_64

Solution:

Reference http://www.php.cn/

Download basic-10.2.0.4.0-linux-x86_64.zip from the Oracle site to the /opt directory and unzip it. You will see that libclntsh.so.10.1 is set in the /opt/instantclient_10_2 directory

Environment variable

vi /root/.bash_profile

Add the following two lines:

export ORACLE_HOME=/opt/instantclient_10_2
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$ORACLE_HOME

Run source /root/.bash_profile Make changes take effect

Create a symbolic link to this link library

cd $ORACLE_HOME
ln -s libclntsh.so.x.x libclntsh.so

Restart Install cx_Oracle

Be careful to add the --nodeps parameter, otherwise the above error will be reported

[root@BJ-UPDATE-01 ~]# rpm -ivh --nodeps cx_Oracle-5.0.1-10g-py24-1.x86_64.rpm
#5.0.3版本不用加--nodeps参数

三.Source code installation under linux

Set environment variables and symbolic links as above. To install source code under linux_x86_64, run python setup.py build. The error message during compilation is as follows:

Connection.c:1169: warning: statement does not work
Connection.c:1171: error: 'udt_Connection' has no member named 'environment'
Connection.c:1172: warning: passing parameter 1 Converting between incompatible pointer types when passing argument 2 (of 'Environment_CheckForError')
Connection.c:1172: warning: Converting between incompatible pointer types when passing argument 2 (of 'Environment_CheckForError')
Connection.c :1172: Error: Too many arguments supplied to function 'Environment_CheckForError'
Connection.c:1176: Error: 'udt_Connection' has no member named 'sessionHandle'

Solution:

This error does not occur in version 5.0.3. Please note that there must be an include directory under ORACLE_HOME. This directory must contain the source files required for compilation. The source files are not available in the Oracle Instant Client. Include. I copied it from the directory D:/oracle/product/10.2.0/client_1/oci/include on the Windows client.

4.Import error

>>> import cx_Oracle
Traceback (most recent call last):
 File "<stdin>", line 1, in ?
ImportError: /usr/lib/oracle/10.2.0.4/client64//lib/libnnz10.so: cannot restore segment prot after reloc: Permission denied
>>> import cx_Oracle
Traceback (most recent call last):
 File "<stdin>", line 1, in ?
ImportError: /usr/lib/oracle/10.2.0.4/client64//lib/libclntsh.so.10.1: cannot restore segment prot after reloc: Permission denied
>>> import cx_Oracle
>>>

This is because of the limitations of SELinux, run as follows Command to cancel the restriction:

chcon -t texrel_shlib_t cd $ORACLE_HOME/libnnz10.so
chcon -t texrel_shlib_t cd $ORACLE_HOME/libclntsh.so.10.1

5. Runtime error

##

Traceback (most recent call last):
 File "oracle_conn.py", line 9, in ?
  connection = cx_Oracle.Connection(u"oracle/oracle123@CCIP")
cx_Oracle.InterfaceError: Unable to acquire Oracle environment handle

It is still a limitation of SELinux, set SELinux to disabled

Turn off selinux:

Run the command: vim /etc/selinux/config

Change selinux=enforcing or permissive to disabled
Run the command: setenforce 0

6. There is a problem with the UNICODE installation package

Traceback (most recent call last):
 File "./oracle_conn.py", line 22, in ?
  folderIds=cursor.fetchmany(10)
cx_Oracle.DatabaseError: OCI-22061: Message 22061 not found; No message file for product=RDBMS, facility=OCI; arguments: [T

It is currently found that the 5.0.3 version of the package will cause an error when executing SQL. It is not recommended to use it. If you replace it with a non-UNICODE package, there will be no problem.

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