Thursday Jan 22, 2015

A Personal Victory: Oracle Database Sample Schemas are on GitHub

For anyone who ever deleted a row from a table in Oracle's Sample HR schema and wanted it back, help is nearby. You no longer have to download the full "Oracle Database 12c Release 1 Examples" zip (499,228,127 bytes worth for the Linux bundle) and run the Oracle installer. Now you can clone our GitHub db-sample-schema repository and run the creation SQL scripts in SQL*Plus.

This new repository installs these six sample schemas:

  • HR: Human Resources
  • OE: Order Entry
  • PM: Product Media
  • IX: Information Exchange
  • SH: Sales History
  • BI: Business Intelligence

Because of the widespread use of these schemas, we did minimal changes to the bundle. The install, as it is given, installs all schemas and needs to be done on a database server since file system access is needed from the database.

But now, if you want, you can fork the repo and modify it to install just the HR schema from a client machine. Or change your fork to install the HR schema into an arbitrary user name of your choice so multiple people can test the same data set. And what about modifying the script to do DROP TRIGGER SECURE_EMPLOYEES getting rid of that annoying time-based trigger which yells 'You may only make changes during normal office hours' if you try to make changes after 6pm or on weekends? This may be a great teaching tool about triggers but not useful when you are configuring demonstrations for big conferences late into the night!

And why is this a personal victory? Because as a client tool person, how to find these schema creation scripts has irked me in the past. The HR schema replaced SCOTT/TIGER in the Oracle documentation a long time ago but was not easily available to use. I've written a lot of examples using HR but never had a good way to instruct how to install the schema. I'm glad to have helped (being partially modest here about the legal and administrative things it required) getting this small set of scripts out on GitHub. If it makes it easier for someone to talk about features or issues by reference to a common data set, then my job is done. Having the scripts readily available is also a reminder to the Oracle community to share information and knowledge efficiently. Even as we head to a world of cloneable databases and snapshots, sometimes it is just easier to run a SQL script.

This repo is a piece of a jigsaw, and it can be used where it fits. The schemas could be now considered "traditional". In future, Oracle Database teams will continue to create fresh data sets to show off newer and upcoming database features, such as these analytical-sql-examples that you might be interested in.

Monday Nov 17, 2014

Configuring Python cx_Oracle and mod_wsgi on Oracle Linux

The Web Server Gateway Interface (WSGI) is a standardized interface between web servers and Python web frameworks or applications. Many frameworks including Django support WSGI.

This post is a brief how-to about configuring Apache's mod_wsgi with Python's cx_Oracle driver for Oracle Database. The steps are for Oracle Linux.

  1. Download Instant Client Basic & SDK ZIP files from OTN. For cx_Oracle 5.1, use the ZIPs, not the RPMs.

  2. As root, unzip the files to the same directory, e.g. /opt/oracle/instantclient_12_1:

    mkdir /opt/oracle
    cd /opt/oracle
    unzip /tmp/instantclient-basic-linux.x64-12.1.0.2.0.zip
    unzip /tmp/instantclient-sdk-linux.x64-12.1.0.2.0.zip
    
  3. Configure Instant Client:

    cd /opt/oracle/instantclient_12_1
    ln -s libclntsh.so.12.1 libclntsh.so
    
  4. Install the pip package management tool for Python by following pip.readthedocs.org/en/latest/installing.html and downloading get-pip.py. Then run:

    python get-pip.py
    
  5. Install cx_Oracle:

    export LD_RUN_PATH=/opt/oracle/instantclient_12_1
    export ORACLE_HOME=/opt/oracle/instantclient_12_1
    pip install cx_Oracle
    

    The key here is the use of LD_RUN_PATH. This obviates the need to later set LD_LIBRARY_PATH or configure ldconfig for cx_Oracle to find the Instant Client libraries. There is a cx_Oracle-specific variable FORCE_RPATH which has the same effect.

    Note the cx_Oracle installer overloads the meaning of ORACLE_HOME. This variable is not normally used with Instant Client.

    Neither ORACLE_HOME or LD_RUN_PATH need to be set at runtime.

    If you don't use LD_RUN_PATH or FORCE_RPATH during installation, you will need to make LD_LIBRARY_PATH available to the Apache process or use ldconfig to add Instant Client to the system wide library search path.

    Configuring ldconfig is an effective and commonly used solution. However it has a potential problem that if multiple Oracle products exist, with possibly differing versions of Oracle libraries on the same machine, then there might be library clashes. If you wish to use it, create a file /etc/ld.conf.so.d/oracle-instant-client.conf containing:

    /opt/oracle/instantclient_12_1
    

    Then update the linker cache by running:

    ldconfig

    Alternatively set LD_LIBRARY_PATH in Apache's environment file, /etc/sysconfig/httpd. In Oracle Linux 6 use:

    export LD_LIBRARY_PATH=/opt/oracle/instantclient_12_1
    

    In Oracle Linux 7 use:

    LD_LIBRARY_PATH=/opt/oracle/instantclient_12_1
    

    In Oracle Linux 7, don't reference variables on the right-hand side of the equals sign since they won't be expanded.

    [The Apache environment configuration file location varies between Linux distributions. On OpenSUSE see /etc/sysconfig/apache2. On Debian-based distributions look at /etc/apache2/envvars].

  6. Set any other Oracle environment variables in the Apache environment configuration file /etc/sysconfig/httpd. For example:

    NLS_LANG=GERMAN_GERMANY.AL32UTF8
    

    (Prefix any variable setting with export in Oracle Linux 6)

  7. Install mod_wsgi:

    yum install mod_wsgi
    
  8. Add this line to /etc/httpd/conf/httpd.conf:

    WSGIScriptAlias /wsgi_test /var/www/html/wsgi_test.py
    
  9. On Oracle Linux 6, start the web server with:

    service httpd start
    

    On Oracle Linux 7 use:

    systemctl start httpd.service
    
  10. Create a test file /var/www/html/wsgi_test.py that connects to your database:

    #-*- coding: utf-8 -*-
    
    def query():
        import cx_Oracle
        db = cx_Oracle.connect("hr", "welcome", "localhost/orcl")
        cursor = db.cursor()
        cursor.execute("select city from locations where location_id = 2200")
        return cursor.fetchone()[0]
    
    def wsgi_test(environ, start_response):
        output = query()
    
        status = '200 OK'
        headers = [('Content-type', 'text/plain'),
    	       ('Content-Length', str(len(output)))]
        start_response(status, headers)
        yield output
    
    application = wsgi_test
    
  11. Load http://localhost/wsgi_test in a browser. The city of the queried location id will be displayed.

That's it. Let me know how it works for you.

Information on cx_Oracle can be found here.

Information on Oracle Linux can be found here.

Information on Oracle Database can be found here.

Thursday Apr 24, 2014

Installing PHP on Oracle HTTP Server 12c

OTN have posted an updated guide for installing PHP on Oracle HTTP Server. Check it out!

Using PHP-FPM is a great way to integrate with Oracle Fusion Middleware.

Wednesday Mar 23, 2011

Building PHP 5.3 with Oracle HTTP Server 11g

[Read More]

Wednesday Nov 04, 2009

Zend Server and Oracle Enterprise Linux

[Read More]
About

Tourists looking out over an Opal mine
I'm a Product Manager in Server Technologies, working on scripting languages and developer-access.
Email: christopher.jones@oracle.com
Twitter: http://twitter.com/ghrd
Links: OTN Node.js Developer Center
OTN PHP Developer Center
Book: Free PHP Oracle book

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