Oracle Database/Introduction

Oracle RDBMS is one of the most used relational database management system^[1]. It has been created in 1979 and its request language is called the PL/SQL.

Installing Oracle

As with most software products, it must be installed; Windows, Linux and Unix versions are available for use, and there are different editions available.

• Express Edition (XE)^download is free but uses a slightly older version of the Oracle database engine, and has upper RAM and storage limits of 4 GB in mono-processor. It is not available for Unix and needs to register online.
• Standard Edition One removes the basic limitations for storage, and will support multi-cpu systems.
• Standard Edition (SE) provides additional features pertaining to cluster management (Oracle Real Application Clusters, alias Oracle RAC), and may be run on systems containing additional CPUs.
• Enterprise Edition (EE) has no limitations, and may also include optional features that are suitable to large corporations.
• Personal Edition (PE) is not provided for the 12th version. It was a kind of single user Enterprise Edition.

Once downloaded, the .zip file(s) must be extracted, if they are two their folders must be merged (they are named "database"). Then launch to install:

• In Linux, runInstaller.sh.
• In Windows, setup.exe.

Starting script

Oracle Database launches automatically at each boot, which is useful for a server but slows the system significantly for a PC which isn't supposed to use it in full time. To avoid this we can create a simple script to launch and stop Oracle manually:

• In Linux : remove Oracle from the daemons (eg: /etc/init.d).
• In Windows : execute services.msc, and toggle the services OracleServiceXE and OracleXETNSListener in manual start. When you need to use Oracle, launch as an administrator, the following script Oracle.cmd:
  • For the XE version:

     net start OracleServiceXE
     net start OracleXETNSListener
     pause
     net stop OracleXETNSListener
     net stop OracleServiceXE
    

  • For the SE version:

     net start OracleServiceORCL
     net start OracleDB12Home1TNSListener
     pause
     net stop OracleDB12Home1TNSListener
     net stop OracleServiceORCL
    

If the message "Access denied" occurs, relaunch the script with a right click, as an administrator.

Identifying system requirements

The database server needs at least^[2]:

1. 1 GB free space on a hard drive for XE, 3.5 for SE.
2. 1 GB RAM.
3. Windows, Linux, Oracle Solaris, or IBM AIX.

Since the version 12c, a 64 bits processor is mandatory.

The environment variables settings are automatic.

The system objects naming follows the Optimal Flexible Architecture (OFA). ^[3]

References