Oracle Database 12c Installation on CentOS 7

Oracle Database 12c is a popular relational database management system used by enterprises worldwide. Installing Oracle Database 12c on CentOS 7 involves several steps, including prerequisite checks, downloading the necessary files, and running the installer. This article provides a detailed guide to help you complete the installation successfully.
Before you proceed, ensure that your system meets the following prerequisites:

• Oracle Database 12c requires a minimum of 512MB of RAM, but it is recommended to allocate at least 1GB of RAM for optimal performance.
• The operating system must be CentOS 7 with a 64-bit architecture.
• Install the necessary prerequisites, including Java Development Kit (JDK) and Microsoft Visual C++ Redistributable.
• Download the Oracle Database 12c software from Oracle’s website and save it on your system.
  Once you have met the prerequisites and downloaded the software, follow these steps to install Oracle Database 12c on CentOS 7:

1. Open a terminal window and navigate to the directory where you saved the Oracle Database installation files.
2. Run the following command to set the necessary environment variables:
   export ORACLE_BASE=/u01/app/oracle
   export ORACLE_HOME=$ORACLE_BASE/product/12.2.0/dbhome_1
   export ORACLE_SID=orcl
3. Create the Oracle database directory by running the following command:
   sudo mkdir -p $ORACLE_BASE
4. Create a new group for Oracle users by running the following command:
   sudo groupadd oinstall
5. Add the Oracle user to the new group by running the following command:
   sudo useradd -g oinstall -d /dev/null oracle
6. Set the appropriate permissions for the Oracle user and group on the Oracle base directory by running the following command:
   sudo chown -R oracle:oinstall $ORACLE_BASE
7. Set the password for the Oracle user account by running the following command:
   sudo passwd oracle
8. Run the Oracle Database installation program by executing the following command:
   ./runInstaller
9. Follow the on-screen instructions to complete the installation process. You will be prompted to select a language, enter the necessary information, and accept the license agreement.
10. Select the appropriate options during the installation process, such as creating a new database, selecting a character set, and configuring networking settings.
11. Once the installation is complete, you will be prompted to set up Automatic Diagnostic Repository (ADR) if you want to enable automatic problem diagnosis and resolution.
12. Finally, start the database using the following command:
    source $ORACLE_HOME/sqlplus/admin/sqlplusrc.ora
    sqlplus / as sysdba
    whatis dbstart
13. You can now access the Oracle Database Management Console (DBMC) using your web browser and navigate to http://localhost:5500/em.
    Post-installation configurations may include setting up listeners, configuring network protocols, and creating users and schemas.
    Remember to back up your database regularly and update your system and software components to ensure security and compatibility with future releases.
    By following these steps, you should be able to successfully install Oracle Database 12c on CentOS 7. If you encounter any issues during the installation process, refer to Oracle’s official documentation or seek help from Oracle support forums.
    Remember to handle sensitive information such as passwords and encryption keys with caution to maintain data security.