Installing and Connecting

Getting started with Oracle Database involves choosing an installation method, creating a database, and connecting with client tools. This lesson covers the most common approaches for developers and administrators.

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Installation Options

Option	Best For	Notes
Oracle Database XE	Development and learning	Free, limited to 2 CPUs, 2 GB RAM, 12 GB user data
Oracle Database EE/SE2	Production workloads	Requires a licence
Oracle Cloud (Autonomous DB)	Cloud-native development	Always Free Tier available
Docker / Podman	Quick local environments	Official Oracle container images on GitHub
Oracle VirtualBox Appliance	Pre-built environments	Complete VM with database pre-installed

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Installing Oracle Database XE on Linux

Prerequisites

• Oracle Linux 8/9, Red Hat 8/9, or compatible
• At least 2 GB RAM and 10 GB disk space

Steps

# 1. Install the Oracle XE RPM
sudo dnf install oracle-database-xe-21c-1.0-1.ol8.x86_64.rpm

# 2. Run the configuration script
sudo /etc/init.d/oracle-xe-21c configure

# 3. You will be prompted to set the SYS and SYSTEM passwords

# 4. Set environment variables
source /opt/oracle/product/21c/dbhomeXE/bin/oraenv

After installation, the database starts automatically with a Container Database (CDB) named XE and a Pluggable Database (PDB) named XEPDB1.

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Installing with Docker

Oracle provides official container images:

# Pull the Oracle XE image
docker pull container-registry.oracle.com/database/express:latest

# Run the container
docker run -d \
  --name oracle-xe \
  -p 1521:1521 \
  -p 5500:5500 \
  -e ORACLE_PWD=YourPassword123 \
  container-registry.oracle.com/database/express:latest

# Check logs (database creation takes a few minutes)
docker logs -f oracle-xe

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Oracle Cloud Autonomous Database

For a zero-installation experience:

1. Sign up at cloud.oracle.com (Always Free Tier)
2. Navigate to Autonomous Database → Create
3. Choose a workload type (Transaction Processing or Data Warehouse)
4. Download the Wallet file for secure connections
5. Connect using SQL Developer, SQLcl, or any JDBC/ODBC client

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Environment Variables

Set these in your shell profile (~/.bashrc or ~/.bash_profile):

export ORACLE_HOME=/opt/oracle/product/21c/dbhomeXE
export ORACLE_SID=XE
export PATH=$ORACLE_HOME/bin:$PATH
export LD_LIBRARY_PATH=$ORACLE_HOME/lib

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Connecting with SQL*Plus

SQL*Plus is the classic command-line tool included with every Oracle installation:

# Connect as SYSDBA (administrative)
sqlplus / as sysdba

# Connect to a PDB as a regular user
sqlplus hr/password@localhost:1521/XEPDB1

# Connect using Easy Connect syntax
sqlplus hr/password@//hostname:port/service_name

Common SQL*Plus Commands