Making the most of Oracle 18c XE – Pluggable Databases and the Oracle Eco-System

This was going to be a simple post about creating multiple Pluggable Databases (PDBs) in Oracle 18cXE.
But you know what it’s like, you get your lego database set out and then you spot those unusual shaped bricks… and the transparent ones… oh, that one has a wheel on…and get a bit carried away.
What follows is a guide on how to create three concurrent PDBs on an Oracle 18cXE database. However, I have taken the opportunity to investigate other areas of the Express Edition platform and so will be making use of Advanced Compression as well as Oracle Enterprise Manager Express.
In fact, I wouldn’t be surprised if SQLDeveloper put in an appearance as well.
I’ve also included a couple of the more notable members of Oracle’s small-but-perfectly-formed eco-system into the final design. On top of all that, I’ll be performing a magic trick to ensure that I only have to install each piece of software once, even though it may end up in multiple PDBs…
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Installing and Configuring Oracle 18cXE on CentOS

After seven years, the much anticipated Oracle 18c Express Edition (XE) has finally seen the light of day.
Reaction to the new version can be summed up as…

It’s the Dog’s Wotsits !

Gerald Venzl, the person we have to thank for this new and vastly improved version of XE, has already published an installation guide.

At this point you may well ask yourself that what – apart from gratuitous puppy pics and cheesy-snack-based puns – is the difference between that post and this.

Well, if you’re a long-time user of 11gXE and you’re looking to upgrade then you will find 18cXE a rather different proposition.
The introduction of Multitenant databases aside, 18cXE differs greatly from it’s predecessor in terms of it’s functional scope.
Wheras 11gXE was – broadly speaking – functionally equivalent to Oracle Standard Edition, the approach for 18cXE has been to shoe-horn in as many Enterprise Edition features as possible.
No doubt, this will leave you anxious to play with the new version. However, there are some “home comforts” that were present in the old version that you’ll need to configure yourself this time around.
What I’m going to go through is :

  • Installing 18cXE on a Red Hat compatible distro (CentOS7)
  • Connecting to the database and exploring the containers
  • Checking the TNS Listener
  • Manual and Automatic Startup and Shutdown of the database and listener
  • Setting and persisting the Oracle environment variables
  • Accessing Enterprise Manager Express
  • Installing the HR demo application in a Pluggable Database (PDB)
  • Configuring the firewall to allow remote access to Oracle

The steps documented here have been performed on a vanilla installation of CentOS7. As such, they should work pretty much unaltered for other Red Hat based distros based on or similar to Red Hat Enterprise Linux (RHEL) version 7.

Before all of that though… Continue reading