I have a 64-bit Windows 7 machine with an Oracle 11g version installed. I want to install the Oracle 18c version on the same machine.

Is it possible? If yes, what are the configurations I need to do for them (11g and 18c) to coexist?


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    Do you like to install the database or just the client? Mar 13 '19 at 9:06
  • You didn't specify which edition. You can only have 1 instance of Express Edition (XE) at a time on the server irregardless of versions. Mar 13 '19 at 10:49
  • The database @WernfriedDomscheit. Mar 15 '19 at 1:28
  • Hi @MichaelKutz, yes I'm using XE for 11g and 18c. Is there no possible workaround? We only have one machine for our databases. Thanks Mar 15 '19 at 1:29
  • Btw @MichaelKutz. what will happen if I both 11g and 18c XE are installed in the same machine? Mar 15 '19 at 1:36

Can you run 11g and 18c on the same machine for SE2/EE editions?


I'd place them in different ORACLE_HOMEs. BUT, you only need to run 1 Listener.

Can you run 11g and 18c on the same OS if both are XE?

no. (But - 18c XE can run in a VM)

11g XE License limits you to one XE instance per physical machine.

Any use of the Oracle Database Express Edition is subject to the following limitations;

  1. Express Edition is limited to a single instance on any server;
  2. Express Edition may be installed on a multiple CPU server, but may only be executed on one processor in any server;
  3. Express Edition may only be used to support up to 11GB of user data (not including Express Edition system data);
  4. Express Edition may use up to 1 GB RAM of available memory.

18c XE License does not have Condition 1 from 11g XE. As I understand, this was done so that you can run 18c XE inside a VM:

Oracle Database 18c Express Edition automatically constrains itself to the following resource restrictions;

  1. 2 CPU threads;
  2. 2 GB of RAM; and
  3. 12 GB of user data.

The code also prevents you from running multiple XE instances on the same host. ( source )

4.2 Oracle Database XE Installation and Execution Restrictions

Oracle Database XE restricts itself to only one installation per logical environment. The logical environment can either be a virtual host such as a VM or container, or a physical host. If more than one Oracle Database XE installation is attempted to be started in such a logical environment, an "ORA-00442: Oracle Database Express Edition (XE) single instance violation error" is raised and the database will not start.

But, certain VM technologies are supported. That is: You can run multiple instance of XE as long as each one is in a different Virtual Host.

Oracle certifies the following virtualization technologies with Oracle Database on Windows:

  • Oracle VM Server
  • Microsoft Hyper-V

First thing to do: Backup your machine and data. Then, run your 18c install (good news - it is supported - but for how long, see below). Verify if there are problems.

  • Test.
  • Test again.
  • Oh, did I mention, test?

You haven't mentioned your version of 7, or your hardware, however, I have a few questions:

From here:

When does support for Windows 7 end? Microsoft ended mainstream support for Windows 7 on January 13, 2015, but extended support won’t end until January 14, 2020. Find out the difference between mainstream and extended support.

So, why are you using an unsupported Operating System (well, not fully supported, see here)?

IMHO, if you wish to persist with Windows, I would upgrade to Windows 10. There was no Windows 9, so Windows 10 is essentially an odd-numbered OS. Generally, the odd-numbered versions of Windows are relatively good, but the even-numbered ones are dire (anyone remember Vista (shudder)?). 10 is decent enough (graphic interface is very slick) - not really important for db work, but hey, if you're running a no-choice GUI, why not have a nice one?

The second question is why don't you take the leap and go to Linux? If you wish to compartmentalise your different releases, you can separate them relatively easily on that OS.

If this is a dev machine, 5 years ago, I would have recommended using VMs but now there's only really one choice - containers! See this article from the superb site oracle-base from Tim Hall (check out his other articles for anything Oracle related - particularly Linux installs). A word of warning: I have no clue about running Oracle containers on Windows, but after having Googled:

You could also go to the cloud for your 18c work? If this is for dev, you could do your initial work on 11g but then "polish it off" on 18c on the cloud for, perhaps (YMMV), not too much $$?

Overall, you have lots of options, but my recommendations are to:

  • get rid of Windows 7 (-> 10 or a server edition)

  • run containers for 18c on a server edition, and 11g (on a VM)?

  • better (maybe), use containerisation and/or cloud to run your 18c db.

  • best better still go to Linux

  • Hi @Vérace, unfortunately the current machine we're working on is provided by company. And applying changes (per your suggestions) requires a lot of time and money which I don't have the luxury. Thanks anyway. Mar 15 '19 at 1:31
  • Fair enough - that happens a lot that dbas/programmers/people aren't allowed change their environments. However, if (and only if) you found my answer helpful, you could mark it with an upvote? Mar 15 '19 at 1:47

I think in principle it should be possible but it will be very difficult. There are some components which can be installed only once per machine (or one each for 32-bit and 64-bit), e.g. "Oracle Administration Assistant for Windows" or "Oracle Provider for OLE DB".

The behavior of the Oracle installer changed over the releases. If you find some Oracle documentation "Installing Oracle Database into Multiple Oracle Homes" they might be valid for version 11.1 + 11.2 but not 11c + 18g.

You will have to check/modify environment variables like PATH, ORACLE_HOME, etc. every time before you start an application or process, this can be rather painful.

Better go for dedicated virtual Windows (or Linux) environment for each Oracle installation.

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