Add notes about the author

- to ensure even an absolute beginner gets a PostgreSQL server up
  and running, the default installation assumes that the student
  first installs VirtualBox with a Ubuntu Desktop machine in it
- on the Ubuntu guest machine, the apt packages postgresql and
  postgresql-contrib are installed first

INSTALL.md

@@ -0,0 +1,474 @@
+# Installation Tutorial
+
+To follow this course, an installation of **PostgreSQL 13** or higher is expected.
+
+The following is a detailed tutorial as to
+    how to install and set up a Postgres server
+    on an [Ubuntu Linux](https://ubuntu.com) machine
+    that is run **[virtually <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Virtual_machine)**
+    on the student's own laptop or workstation by [VirtualBox](https://www.virtualbox.org/).
+VirtualBox is freely available for all major operating systems
+    (i.e., MacOS, Linux, and Windows).
+It is used in this course as then each student should be able
+    to follow the further installation instructions below easily
+    and end up having a development environment similar to the instructor's one.
+Of course, students may also use any other way of setting up a PostgreSQL server;
+    most notably, they may install it on their machine *without* a virtualization.
+
+
+## Install VirtualBox
+
+Go to [virtualbox.org](https://www.virtualbox.org/),
+    download the latest version of VirtualBox for your operating system,
+    and install it according to the instructions given there.
+
+
+## Create a new Virtual Machine
+
+First, go to [ubuntu.com](https://ubuntu.com/download/desktop),
+    download the latest version (i.e., 21.04 at the time of this writing)
+        of **Ubuntu Desktop** (i.e., *not* server),
+    and proceed with the following steps.
+Ubuntu is available for free;
+    the name of the downloaded file should be something like "*ubuntu-21.04-desktop-amd64.iso*"
+    (i.e., one big ISO file).
+This file represents the contents of an "Ubuntu Installation DVD".
+
+<img src="static/installation/0_create_vm_0_download_ubuntu.png" width="80%" align="center">
+
+Next, create a new virtual machine in VirtualBox
+    by clicking on the blue "New" button in the toolbar on the top.
+Note that the screenshots of VirtualBox's overview window below
+    already show an older virtual machine running Windows 10.
+
+<img src="static/installation/0_create_vm_1_overview_without_new_machine.png" width="80%" align="center">
+
+A helper widget opens.
+Specify the following settings:
+1. Name the virtual machine (e.g. "*Ubuntu_21.04*")
+   and choose a folder on your personal computer
+       where the virtual machine's data are stored
+       (e.g. "*/home/webartifex/vboxes*").
+   The type and version should already be set automatically.
+2. Choose the amount of memory (i.e., RAM)
+   that the virtual machine is allowed to use:
+   This should be around 33% to 66% of your personal computer's capacity
+   (if unsure, take the recommended default).
+3. Create a *new* virtual hard disk,
+4. keep the hard disk file type as "*VDI*",
+5. have the storage on the physical hard disk allocated *dynamically*, and
+6. choose a big enough maximum size for the file holding the virtual hard disk
+   (10-25 GB is sufficient to follow this course).
+   Dynamic disk space allocation means that
+       not all of this space is used right away on your personal computer.
+
+<img src="static/installation/0_create_vm_2_name.png" width="60%" align="center">
+
+<img src="static/installation/0_create_vm_3_memory.png" width="60%" align="center">
+
+<img src="static/installation/0_create_vm_4_hard_disk.png" width="60%" align="center">
+
+<img src="static/installation/0_create_vm_5_hard_disk_type.png" width="60%" align="center">
+
+<img src="static/installation/0_create_vm_6_dynamic_allocation.png" width="60%" align="center">
+
+<img src="static/installation/0_create_vm_7_hard_disk_size.png" width="60%" align="center">
+
+After this, the new virtual machine should show up in the overview.
+
+<img src="static/installation/0_create_vm_8_overview_with_new_machine.png" width="80%" align="center">
+
+To start the new virtual machine,
+    click on the green "Start" arrow in the toolbar
+    while the machine is selected on the left.
+A second VirtualBox window opens showing the virtual machine's screen.
+On the first start-up, a widget should come up automatically
+    (see next paragraph if the widget does not appear)
+    asking to select a start-up disk (i.e., a CD or DVD)
+    from which the empty virtual machine should boot up.
+Choose the downloaded ISO file from above
+    (if it is not already found automatically)
+    and proceed by clicking on "Start".
+Continue with the "[Install Ubuntu](#install-ubuntu)" step below.
+
+<img src="static/installation/1_first_boot_0_select_startup_disk.png" width="60%" align="center">
+
+
+### Inserting CDs/DVDs
+
+If the "Select start-up disk" widget does *not* show up automatically,
+    the virtual machine will *not* boot at all.
+After all, its hard drive is empty and no DVD/ISO is "laid in".
+So, its screen remains black.
+In that case, close the window with the running virtual machine:
+    In the prompt, choose the "Power off the machine" option.
+Then, in the overview,
+    click on the orange "Settings" button in the toolbar
+    while the machine is selected on the left.
+A "Settings" widget opens: Choose the "Storage" tab on the left.
+There, click on the round disk symbol to the right of "Controller: IDE",
+    which opens another "Optical Disk Selector" widget.
+In that, click on the "Add" button,
+    choose the downloaded ISO file from above, and
+    click on "Choose" to confirm the selection.
+Now, you should see the ISO file's name
+    below the "Controller: IDE" option in the middle.
+Finally, close the "Settings" menu by clicking "Ok"
+    and start the virtual machine again.
+
+<img src="static/installation/1_first_boot_1_overview_with_new_machine.png" width="80%" align="center">
+
+<img src="static/installation/1_first_boot_2_settings.png" width="60%" align="center">
+
+<img src="static/installation/1_first_boot_3_choose_iso.png" width="60%" align="center">
+
+<img src="static/installation/1_first_boot_4_confirm.png" width="60%" align="center">
+
+
+## Install Ubuntu
+
+With the Ubuntu Installation DVD/ISO "laid in",
+    the virtual machine should now boot up properly
+    and stop at a "Welcome" screen.
+There, click on the "Install Ubuntu" button.
+You may want to choose a language other than "English".
+
+**Note**: Once you click somewhere with your mouse inside a virtual machine,
+    the mouse pointer is said to be "captured" by that machine and
+    you can *not* leave the virtual machine any more with your mouse.
+Then, you must press the so-called **host key** first.
+By default, this is the right "*Ctrl*" key on your keyboard.
+
+<img src="static/installation/2_install_ubuntu_0_welcome.png" width="80%" align="center">
+
+Sometimes, the boot process "hangs" at a black "boot loader" screen.
+If so, simply choose the "Ubuntu" option
+    with your keyboard's arrow and "Enter" keys.
+That should take you to the above "Welcome" screen.
+
+<img src="static/installation/2_install_ubuntu_1_boot_loader.png" width="80%" align="center">
+
+From the "Welcome" screen, follow the installation guide:
+1. Choose a keyboard layout corresponding to your *physical* computer,
+2. select "Minimal Installation" including the "other options",
+3. erase the virtual hard disk,
+4. specify where you are located,
+5. create a user account to sign on,
+6. wait for the installation to finish, and
+7. remove the Installation DVD/ISO
+   (by right-clicking on the gray disk symbol below the screen
+    and choosing "Remove ...";
+    it may be that this happens automatically).
+
+<img src="static/installation/2_install_ubuntu_2_keyboard_layout.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_3_packages.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_4_clean_install_0.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_4_clean_install_1.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_5_location.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_6_user.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_7_finish_0.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_7_finish_1.png" width="80%" align="center">
+
+<img src="static/installation/2_install_ubuntu_8_restart.png" width="80%" align="center">
+
+
+### Configure Ubuntu
+
+After installation, the virtual machine may reboot automatically.
+If not, simple start it again.
+This takes you to the login screen.
+Sign on with the credentials you specified during installation.
+
+<img src="static/installation/3_configure_ubuntu_0_first_startup.png" width="80%" align="center">
+
+If an "Update" widget appears in the next moments,
+    simply ignore it by clicking "Remind me later".
+You will learn how to update an Ubuntu system from the command line further below.
+
+<img src="static/installation/3_configure_ubuntu_1_update.png" width="60%" align="center">
+
+After the first sign-on, a "First Steps" wizard pops up.
+As Ubuntu is only installed on a virtual machine,
+    do not connect to any online accounts,
+    turn off the background telemetry (e.g., crash reports), and
+    disable the location services.
+
+<img src="static/installation/3_configure_ubuntu_2_wizard_0_online_accounts.png" width="80%" align="center">
+
+<img src="static/installation/3_configure_ubuntu_2_wizard_1_telemetry.png" width="80%" align="center">
+
+<img src="static/installation/3_configure_ubuntu_2_wizard_2_location_share.png" width="80%" align="center">
+
+<img src="static/installation/3_configure_ubuntu_2_wizard_3_apps.png" width="80%" align="center">
+
+Next, open the application launcher
+    by clicking on the dots in the lower left corner,
+    seach for the "Terminal" app,
+    and open it.
+
+<img src="static/installation/3_configure_ubuntu_3_terminal_0.png" width="80%" align="center">
+
+<img src="static/installation/3_configure_ubuntu_3_terminal_1.png" width="80%" align="center">
+
+
+### Update Ubuntu
+
+The first thing you want to always do after a fresh installation
+    is to check for available updates.
+The command to enter in the terminal is `sudo apt update`.
+`sudo` is simply the Linux way of saying
+    "the following command needs administrator privileges".
+`apt` is Ubuntu's default program to manage the installed [software packages <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Package_manager).
+The sub-command `update` checks if updates are available.
+Using `sudo` implies that you have to enter your user's password in the terminal.
+
+<img src="static/installation/4_update_ubuntu_0_apt_update_0.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_0_apt_update_1.png" width="80%" align="center">
+
+As we can tell from the previous screenshot,
+    there are packages that can be upgraded.
+To start the upgrade process, type `sudo apt upgrade`.
+The terminal then asks if it should proceed
+    while listing all the packages to be upgraded.
+Press the "Enter" key to continue.
+
+<img src="static/installation/4_update_ubuntu_1_apt_upgrade_0.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_1_apt_upgrade_1.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_1_apt_upgrade_2.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_1_apt_upgrade_3.png" width="80%" align="center">
+
+Commonly, when individual packages are upgraded,
+    they may not need some other package any more to work.
+In general, we say that if package *A* needs package *B* to function correctly,
+    package *B* is a [dependency <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Coupling_%28computer_programming%29) of package *A*.
+The command `sudo apt autoremove` removes unneeded packages
+    from the virtual machine, freeing some of its hard drive's storage.
+
+<img src="static/installation/4_update_ubuntu_2_apt_autoremove_0.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_2_apt_autoremove_1.png" width="80%" align="center">
+
+<img src="static/installation/4_update_ubuntu_2_apt_autoremove_2.png" width="80%" align="center">
+
+Finally, after the system upgrade, restart the machine.
+You can do that
+    by clicking on the tray icons in the upper right corner
+    and using the provided graphical options.
+
+<img src="static/installation/4_update_ubuntu_3_restart.png" width="80%" align="center">
+
+Congratulations!
+You now have a virtual machine running the latest Ubuntu Linux.
+
+
+## Install VirtualBox's Guest Additions
+
+In order to make the newly created *virtual* Ubuntu machine,
+    which takes the role of the **guest** system,
+    interact seamlessly with your *physical* computer,
+    which takes the role of the **host** system,
+    you can (and should) install VirtualBox's [Guest Additions](https://www.virtualbox.org/manual/ch04.html).
+One example for a seamless integration is
+    that the guest system's screen resolution auto-adjusts
+    whenever you resize the VirtualBox window in that it is running.
+
+To install the Guest Additions,
+    first start the virtual machine and sign in.
+Then, choose the "Insert Guest Additions CD image ..." in the "Devices" menu
+    in the enclosing VirtualBox window.
+Just to state the maybe obvious:
+    This menu option is *not* available in the Ubuntu system.
+Depending on your host system, the menu may look different.
+If this option does not exist at all,
+    you could also "insert" the Guest Additions CD
+    as described in the "[Inserting CDs/DVDs](#inserting-cdsdvds)" section above.
+You may be prompted to download the Guest Additions ISO file first.
+
+<img src="static/installation/5_guest_additions_0_insert_disk_0.png" width="80%" align="center">
+
+<img src="static/installation/5_guest_additions_0_insert_disk_1.png" width="40%" align="center">
+
+<img src="static/installation/5_guest_additions_0_insert_disk_2.png" width="40%" align="center">
+
+The Ubuntu guest system should automatically detect
+    that the inserted CD has an auto-run option.
+Simply, click "Run" and confirm the action with your user's password.
+
+<img src="static/installation/5_guest_additions_1_autostart.png" width="80%" align="center">
+
+A script is run inside a terminal window.
+Wait until this is finished and hit the "Enter" key.
+
+<img src="static/installation/5_guest_additions_2_install.png" width="80%" align="center">
+
+After the installation of the Guest Additions,
+    do not forget to eject the CD
+    by right-clicking on the disk symbol and selecting "Eject".
+
+<img src="static/installation/5_guest_additions_3_eject.png" width="80%" align="center">
+
+
+### Add a Shared Folder
+
+Another benefit of installing the Guest Additions is
+    that you can set up a shared folder
+    between your physical host system and the virtual Ubuntu guest system.
+You can use that, for example,
+    to back up SQL files created inside the virtual machine
+    in your common file system.
+
+First, power off the machine
+    and open the "Settings" widget with the orange "Settings" button in the toolbar.
+There, go to the "Shared Folders" tab on the left.
+Then, click on the "Add Folder" symbol on the right,
+    and choose a folder on your personal computer's file system
+    (e.g., a good choice could be your "Desktop" folder).
+Also, check the "Auto-mount" option.
+
+<img src="static/installation/6_shared_folder_0.png" width="60%" align="center">
+
+<img src="static/installation/6_shared_folder_1.png" width="40%" align="center">
+
+<img src="static/installation/6_shared_folder_2.png" width="60%" align="center">
+
+After signing in the next time,
+    Ubuntu's file browser should show you the shared folder
+    (i.e., "*sf_shared*" in the screenshot below)
+    as an external drive (i.e., that's why the "Eject" symbol is next to "*sf_shared*").
+
+<img src="static/installation/6_shared_folder_3.png" width="80%" align="center">
+
+
+## Install PostgreSQL Server
+
+With a ready Ubuntu installation it is now time
+    to install and set up a [PostgreSQL](https://www.postgresql.org/) server.
+
+To do so, open a new terminal window in the virtual machine
+    and run the `sudo apt install postgresql postgresql-contrib` command.
+The `install` sub-command of the `apt` program does what we expect it to.
+While the `postgresql` package contains all the basic features,
+    the `postgresql-contrib` package offers some common [additional modules](https://www.postgresql.org/docs/10/contrib.html).
+
+<img src="static/installation/7_install_postgres_0.png" width="80%" align="center">
+
+<img src="static/installation/7_install_postgres_1.png" width="80%" align="center">
+
+<img src="static/installation/7_install_postgres_2.png" width="80%" align="center">
+
+<img src="static/installation/7_install_postgres_3.png" width="80%" align="center">
+
+With the command `sudo service postgresql status` one can check
+    if Postgres is running as a service on the virtual machine.
+To exit the status view, press the "q" key.
+
+<img src="static/installation/7_install_postgres_4.png" width="80%" align="center">
+
+
+## Install Git
+
+To clone the [GitHub repository <img height="12" style="display: inline-block" src="static/link/to_gh.png">](https://github.com/webartifex/intro-to-sql)
+        with the materials for this course,
+    you must first install the [git](https://git-scm.com/) utility.
+`git` is a so-called **[version control <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Version_control)** software.
+
+To do so, run the command `sudo apt install git` in a terminal.
+
+<img src="static/installation/8_install_git_0.png" width="80%" align="center">
+
+<img src="static/installation/8_install_git_1.png" width="80%" align="center">
+
+<img src="static/installation/8_install_git_2.png" width="80%" align="center">
+
+To check if `git` works,
+    you could run a command like `git --version`
+    that simply shows the installed version of `git`.
+
+<img src="static/installation/8_install_git_3.png" width="80%" align="center">
+
+`git` is a tool worth learning about in detail.
+As a reading recommendation,
+    the best source for an introduction to `git`
+    is probably the official [online book](https://git-scm.com/book/en/v2/).
+
+
+### Configure Git
+
+To get `git` to work in our virtual machine,
+    we must at least go through the [First-time Git Setup](https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup) chapter
+    in the official book.
+In summary,
+    you simply have to specify your name and email (or anonymous substitutes)
+    in a terminal with the following commands:
+- `git config --global user.name "<your name>"` and
+- `git config --global user.email "<your email>"`.
+
+To check if the configuration is stored, run `git config --list`.
+
+<img src="static/installation/9_configure_git.png" width="80%" align="center">
+
+
+### Download the Course Materials
+
+To obtain your own copy of the course materials,
+    you must "[clone](https://git-scm.com/book/en/v2/Git-Basics-Getting-a-Git-Repository)"
+    the [GitHub repository <img height="12" style="display: inline-block" src="static/link/to_gh.png">](https://github.com/webartifex/intro-to-sql)
+        with the materials.
+That is done with the command `git clone https://github.com/webartifex/intro-to-sql.git`.
+In the screenshot,
+    you see this done
+    after going into the virtual machine's "Desktop" folder with `cd Desktop/`.
+Alternatively, you could clone the repository into your user's home folder
+    (i.e., what the `~` means).
+
+<img src="static/installation/10_download_materials.png" width="80%" align="center">
+
+
+## Verify Python works
+
+As this course also shows
+    how to embed a database like Postgres
+    in a typical backend application,
+    written, for example, in [Python <img height="12" style="display: inline-block" src="static/link/to_py.png">](https://www.python.org/),
+    we need to ensure that we can start a Python process.
+
+By default, recent Ubuntu versions
+    come with [Python 3 <img height="12" style="display: inline-block" src="static/link/to_py.png">](https://docs.python.org/3/) pre-installed.
+The command `sudo apt install python3` confirms that:
+    The `python3` package is already there.
+
+<img src="static/installation/11_install_python_0.png" width="80%" align="center">
+
+<img src="static/installation/11_install_python_1.png" width="80%" align="center">
+
+We could just as well start an interactive Python shell
+    with the simple `python3` command.
+
+<img src="static/installation/11_install_python_2.png" width="80%" align="center">
+
+Typing `python` for short instead fails.
+This command used to point to the Python 2 installation, which has been discontinued.
+
+<img src="static/installation/11_install_python_3.png" width="80%" align="center">
+
+For convenience, install the `python-is-python3` package.
+Then, you may use the `python` and `python3` commands interchangeably.
+
+<img src="static/installation/11_install_python_4.png" width="80%" align="center">
+
+<img src="static/installation/11_install_python_5.png" width="80%" align="center">
+
+Congratulations!
+You are now all set to follow this course and learn about SQL.
+

README.md

@@ -3,5 +3,42 @@
 This project is a *thorough* introductory course
     in **[SQL <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/SQL)**
     and **[databases <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Database)**
-    based on the free and open-source database [PostgreSQL <img height="12" style="display: inline-block" src="static/link/to_postgres.png">](https://www.postgresql.org/).
+    based on the free and open-source database **[PostgreSQL <img height="12" style="display: inline-block" src="static/link/to_postgres.png">](https://www.postgresql.org/)** (or "Postgres" for short).
+
+
+## Installation
+
+To follow this course, an installation of **PostgreSQL 13** or higher is expected.
+If you know how to do this on your own machine,
+    you may do so at your own discretion.
+Yet, to ensure that
+    each student has a development environment
+    similar to the instructor's one,
+    follow this *extensive* **[installation tutorial](INSTALL.md)**
+    and set up a [virtual machine <img height="12" style="display: inline-block" src="static/link/to_wiki.png">](https://en.wikipedia.org/wiki/Virtual_machine)
+    with all the required software on it.
+The estimated time for this should be around *one hour*.
+
+
+## Contributing
+
+Feedback **is highly encouraged** and will be incorporated.
+Open an issue in the [issues tracker <img height="12" style="display: inline-block" src="static/link/to_gh.png">](https://github.com/webartifex/intro-to-sql/issues)
+    or initiate a [pull request <img height="12" style="display: inline-block" src="static/link/to_gh.png">](https://help.github.com/en/articles/about-pull-requests)
+    if you are familiar with the concept.
+Simple issues that *anyone* can **help fix** are, for example,
+    **spelling mistakes** or **broken links**.
+If you feel that some topic is missing entirely, you may also mention that.
+The materials here are considered a **permanent work-in-progress**.
+
+
+## About the Author
+
+Alexander Hess is a PhD student
+    at the Chair of Logistics Management at [WHU - Otto Beisheim School of Management](https://www.whu.edu)
+    where he conducts research on urban delivery platforms
+    and teaches coding and data science courses
+    based on Python & SQL in the BSc and MBA programs.
+
+Connect with him on [LinkedIn](https://www.linkedin.com/in/webartifex).
 

static/installation/README.md

@@ -0,0 +1,3 @@
+This folder contains screenshots
+used to describe the installation of a Ubuntu
+inside a VirtualBox machine.