A series of posts in response to Tim Ford’s #EntryLevel Challenge.
“If we offend, it is with our good will. That you should think, we come not to offend, But with good will. To show our simple skill, That is the true beginning of our end. Consider then we come but in despite. We do not come as minding to contest you, Our true intent is. All for your delight We are not here. That you should here repent you, The actors are at hand and by their show You shall know all that you are like to know.” —Quince’s prologue: A Midsummer Night’s Dream
Part I: Getting started with Oracle Database
Part II: What is a Database?
Part III: What is a Relational Database?
Part IV: What is a Database Management System?
Part V: What makes a Database Management System relational?
Leonardo da Vinci said: “Those who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain [where] he is going. Practice must always be founded on sound theory.” How can you competently administer a relational database management system like Oracle if you don’t really know what makes a “relational” database relational or what a database “management” system manages for you? However, if you’re like other I.T. professionals, you won’t be satisfied until you’ve seen an Oracle database management system. I’ll grant that seeing a real system will make it easier for you to understand a few things. Oracle provides a convenient virtual machine (VM) containing a complete and ready-to-use installation of Oracle Database 12c on Linux. All you need to do is to download and install the Oracle VirtualBox virtualization software and then import a ready-to-use VM. The instructions for doing so are at www.oracle.com/technetwork/community/developer-vm. Pick the Database App Development VM option, and follow the download and installation instructions. (I hope you don’t want me to regurgitate the instructions here.) The instructions are short and couldn’t be simpler, because you don’t need to install and configure Oracle Database; rather, you import a prebuilt VM into Oracle VirtualBox. The only difficulty you may experience is that the prebuilt VM is almost 5GB in size, so you need a reliable and fast Internet connection.
If you follow the instructions and fire up the VM, you see the following screen:
Minimize the terminal window that’s hogging the screen, and click the SQL Developer icon in the top row of icons. SQL Developer is a GUI tool provided by Oracle for database administration. The next figure shows what you will see when SQL Developer starts up.
Click Connections, and create a new connection. Give the connection the name “hr” (Human Resources) or any other name you like. Use the following settings:
· Username “hr”
· Password “oracle”
· Connection Type “Basic”
· Role “Default”
· Hostname “localhost”
· Service Name “orcl”
Then click Connect. This is what you’ll see.
Expand the Tables item in the navigation pane on the left. Six tables are shown; click the EMPLOYEES table. The data in the EMPLOYEES table is listed in a full-screen editor, as shown in the following figure. If you like, you can make changes to the data and then either save your changes (commit) or discard them (roll back) using the Commit Changes and Rollback Changes buttons or the F11 and F12 keys.
Now that you’ve gotten your feet wet in the shallow end of the pool, let’s talk a little theory, shall we?
Excerpted from Beginning Oracle Database 12c Administration