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I have dissected many hard drives, and let me tell you - databases can be a sticky and complicated mess! The number of tables... the unusual column names... the linking of tables. It can feel overwhelming! What’s an engineer to do!? Well, do I have a solution for you. VIEWS… These virtual tables make it easy to search your database and avoid those super-long queries. It probably sounds too good to be true, right! Well, it’s not… It’s TRUE. It is! … It is! It is! It is! It is!! The date? In the future. The place? Mars… The mission? Learn about views. To start, suppose we have a table called “Martian Confidential”. This table contains information on every person who is living on the planet. Let’s take a look at the data in the “Martian Confidential” table... Two of its columns contain sensitive information. The salary in Solar credits should not be available to everyone. And the dna_id is extremely sensitive. Unauthorized cloning is a growing problem in the remote colonies. How do we give engineers access to SOME of this data, but not these two columns? By creating a view. The first step in making a view is to write a query returning precisely the rows and columns you want in your view. We have been instructed that it is OK to share all data except the salary and dna_id columns. Execute… To create a view from this data, insert a line above the query. Write “CREATE VIEW” and give your view a name. We will call this view “Martian public”. Then write AS… That’s all there is to it! Run this query… The view is created. You can now treat “Martian_public” as a table. A quick select shows that the confidential data is not present. And look what happens if you try to select the confidential data… You would never know it was there… That data is now a rumor, recognizable only as deja vu and dismissed just as quickly. This is an important benefit of views: Security. By giving engineers access to views instead of all the underlying tables, you control the data they can see. Let us introduce another table to our database: “visitor”. This table holds a list of all people currently visiting Mars. Here is our task: create a view that contains a list of all people on Mars. This view should contain their first name, last name, a unique ID, and their status: Martian or Visitor. We start by writing the query to generate this list. Our first SELECT gives us the information we need from the Martian table. Each person in this table is a “Martian”, so in the SELECT clause include a “Martian” string and call the column containing this string “status.” Execute… This gets us part way there. We also want the names, status, and IDs of the visitors, too. One way to combine two queries is with the “UNION” command. This will combine the results of two SELECT...