Faith Thomas

Briefly summarize 5 things what you have learned in the course so far.   What a database is, why we use a them instead of spreadsheets Basic SQL terms like table/row/column and how they relate How primary/foreign keys work How to join tables, group data, and use subqueries to answer questions. How to make ER diagrams, turn them into tables, and reduce duplication with normalization. List at least 3 questions you still have about databases. When is a join better than a subquery, and when is HAVING better than WHERE? How do I know when to stop normalizing (1NF, 2NF, 3NF) for a real project? Which columns should I index first, and how do I check if the index is actually used?

What is an SQL view.  How is it similar to a table? In what ways is it different (think about primary keys,  insert, update, delete operations) ? A view is a saved select query that acts like a virtual table, so I can query it and join it just like a real table. It is similar to a table because it shows rows and columns and I can use the same select syntax on it. It is different because it does not store data itself, it usually does not have its own primary key, and many views are read only, so insert, update, and delete only work if the view is updatable and maps each row back to one row in a base table. We have completed our study of SQL for this course.  This is not to imply that we have studied everything in the language.  There are many specialized features such as calculating rolling averages, query of spatial data (data with latitude and longitude) coordinates, and more. But take a minute to think about how SQL compares to other programming languages such as J...

SQL has the flexibility to join tables on any column(s) using any predicate (=, >, < ).    Most of the time the join will use equality between a primary and foreign key.   Think of example where joining on something other than keys would be needed.  Write the query both as an English sentence and in SQL.  If you can't think of your own example, search the textbook or internet for an example. English: Match each student to any course that gives more credits than the number of credits the student has already earned SQL: select student.name, student.tot_cred, course.course_id, course.credits from  student join  course on  course.credits > student.tot_cred; What is your opinion of SQL as a language?  Do you think it is easy to learn and use?  When translating from an English question to SQL, what kinds of questions do you find most challenging? This is the first class where I have really focused on SQL. TO be honest, I do find...

Relational database tables and spreadsheets look similar with both having rows and columns.  What are some important differences between the two? A database is structured and enforces rules, while a spreadsheet lets me put almost anything anywhere. Databases can link tables and handle many people editing safely at the same time. They’re also better for large data, with real security and backups, whereas spreadsheets can get messy and break. Installing and configuration a database and learning how to use it is more complicated that just reading and writing data to a file.  What are some important reasons that makes a database a useful investment of time?  It keeps my data accurate and saves changes safely even if something goes wrong. I can ask complex questions with simple queries instead of fighting with formulas. It also supports multiple users and backups so a project can grow without chaos. What do you want to learn in this course that you think will be useful in your...