--- /dev/null
+---
+layout: lesson
+root: ../..
+title: Instructor's Guide
+level: novice
+---
+Relational databases are not as widely used in science as in business,
+but they are still a common way to store large data sets with complex structure.
+Even when the data itself isn't in a database,
+the metadata could be:
+for example,
+meteorological data might be stored in files on disk,
+but data about when and where observations were made,
+data ranges,
+and so on could be in a database
+to make it easier for scientists to find what they want to.
+
+Teaching Notes
+--------------
+
+* The first few sections (up to "Missing Data") usually go very quickly.
+ The pace usually slows down a bit when null values are discussed
+ mostly because learners have a lot of details to keep straight by this point.
+ Things *really* slow down during the discussion of joins,
+ but this is the key idea in the whole lesson:
+ important ideas like primary keys and referential integrity
+ only make sense once learners have seen how they're used in joins.
+ It's worth going over things a couple of times if necessary (with lots of examples).
+
+* The sections on creating and modifying data,
+ and programming with databases,
+ can be dropped if time is short.
+ Of the two,
+ people seem to care most about how to add data (which only takes a few minutes to demonstrate).
+
+
+* Overall,
+ this material takes three hours to present assuming that a short exercise is done with each topic.
+
+* Simple calculations are actually easier to do in a spreadsheet;
+ the advantages of using a database become clear as soon as filtering and joins are needed.
+ Instructors may therefore want to show a spreadsheet with the information from the four database tables
+ consolidated into a single sheet,
+ and demonstrate what's needed in both systems to answer questions like,
+ "What was the average radiation reading in 1931?"
+
+* Some learners may have heard that NoSQL databases
+ (i.e., ones that don't use the relational model)
+ are the next big thing,
+ and ask why we're not teaching those.
+ The answers are:
+ 1. Relational databases are far more widely used than NoSQL databases.
+ 2. We have far more experience with relational databases than with any other kind,
+ so we have a better idea of what to teach and how to teach it.
+ 3. NoSQL databases are as different from each other as they are from relational databases.
+ Until a leader emerges, it isn't clear *which* NoSQL database we should teach.