In this chapter, we went from a super bare-bones database schema that just contained one table to an entire schema containing multiple interdependent tables. We first saw how to create and upgrade multiple tables through overriding the SQLiteOpenHelper class, and then thought about some of the challenges surrounding a database schema with interdependencies. We decided to tackle these challenges by surrounding our database schema and its tables with an army of wrapper methods, designed for both ease of future development, as well as robustness in future data. These wrapper methods included everything from simple add methods, helpful as we were able to conceal the need to constantly request a writeable SQLiteDatabase, to more complex remove methods which concealed all of the functionality needed for enforcing various schema rules.

Then, we actually implemented an Activity class to show off our new database schema and ran through some sample database commands to test their functionality. Though we were able to validate and output the results of all our commands, we realized that this was a pretty verbose and suboptimal way for debugging our sqlite3 database, and so we looked into the Android Debug Bridge (adb) tool. With the adb tool, we were able to open a command-line terminal that then hooked into a running instance of an emulator or Android device, and subsequently, connect to that emulator/device's sqlite3 database. Here we were able to interact with the sqlite3 database in a very natural way by issuing various SQL commands and queries.

Now, the queries that we've seen so far have been pretty elementary, but if necessary, will do the trick for the majority of your application development needs. However, we'll see in the next chapter that by mastering more advanced SQL query concepts, we can enjoy both a substantial performance boost as well as a substantial memory boost in our application!