Android SQLite API
There are a number of different ways in which the Android API makes it fairly easy to use our app's database. The first class we need to get familiar with is SQLiteOpenHelper
.
SQLiteOpenHelper and SQLiteDatabase
The SQLiteDatabase
class is the class that represents the actual database. The SQLiteOpenHelper
class, however, is where most of the action takes place. This class will enable us to get access to a database and initialize an instance of SQLiteDatabase
.
In addition, the SQLiteOpenHelper,
which we will extend in our Age Database app, has two methods to override. First, it has an onCreate
method, which is called the first time a database is used, and it therefore makes sense that we would incorporate our SQL in which to create our table structure.
The other method we must override is onUpgrade,
which, you can probably guess, is called when we upgrade our database (ALTER
its structure).
Building and executing queries
As our database structures become more complex...