SQLite升级数据库:

SQLiteOpenHelper子类关键代码:

public class MyDataHelper extends SQLiteOpenHelper {

    Context mcontext;

    public static final String CREATE_BOOK = "create table book ("

            + "id integer primary key autoincrement, "

            + "author text, "

            + "price real, "

            + "pages integer, "

            + "name text)";

    public static final String CREATE_BOOKCAT = "create table book_cat ("

            + "id integer primary key autoincrement, "

            + "author text, "

            + "price real, "

            + "pages integer, "

            + "name text)";

    public MyDataHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int

            version) {

        super(context, name, factory, version);

        mcontext = context;

    }

    @Override

    public void onCreate(SQLiteDatabase db) {

        db.execSQL(CREATE_BOOK);

    }

    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        switch (oldVersion){

            case :

                db.execSQL(CREATE_BOOKCAT);

                Log.e("db", "执行创建bookcat");

            case :

                db.execSQL("alter table book add column cat_id integer;");

                Log.e("db", "执行在book表中增加列");

            default:

        }

    }

}