SQLite升级数据库:

SQLiteOpenHelper子类关键代码:

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 1:
                db.execSQL(CREATE_BOOKCAT);
                Log.e("db", "执行创建bookcat");
            case 2:
                db.execSQL("alter table book add column cat_id integer;");
                Log.e("db", "执行在book表中增加列");
            default:
        }
    }
}