android - 关于SQLite数据库:SQLiteOpenHelper的构造函数参数VERSION。

Question

/*public class TanngoBaseHelper extends SQLiteOpenHelper {

private static final int VERSION = 1;
private static final String DATABASE_NAME = "tanngoBase.db";

public TanngoBaseHelper(Context context) {
    super(context, DATABASE_NAME, null, VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("create table" + TanngoTable.NAME + "(" +
            " _id integer primary key autoincrement," +
            TanngoTable.Columns.UUID + "," +
            TanngoTable.Columns.WORD + "," +
            TanngoTable.Columns.MEAN + "," +
            TanngoTable.Columns.DATE + "," +
            TanngoTable.Columns.SOLVED +
            ")"
    );
}

@Override
public void nUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

}*/
public class TanngoBaseHelper extends SQLiteOpenHelper {

private static final int VERSION = 2;
private static final String DATABASE_NAME = "tanngoBase.db";

public TanngoBaseHelper(Context context) {
    super(context, DATABASE_NAME, null, VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("create table " + TanngoTable.NAME + "(" +
            " _id integer primary key autoincrement, " +
            TanngoTable.Columns.UUID + ", " +
            TanngoTable.Columns.WORD + ", " +
            TanngoTable.Columns.MEAN + ", " +
            TanngoTable.Columns.DATE + ", " +
            TanngoTable.Columns.SOLVED +
            ")"
    );
}

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

}

Answer 1

Versi itu mengenal pasti versi pangkalan data semasa, yang boleh diubahsuai dan diperluas dalam medan pangkalan data dalam Onupgrade.

Answer 2

VERSION mewakili versi pangkalan data, yang berubah apabila pangkalan data dikemas kini. Mungkin terdapat versi perisian yang berbeza, versi pangkalan datanya juga berbeza, dan medan dalam pangkalan data juga berbeza