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

That VERSION identifies the current database version, and database fields can be modified and expanded in onUpgrade.

Answer 2

VERSION represents the database version, which changes when the database is updated. There may be different software versions, their database versions are also different, and the fields in the database are also different