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

那个VERSION标识了当前数据库版本，可以在onUpgrade中进行数据库字段的修改和扩充。

Answer 2

VERSION代表了数据库的版本，在更新数据库的时候发生改变。 可能会有软件版本不同 他们的数据库版本也是不同的，数据库里的字段也是不同的