java - 使用 SQLiteOpenHelper 时进行 JOIN 查询的最佳方法是什么

Question

我目前正在这样做。

有更好的方法吗？

public Cursor selectRostersForTeam(Activity activity, int teamId) {

    final String MY_QUERY = "SELECT r." + _ROSTER_ID + ", t." + _TEAM_ID + ", t." + TEAM_NAME + ", t." + TEAM_SEASON_WINS + ", t." + TEAM_SEASON_LOSSES + ", t." + TEAM_CHAMPIONSHIP_WINS + ", j." + _TEAMS_ROSTERS_ID + " FROM " + TABLE_TEAM + " AS p" + " JOIN " + TABLE_TEAMS_ROSTERS + " j ON (r." + _ROSTER_ID + " = j." + TEAMS_ROSTER_ROSTER_ID + ") " + " JOIN " + TABLE_TEAM + " ch ON (j." + TEAMS_ROSTER_TEAM_ID + " = t." + _TEAM_ID + ") WHERE j. " + TEAMS_ROSTER_TEAM_ID + " = " + teamId + ";";



    SQLiteDatabase db = getReadableDatabase();

    Cursor cursor = db.rawQuery(MY_QUERY, null);

    activity.startManagingCursor(cursor);

    return cursor;
}

Answer 1

rawQuery() 的替代方案是 query()，但它不是为连接而设计的。

如果您认为您的加入足够重要，您可以 create a view出来，然后在表中使用它进行 query()。

<小时/>

注意:建议将 teamId 之类的值作为参数传递，而不是将它们格式化为查询字符串:

rawQuery(..._TEAM_ID + " = ?", new String[] { Integer.toString(teamId) });