import com.google.samples.apps.iosched.provider.ScheduleContract.Speakers; //导入依赖的package包/类
/**
 * Updates the session search index. This should be done sparingly, as the queries are rather
 * complex.
 */
static void updateSessionSearchIndex(SQLiteDatabase db) {
    db.execSQL("DELETE FROM " + Tables.SESSIONS_SEARCH);

    db.execSQL("INSERT INTO " + Qualified.SESSIONS_SEARCH
            + " SELECT s." + Sessions.SESSION_ID + ",("

            // Full text body
            + Sessions.SESSION_TITLE + "||'; '||"
            + Sessions.SESSION_ABSTRACT + "||'; '||"
            + "IFNULL(GROUP_CONCAT(t." + Speakers.SPEAKER_NAME + ",' '),'')||'; '||"
            + "'')"

            + " FROM " + Tables.SESSIONS + " s "
            + " LEFT OUTER JOIN"

            // Subquery resulting in session_id, speaker_id, speaker_name
            + "(SELECT " + Sessions.SESSION_ID + "," + Qualified.SPEAKERS_SPEAKER_ID
            + "," + Speakers.SPEAKER_NAME
            + " FROM " + Tables.SESSIONS_SPEAKERS
            + " INNER JOIN " + Tables.SPEAKERS
            + " ON " + Qualified.SESSIONS_SPEAKERS_SPEAKER_ID + "="
            + Qualified.SPEAKERS_SPEAKER_ID
            + ") t"

            // Grand finale
            + " ON s." + Sessions.SESSION_ID + "=t." + Sessions.SESSION_ID
            + " GROUP BY s." + Sessions.SESSION_ID);
}