How a General Journal Line is related with a Ledger post (GeneralJournalEntry)

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LedgerJournalTable      jourTable, origJornalTable;
LedgerJournalTrans      jourTrans, origJournalTrans;
SubledgerVoucherGeneralJournalEntry jourLink;

    ;
origJornalTable = LedgerJournalTable::findByGeneralJournalEntry(journalEntry);
if(origJornalTable){
        select * from origJournalTrans where origJournalTrans.JournalNum == origJornalTable.JournalNum
            join jourLink where jourLink.GeneralJournalEntry == journalEntry.RecId && origJournalTrans.Voucher ==  jourLink.Voucher;