private Cursor queryTransactionsCursor() {
    final Query query =
        Query.create()
            .projectionLocalId(Tables.Transactions.ID)
            .projection(Tables.Transactions.PROJECTION)
            .projection(Tables.Categories.PROJECTION);

    return query(TransactionsProvider.uriTransactions(), query);
  }
  private Transaction insertTransaction(Category category) {
    final Transaction transaction = new Transaction();

    if (category != null) {
      transaction.setCategory(category);
    }

    insert(TransactionsProvider.uriTransactions(), transaction);
    return transaction;
  }