如何从 Oracle NoSQL table 中获取所有行？

Question

如何在 Java 中使用 TableAPI 从 Oracle NoSQL table 获取所有行？ 我可以通过主键值获取记录。示例：

    TableAPI tableH = kvstore.getTableAPI();
    Table myTable = tableH.getTable("myTable");
    PrimaryKey key = myTable.createPrimaryKey();
    key.put("item", "Hat");

    List<Row> myRows = null;
    try {
        myRows = tableH.multiGet(key, null, null);
    } catch (ConsistencyException ce) {
    } catch (RequestTimeoutException re) {
    }
    for (Row theRow: myRows) {
        String itemType = theRow.get("item").asString().get();
    }
    System.out.println(itemType);

但是我无法获取主键值。

Answer 1

要修改您的示例，您可以通过对 table 使用空主键并使用 TableAPI.tableIterator() 方法之一来获取所有行。关于示例的注释，TableAPI.getTable() 将执行远程调用，因此应隐藏和重用 Table 句柄。

TableAPI tableH = kvstore.getTableAPI();
/* 
 * get the Table, but be careful about doing this frequently,
 * as it performs a remote call.
 */
Table myTable = tableH.getTable("myTable");
PrimaryKey key = myTable.createPrimaryKey();

try {

    /* create and use an iterator on the Row value */
    TableIterator<Row> rowIter = tableH.tableIterator(key, null, null);
    while (rowIter.hasNext()) {
        Row row = rowIter.next();
        /* do something */
    }

    /* 
     * Or...
     * create and use an iterator on the PrimaryKey values.
     * This is much faster than fetching the data as well if
     * you only need fields in the primary key.
     */
    TableIterator<PrimaryKey> keyIter =
              tableH.tableKeysIterator(key, null, null);
    while (keyIter.hasNext()) {
        PrimaryKey key = rowIter.next();
        /* do something */
    }
} catch (FaultException fe) {
}