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JoinCursor. The join cursor configuration is specified when calling
To create a configuration object with default attributes:
JoinConfig config = new JoinConfig();
To set custom attributes:
JoinConfig config = new JoinConfig(); config.setNoSort(true);
Joined values are retrieved by doing a sequential iteration over the
first cursor in the cursor array, and a nested iteration over each
following cursor in the order they are specified in the array. This
requires database traversals to search for the current datum in all the
cursors after the first. For this reason, the best join performance
normally results from sorting the cursors from the one that refers to
the least number of data items to the one that refers to the
most. Unless this method is called with true,
does this sort on behalf of its caller using the
If the data are structured so that cursors with many data items also
share many common elements, higher performance will result from listing
those cursors before cursors with fewer data items; that is, a sort
order other than the default. Calling this method permits applications
to perform join optimization prior to calling
noSortwhether automatic sorting of the input cursors is disabled.