Fixed behavior on NULL foreign keys

Instead of using a simple INNER JOIN, like:

SELECT a,b,rel.c FROM table1, table2 WHERE (table1.smthing =
table2.smthing)

which doesn't show row where foreign keys are NULL, allow use of LEFT
JOIN like:

SELECT a,b,rel.c FROM table1 LEFT JOIN table2 ON table1.smthing =
table2.smthing

The trick works also for multi-relational tables.
Just remember to use the new API setJoinMode.

Signed-off-by: DaNiMoTh <jjdanimoth@gmail.com>

Task-number:QTBUG-8217
Reviewed-by:Michael Goddard
Reviewed-by:Charles Yin

Merge-request: 2576
Reviewed-by: Charles Yin <charles.yin@nokia.com>
(cherry picked from commit c4280dbd9bb37cca21d007f5f8b9217f80b44043)

Change-Id: I349f9418e4859923977942add59872b000cac2c5
Reviewed-on: http://codereview.qt.nokia.com/1853
Reviewed-by: Charles Yin <charles.yin@nokia.com>

0 files changed, 0 insertions, 0 deletions