SQuery Join

Hello Franck,

I have been reading through the Join code, tidying things up a 
bit.  But I have also substantially cut down the provided 
functionality in the last commit.

In particular, Joins now can only go one level from the many 
table.  And we can only go from the many to the One.  So
   new SQuery(Department).join(Employee) // NOT allowed.
I'm not sure the above made that much sense anyway.

With that gone, so is Distinct processing. (I might have over purged 
here. svn diff is your friend.)

I have also changed the default SelectMode to be NORMAL, not 
NONE.  Seems more normal to me.  (Change it back if you think NONE is better.)

I don't think that I have removed any very useful functionality.

The previous semantics were a bit woolly IMHO.  To do full joins one 
really needs to get control of the table aliases which we do not want 
to do now.  And this affects the API, which we need to keep 
clean.  Chains of references should really have the chain specified 
explicitly rather than infer it.  But I would rather just not do it 
at all for now.

The important OUTER join code is also simpler to write if there is 
only one level, many table to one table.  We need to put the 
conditions in the "ON" clause rather than the WHERE.

(Remember that one can always write raw SQL for unusual cases.  Goal 
is to keep SimpleOrm simple.)

Another priority is to clean up the code around SPreparedStatement, 
SSessionDatabase and SQuerySql.  It is quite messy at the moment, 
control bounces all over the place.  I have removed some redundant 
state from SPreparedStatement, but more needs to be done.  Once it is 
all clean, then more could be added.

(I also started working on sub selects.  So that we can write
         SQuery<Employee> subQ2 = new SQuery<Employee>(Employee.meta)
           .eq(Employee.MANAGER, Employee.NAME,  "One00");
to retrieve employee's whose managers  name is One00.  But it is not 
complete, and I should probably not have started it.  Actually, I 
have just deleted it -- need to stay focused.  I think that I had had 
similar code in an early version of SimpleOrm, before SQuery.)

And there is also the problem of IS NULL vs EQ that remains 
outstanding.  (eq(field, null) should automatically generate IS NULL 
code, we should hide that from the user.  But the test is not really 
isNull, but isEmpty -- Oracle treats "" like 
NULL.  SRecordInstance.isEmpty is probably wrong.)

Please let me know what you think.

Anthony



Dr Anthony Berglas, [email protected]       Mobile: +61 4 4838 8874
Just because it is possible to push twigs along the ground with ones nose
does not necessarily mean that is the best way to collect firewood.


------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/SimpleORM/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/SimpleORM/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:[email protected] 
    mailto:[email protected]

<*> To unsubscribe from this group, send an email to:
    [email protected]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/