Hi Michael,
Thanks for following up on this. More below....
On 3/22/2012 3:50 PM, Michael Bouschen wrote:
> Hi Linda,
>> Hi Michael,
>>
>> On 3/19/2012 3:26 PM, Michael Bouschen wrote:
>>> Hi Linda,
>>>> Hi Christian,
>>>>
>>>> On 3/19/2012 6:54 AM, Christian Romberg wrote:
>>>>> Dear group,
>>>>>
>>>>> While investigating how to parse queries like this (all page/chapter references refer to EDR 2.1, Dec 19th, 2011):
>>>>>
>>>>> SELECT p
>>>>> FROM Person p, in(pc.firstnames) n
>>>>> WHERE n = 'Joe'
>>>>>
>>>>> (firstnames is a List<String>)
>>>>>
>>>>> I came across the following example provided in the spec, which is related in structure:
>>>>>
>>>>> section 4.4.4, p. 153:
>>>>>
>>>>> SELECT i.name <http://i.name>, VALUE(p)
>>>>> FROM Item i JOIN i.photos p
>>>>> WHERE KEY(p) LIKE ‘%egret’
>>>>>
>>>>> I looked at the BNF how this is parsed, and did not find any derivation for the FROM clause:
>>>>>
>>>>> where_clause ::= WHERE conditional_expression
>>>>> conditional_expression ::= conditional_term
>>>>> conditional_term ::= conditional_factor
>>>>> conditional_factor ::= conditional_primary
>>>>> conditional_primary ::= simple_cond_expression
>>>>> simple_cond_expression ::= like_expression
>>>>> like_expression ::= string_expression LIKE pattern_value
>>>>>
>>>>> So eventually I end up with 'string_expression', from which I can not derive a 'qualified_identification_variable'
>>>>>
>>>>> string_expression ::=
>>>>> state_field_path_expression |
>>>>> string_literal |
>>>>> input_parameter |
>>>>> functions_returning_strings |
>>>>> aggregate_expression |
>>>>> case_expression |
>>>>> function_invocation |
>>>>> (subquery)
>>>>>
>>>>> Did I miss something, or is there actually a rule missing in the grammar for this?
>>>>
>>>> Yes, you are right. The problem is that composable_qualified_identification_variable
>>>> is currently assumed to not designate a state field, which it should.
>>>>
>>>> Not sure yet what the best fix for this is in the grammar yet.
>>> would it work if we add composable_qualified_identification_variable as an additional alternative in string_expression
>>> (and datetime_expressio etc.):
>>>
>>
>> I believe so, but I think we have to go further. I.e., I think we need to support this also
>> in in_expression, function_arg, case_operand, aggregate_expression, and entity_or_value_expression.
>>
>> Do you agree?
>
> yes agreed. The same holds true for orderby_item, correct?
>
Yes, orderBy_item needs to be covered as well.
I am hesitating about adding composable_qualified_identification_variable
to state_field_path_expression though, because a key may often not be a
state field of the object that is the map value. I'm also concerned
about the order-by rules. E.g.,
@Entity
public class Company {
@Id int id;
...
@OneToMany // map key is division name
Map<String, VicePresident> organization;
The following query shouldn't work, because the key is
not part of the result.
SELECT vp
FROM Company c JOIN c.organization vp
WHERE vp.reports > 100
ORDER BY key(vp)
So, I was thinking of just either adding composable_qualified_identification_variable to
the needed places (ugly) or defining another non-terminal, e.g.,
generalized_state_expression::= state_field_path_expression | composable_qualified_identification_variable.
What do you think?
regards,
-Linda
> So maybe we extend state_field_path_expression and add composable_qualified_identification_variable as an alternative:
>
> state_field_path_expression ::=
> general_subpath.state_field |
> composable_qualified_identification_variable
>
> Regards Michael
>
>>
>> regards,
>>
>> -Linda
>>
>>> string_expression ::=
>>> state_field_path_expression |
>>> composable_qualified_identification_variable |
>>> string_literal |
>>> ...
>>>
>>> Regards Michael
>>>
>>>>
>>>> Thanks for pointing this out.
>>>>
>>>> -Linda
>>>>
>>>> \
>>>>>
>>>>> Thank you!
>>>>>
>>>>> Christian
>>>>>
>>>>>
>>>>> --
>>>>> Christian Romberg
>>>>> Chief Engineer| Versant GmbH
>>>>> (T) +49 40 60990-0 <tel:%2B49%2040%2060990-0>
>>>>> (F) +49 40 60990-113 <tel:%2B49%2040%2060990-113>
>>>>> (E) cromberg_at_versant.com <mailto:cromberg_at_versant.com>
>>>>> www.versant.com
>>>>> <http://www.google.com/url?q=http%3A%2F%2Fwww.versant.com%2F&sa=D&sntz=1&usg=AFrqEzeeEBc_gN_8mxtt8xDB0tjXDXQVlw>|
>>>>> www.db4o.com
>>>>> <http://www.google.com/url?q=http%3A%2F%2Fwww.db4o.com%2F&sa=D&sntz=1&usg=AFrqEzdo3Q40RwKQPBtnPIuBYQd1diFxJQ>
>>>>>
>>>>> --
>>>>> Versant
>>>>> GmbH is incorporated in Germany. Company registration number: HRB
>>>>> 54723, Amtsgericht Hamburg. Registered Office: Halenreie 42, 22359
>>>>> Hamburg, Germany. Geschäftsführer: Bernhard Wöbker, Volker John
>>>>>
>>>>> CONFIDENTIALITY
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>>>>>
>>>>>
>>>>>
>>>
>>>
>>> --
>>> *Michael Bouschen*
>>> *Prokurist*
>>>
>>> akquinet tech_at_spree GmbH
>>> Bülowstr. 66, D-10783 Berlin
>>>
>>> Fon: +49 30 235 520-33
>>> Fax: +49 30 217 520-12
>>> Email: michael.bouschen_at_akquinet.de
>>> Web: www.akquinet.de <http://www.akquinet.de>
>>>
>>> akquinet tech_at_spree GmbH, Berlin
>>> Geschäftsführung: Martin Weber, Dr. Torsten Fink
>>> Amtsgericht Berlin-Charlottenburg HRB 86780 B
>>> USt.-Id. Nr.: DE 225 964 680
>
>
> --
> *Michael Bouschen*
> *Prokurist*
>
> akquinet tech_at_spree GmbH
> Bülowstr. 66, D-10783 Berlin
>
> Fon: +49 30 235 520-33
> Fax: +49 30 217 520-12
> Email: michael.bouschen_at_akquinet.de
> Web: www.akquinet.de <http://www.akquinet.de>
>
> akquinet tech_at_spree GmbH, Berlin
> Geschäftsführung: Martin Weber, Dr. Torsten Fink
> Amtsgericht Berlin-Charlottenburg HRB 86780 B
> USt.-Id. Nr.: DE 225 964 680