[SCBCD 5.0] Simplified (reduced) SELECT clause form

[Mikalai Zaikin]

Howdy !

I've seen in some places the reduced form of SELECT clause, like :

em.createQuery("FROM User u WHERE u.name=:name AND u.pass=:pass")

while the "full" form defined by spec is as follows:

em.createQuery("SELECT u FROM User u WHERE u.name=:name AND u.pass=:pass")

So, the question is: where this "simplified" form of SELECT came from ? Is id defined in EJB 3.0 spec, maybe I overlooked it ?

Thanks,
MZ

[Edvins Reisons]

Hello Mikalai,

don't know about the source of this strange abbreviation of queries, but the persistence specification is 100% precise (see 4.14, Query Language BNF):

 
select_statement ::= select_clause from_clause [where_clause] [groupby_clause]
[having_clause] [orderby_clause]
 
select_clause ::= SELECT [DISTINCT] select_expression {, select_expression}*

which means that the SELECT clause is NOT optional, and anybody who writes and implements a query without SELECT (JBoss server and tutorials come to mind ), is deviating from the spec.

[Yevgen Bushuyev]

That's hibernate

[Mikalai Zaikin]

Originally posted by Yevgen Bushuyev:
That's hibernate

Yevgen, thanks a lot !

AFAIK, JBoss uses Hibernate as JPA provider, so simplified SELECT queries are Ok for JBoss, but not Ok for other servers...

[Rizwan Mohammad]

I have used this form of queries(i.e without select) while working with hibernate. In those cases it returns all entities mentioned in FROM clause.
According to ejb3.0 spec both select and from clauses are mandatory.
May be JBoss server support this form of queries as extra benefits. But such queries definitely will not be portable across application servers.