Very nice work!
Thanks,
Rodrigo
-----Original Message-----
From: Dain Sundstrom [mailto:[EMAIL PROTECTED]]
Sent: quarta-feira, 27 de fevereiro de 2002 00:10
To: JBoss-dev; JBoss-user
Subject: [JBoss-user] New EJB-QL compiler (ORDER BY and DynamicQL)
The new EJB-QL compiler is finished and checked in tip. The new compiler
is a complete rewrite in JavaCC, and is much faster, easier to maintain,
and has error messages. I was surprised by the number of errors I found
in the old parser. You guys haven't been pushing the engine enough, so
to give you incentive to test the new engine I've added several new
features.
Error messages:
This is not really a feature but as we didn't have them before it feels
like a feature.
JBossQL:
I actually wrote two compilers a spec compliant EJB-QL compiler and
JBossQL compiler. JBossQL is a superset of EJB-QL which adds support for
ORDER BY. To use JBossQL you override ejb-ql declaration in your
jbosscmp-jdbc.xml file with a jboss-ql element (i.e. just copy the query
element from your ejb-jar.xml file, change ejb-ql to jboss-ql and add
the order by clause. The BNF for order by follows:
JBossQL := select_clause from_clause [where_clause] [order_by_clause]
order_by_clause := ORDER BY order_by_path_expression
( , order_by_path_expression)*
order_by_path_expression := ( numeric_valued_path |
string_valued_path |
datetime_valued_path ) [ASC | DESC]
dynamic-ql:
The new compiler is eye-blink fast, so I added a new query type
dynamic-ql. With dynamic-ql you can generate a JBossQL query and pass it
along with the parameters to the engine to be compiled and execute at
runtime. To use this query you add an ejbSelect method to your bean
with the following signature:
<return-type> ejbSelect<some-name>(String jbossQL, Object[] args)
You must declare the query type in your ejb-jar.xml (required by the
spec; just leave the ejb-ql element empty) and in your jbosscmp-jdbc.xml
file override the impl with an empty <dynamic-ql/> element.
For more info specifying the queries, see the jbosscmp-jdbc_3_0.dtd
Please, post follow-ups in the online forum at
http://main.jboss.org/thread.jsp?forum=46&thread=9743
-dain
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