XQuark Bridge - Release Notes
Version 1.1 beta 1
News
Extraction/XQuery
- Support of the "W3C Working Draft 12 November 2003" XQuery syntax.
- Support for functions (views) and modules.
- Support for computed constructors.
- Enhanced support of standard XQuery serialization allowing (as much as
possible) the user to get uniform and conformant output from the various RDBMS supported.
- New abstract JDBC types supported (BINARY, VARBINARY, LONGVARCHAR,
LONGVARBINARY, BLOB, CLOB) with some limitations (see below).
- Preliminary support of conditional expressions in the
return
clause.
Mapping language
- Two table mappings associated to the same element can now reference each other. This provides better support for storing
n-n relations.
- Syntax: the generator "method" attribute is replaced by a more explicit
"class" attribute.
- JDBC batch size control enabled via the "map" element attribute
"batchSize".
- Generators can now be associated to attribute elements.
- A built-in generator was added for simple key generation.
Supported databases versions
Oracle
This software has been thoroughly tested with Oracle 8.1.7 and its
associated JDBC thin driver. It is known to work with Oracle 9i,
provided that the 9i JDBC driver is used.
The driver can be downloaded at
http://otn.oracle.com/software/tech/java/sqlj_jdbc/content.html
(an Oracle Technology Network login is needed to access this page).
Microsoft
This software has been thoroughly tested with MS SQLServer 2000 and
its associated JDBC driver.
The driver can be downloaded at http://www.microsoft.com/sql.
Sybase
This software has been thoroughly tested with Sybase 11.9.2 and the
jConnect5.5 JDBC driver.
The driver can be downloaded at http://www.sybase.com, searching for
jConnect.
Important note: In order to get XQuark Bridge running on
Sybase 11.9.2, the Sybase administrator must setup the Sybase metadata
views using the script located in the file jConnect-5_5/sp/sql_server.sql.
MySQL
This software has been thoroughly tested with MySQL 3.23 and
mySQL-connector-3.0.9.
This driver is included in the distribution.
Known bugs and limitations
Oracle
- Clob and blob not supported (no standard JDBC support in Oracle8.1.7 driver).
XQuery Extraction
- XQuery extraction requires in some cases that table or view rows have a unique ID
(prmary key, rowid or implicit key built from all row columns) to work properly. Wrong results may
otherwise be produced with the following kinds of queries:
- Nested FLWOR expressions. Keys are needed for reconstruction except for
the innermost FLWORs.
- With MySQL, aggregate rewriting introduces group by clauses that may also
collapse duplicate rows.
- MySQL: some complex queries do not work (for instance multiple
some
or every
clauses appearing in disjunctions).
- MySQL/SQLServer/Sybase: Comparison between VARCHAR and CHAR columns does
not consider trailing CHAR blanks. This must be taken into account when writing
where clauses...
- Oracle: predicates including compararisons with '' (empty string) don't
work as expected since '' is equivalent to NULL on this DBMS. Use the exists function
instead. For instance != '' is translated as != NULL by Oracle and is
always evaluated as false (not equivalent to 'IS NOT NULL').