As with most JDBC drivers, there is a server and a client component to the JDBC driver.
The server is designed to run as a Servlet on the Carte server, the Pentaho Data Integration server or Pentaho Business Analytics platform. At the time of writing only Carte is supported.
The client JDBC driver consists of the kettle-core.jar library (500kB) which has dependencies against Apache Commons HTTP Client (300kB) and Apache Commons VFS (300kB) only.
The carte configuration file accepts a <services> block that can contain <service> elements with the following sub-elements:
- Grouping is done using a "Memory Group By" step which keeps all the groups in memory. If you expect large amounts of groups to be used, watch your memory consumption on the server. We're using the "memory group by" step to avoid doing a costly sort on the data.
- Prepared statements are not yet supported which will limit the usefulness of the driver in 3rd party tools.
- It is not possible to specify the same field twice in the same SELECT clause. (for whatever reason you might do that)
Since SQuirrel already contains most needed jar files, configuring it simply done by adding kettle-core.jar as a new driver jar file
The following jar files need to be added:
- commons HTTP client
- commons code
- commons lang
- commons logging
- commons VFS (1.1)
The following things are next on the agenda:
- Caching of services data in memory with validity time-out
- Caching of queries in memory with validity time-out
- prepared statements
- writing to a service transformation (INSERT INTO)