...
This will start the JDBC Server on port 2078.
Example SQL queries
Miscellaneous
Rolling Barrel
When the FEWS JDBC Server is started, the OC rolling barrel configuration will not be used. Instead the Rolling Barrel will run once a day at 02:00 GMT. After the FEWS Rolling Barrel, the compact Database script (only for MS ACCESS databases) will also be executed automatically.
(Java) JDBC Clients, Timezones and DayLightSaving conversion
FEWS stores timeseries with timestamp in GMT, without DayLightSaving (DLS) conversion.
JDBC Client applications like DBVisualizer adopt timezone settings from the (local) Operating System.
This means that data is converted (from FEWS GMT) to local timezone. When DLS conversion is active, a query on data from the night that DLS is switched (zomertijd to wintertijd, when clock is set back a hour) results in 'double' timeseries records between 2:00 and 3:00 AM.
The JVM for the JDBC client (like DBVisualizer) can be started with an extra commandline option, and forces timezone setting for the JVM rather tha adopting it form the local OS. This commandline option looks like:
-Duser.timezone=GMT
or
-Duser.timezone=GMT+1
or
-Duser.timezone=GMT-5
and so on...
When starting DBVisualizers JVM with -Duser.timezone=GMT results are in GMT, without DLS conversion.
Another noticeable issue:
The FEWS-JDBC Server, started as described above, in a standalone manner, has a (hardcoded) timezonesetting of GMT.
The FEWS-JDBC Server can also be started embedded from the FEWS Explorer using F12 key. In the latter case it runs in the timezone set for the FEWS Explorer!
This means that a standalone FEWS-JDBC Server and a embedded FEWS-JDBC Server started from fi. a FEWS Explorer with Dutch timezone settings, may give different timestamps on (the same) timeserie values with a shift up to 2 hours, depending on DLS conversion.
Known issues
- java.sql.SQLException: java.net.MalformedURLException: no protocol....
This is an exception that occurs due to a bug in DBVisualizer. Check whether DBVisualizer OR the vjdbc drivers are located in directories that contain spaces in their path. Move them to a directory path without spaces to solve this issue.