Data changes over time and, after every new load, cached datasets must be refreshed. Express accesses your RDBMS the first time you create a dashboard, and then stores a copy of the results for later analysis. Whenever the data changes on the data warehouse, Express must reload an updated copy. This can be done manually or on a schedule.
The manual process is the same as we used in the preceding recipe; just select database connection, tables, and fields; in this recipe, we will look at how the whole procedure can be automated to run unattended.
When automating schedules in Express, the time is always set according to GMT clock. This means that the daylight saving time is not taken into account, and your loads will run at a different time in summer (in case your country observes DST). For example, a 2 A.M. GMT load would run at 3 A.M. in Rome during winter, and 4 A.M. during summer.
Note
Bookmark this URL http://www.timeanddate.com/time/dst/events.html just in case, and be prepared to receive nightly calls…
To set a schedule:
- Open Express and go to your team main page.
- Move the cursor to Vehicles Co2 emissions, click on the Refresh data option.
- From the drop-down menu, choose Set Schedule.
- In the Select a schedule below dialog, click on the radio button labeled Weekly.
- Change the day to Sunday in the first dropdown and the hour to 3 A.M. in the second (or any time you prefer).
- Press the OK button, the schedule is now set. It will automatically trigger next Sunday at 3 A.M. GMT.
When trigger fires, the data will be loaded from the source database and the dataset cache will be recreated.
To modify the schedule, click on the round clock icon next to the dashboard name and press the Modify button.