To add a null value, use null() or an empty string ''
Do you load the entire application? It depends how long the load takes. If the whole app loads in a few minutes then I wouldn't bother with an incremental load as the QlikView server reloads the app in the background.
Search for Incremental Load for more details.
You can modify the error messages in charts - edit the chart Properties / General / Error Messages
1. This depends on the report/chart you're trying to write. More information is needed to properly answer this question.
2. It is possible to do incremental loads, this is what we do. Here's a nice write up on its usage:
3. Customized error messages are very useful and use them regularly for calculation conditions in my charts, etc.
Right-click on the object you want to specify an error for and go to the General Tab. Click the "Error Messages..." button.
Thank you so much Colin.
The second question i have not asked properly.
While developing the application, daily do we need to reload the application? Because the data is huge, already we are creating set of QVDs through incremental load concept and using those QVDs as input. But while developing the application itself, how can proceed with loads?
You could restrict your application to load only every 1000 lines or so. This can be done in two ways:
- use the debugger and enable the limited load checkbox
- use FIRST n prefix in your LOAD statements. This can be done by way of a variable that contains nothing in production, and FIRST 1000 on development. For example:
LOAD * FROM ...
Or you can create a new Test-set of QVDs that only contains a few days/weeks worth of data.
From the load script your can select Debug mode and then select Limited Load to limit your data to load just 10, 1000, or 10,000 rows from each table so you can develop on a smaller data set.
You can also add a FIRST N prefix to each table load to do this as well, just make sure you remove it when publishing the live app.