问题
How can I change or update a data set's query after a parameter has been passed in BIRT report designing?
Detailing:
I've got a query that looks like this:
WHERE ?
That parameter marker can hold different values, after user input parameter, it would look like this e.g.:
WHERE column_name = 1
or
WHERE column_name = 2
or even
WHERE column_name IN (1,2)
I created a Report Parameter(RP) for that Data Set Parameter(DSP) and after trying for hours, I couldn't get to change it.
I tried:
- Creating all sorts of javascript expressions on both, RP and DSP
- Creating a RP that would change the value of the first RP and back to previous step
- Editing the Property Binding, though I couldn't figure it out how exactly it should be done. Just to make it clear, I'm designing a report and not integrating the runtime to an existing application. I hope this is clear enough, I'm still editing the question so if you need more information just let me know.
Thanks
回答1:
Assuming that you are on an Oracle DB (other systems may behave differently) you should be aware that a bind variable (in JDBC speech: the question mark) can replace a scalar value only, e.g. a string or a number.
But you want something like a list of numbers as input. Thus a bind variable won't help you in this case.
Probably the easiest way to achieve what you want is this:
In your query, write:
WHERE column_name in (1) -- $REPLACE_THIS$
Note that I am using a comment in the query as a marker.
Then, in the query's beforeOpen event, modify the query text like this:
// construct a comma-separated string representation of your list
// based on your report parameter (exercise left to the reader)
// var replacement = my_to_sql_csv(params["my_report_parameter"].value);
// for demonstration use:
var replacement = "1,2";
// modify the `IN` expression inside the SQL
this.queryText = this.queryText.replaceAll("(1) -- $REPLACE_THIS$", "(" + replacement + ")";
That's it.
来源：https://stackoverflow.com/questions/28070809/updating-data-set-query-after-parameter-input-in-birt