Changing Datasources conflict

[sforgelogin]

While working on a project I created a report template to be used with two slightly different versions of a database. In the report I used a query like:

 

select a.* from table a

 

this returned all the columns for this table, however I only used a few. In one version of the database there was an extra column that was not in the other version, however iReport does not refresh the xml when switching datasources, and I got an error stating that the column could not be found. I think that only putting the fields used in the actual report or refreshing the xml would be a great idea since this type of scenario seems fairly common.

[Giulio Toffoli]

"select *" is never a safe (and good) approach. Select always only the fields your really need: this for two reasons:

1. You are safe is a field you don't use in your report disappear from the table

2. The engine reads only the really needed fields from the datasource, saving memory and time.

 

Giulio

[dsachdev]

You may also need to uncheck: "Automatically retrieve fields" if you are bouncing back and forth between two databases that have differen schemas.