When using several data sources, it might be unclear how the sequence of variables is determined in the prompts screen.
Basically, all variables are listed data source by data source. If the data sources are BEx queries, the sequence per data source can be defined in the BEx Query Designer. In BW, different BEx queries can use the same variable. Such variables get melted in the prompts screen in of Design Studio. This means, although the variable is used in two data sources, it shows up only once in the prompts screen. This is the point where the sequence gets a little bit tricky, and the result might be unexpected. First the list of all melted variables is shown, followed by those variables, which are not melted. The sequence of melted variables is defined by the first data source.
Example
A Bex query Query#1 has three input ready variables The sequence of these variables is set in the BEx Query Designer In this example, the sequence is MAK_VAR_01, MAK_VAR_02 and MAK_VAR_03:
A second Bex query Query#2 also has three input ready variables. Two of them also occur in the first query. The sequence of variables inside this 2nd BEx query is MAK_VAR_03, MAK_VAR_01 and MAK_VAR_04:
A Design Studio application is created and both queries are included, first Query#1 and then Query#2. Furthermore, force prompts screen = true is set:
Please note, that it depends on the sequence of adding the data sources. The list of data sources in the Designer, like shown above, is sorted according to the name. It does not necessarily correspond with the sequence of data sources in the application content file. If you add DS_2 before DS_1, the query in DS_2 is in first position in the application content file and defines the sequence.
Testing this application leads to the following sequence:
The variables MAK_VAR_01 and MAK_VAR_03 are melted and therefore they appear on top of the list. Query#1 is in first position inside the application. In Query#1 MAK_VAR_01 is above MAK_VAR_03 and hence MAK_VAR_01 is in first position. The variables MAK_VAR_02 and MAK_VAR_04 are not melted and therefore they are listed at the bottom. As Query#1 is the first data source, variable MAK_VAR_02 is listed before MAK_VAR_04.
If the sequence of data sources inside the Design Studio application is changed, the sequence of variables changes accordingly:
Still the variables MAK_VAR_01 and MAK_VAR_03 are melted and therefore they appear on top of the list. But now Query#2 is in first position inside the application. In Query#2 MAK_VAR_03 is above MAK_VAR_01 and hence MAK_VAR_03 is in first position. The variables MAK_VAR_02 and MAK_VAR_04 are not melted and therefore they are listed after all melted variables. As Query#2 is now in first position, variable MAK_VAR_04 is listed before MAK_VAR_02.
Design Studio also provides the functionality to overrule this default behavior and define a custom sequence of variables. You can find this function in the application properties:
You can shift the variables using the "Move Up" "Move Down" buttons at the right side. The prompts screen shows the list accordingly: