Different Columns contained in Report Builder are:
1) Data Columns
2) Formula Columns
3) Summary Columns
4) Placeholder Columns
Data Columns:
Data Columns contain the data values for a report.
Data Columns are corresponding to the table columns included in the select list of a query.
Each column is placed in the group associated with the query.
Formula Columns:
Formula Columns performs user-defined computations.
Formula Columns executes a PL/SQL function and must return a value.
Formula Columns can be placed at the Report or Query level.
Formula Columns should not be used to set a parameter’s value.
Formula Columns should not be used to set a parameter’s value.
Formula Columns is denoted by CF_
Summary Columns:
Summary Columns are used for calculating summary information like
1) Sum
2) Average
3) Minimum
4) Maximum
5) Count
6) First
7) Last
8) % of Total
9) Std Deviation
10) Variance
Summary Columns can be placed at the Report or Query level.
Summary Columns is denoted by CS_
Placeholder Columns:
Placeholder Columns are storage areas in the Data Model.
Used for Temporary storage of data for future reference.
Placeholder Columns value can be set in the following places:
1) Before Report Trigger
2) Report-Level Formula Columns
Placeholder Columns can be populated by a Before Report Trigger but are generally populated by a Formula.
Although Placeholders allow PL/SQL to be written within them, they cannot be self-populated, their value must be set by an external program Unit, any attempts at self-population will result in a runtime compilation error. However the Formula assigned to the Placeholder must return a value.
Placeholder Columns is denoted by CP_
Example: At Formula column:
Function CF_1formula return Number is
Begin
If :no_in_stock<10 then
:CP_1:=’Only’||:no_in_stock||’Items left in stock!!’;
End if;
Return 1;
End;
Example at Placeholder column:
Function CP_1formula return Char is
Begin
Return null;
End;