Oracle Reports: Fixed format reports delivered with the 11i release were built on this tool. This is the most used tool for reporting on Oracle Applications. Most of reports customizations are built with this tool. Once customized the output of the report can be in Excel (Not group By Report), word, Acrobat documents or text format.

Oracle Discoverer: is an intuitive tool for creating reports and performing on-line analysis. Discoverer uses the EUL (End User Layer), a meta data definition, which hides the complexity of the database from the end user and provides easy to use wizards for creating reports to suit individual needs. The flexibility of this tool allows the user to create cross tab reports that perform like pivot tables in Excel.

Oracle XML Publisher: is a new Oracle tool for reporting. It enables users to utilize a familiar desktop tool, like MS Word or MS Excel, to create and maintain their own report. At runtime, XML Publisher merges the custom templates with the concurrent request extracts data to generate output in RTF, PDF, HTML and EXCEL.

RXi Report: (Variable reports) – variable format reports delivered with the E-Business 11i. With this tool a user has the ability to print the same report with multiple layouts. The user can also choose which columns he requires on a particular report. This tool is most used on Oracle Financials Applications.

FSG Reports (Financial Statement Generator): is a powerful report building tool for Oracle General Ledger. Some of benefits of using this tool are that a user can generate financial reports, and schedule reports to run automatically. The only drawback of this tool is that it is only available for the general ledger responsibility and can be used to see only financial account balances.

Business Intelligence System (BI):
is a set of tools to provide high level information for the managers (decision makers) to run their business such as the profitability of a particular business unit. The information this tool provides helps managers to take the right decision with the daily data that is uploaded on their systems

Fan Trap is a situation while running discoverer reports that return unexpected results due to a group of joined database tables. The most common manifestation of a fan trap occurs when a master table is joined to two or more detail tables independently.
If you use a straightforward SQL statement to aggregate data points here, you may get incorrect results due to fan trap. Now, if you enable fan trap detection in Discoverer and if you use Discoverer to aggregate the data points, Discoverer will never return incorrect results.

Example of Fan Trap:
Consider an example fan trap schema that includes a master folder (ACCOUNT) and two detail folders (SALES and BUDGET), as shown below:
Now let’s say we need to answer the question, “What is the total sales and total budget by account?
Straightforward SQL statement approach:
SELECT Account.Name,
GROUP BY Account.Name;

Account    Sales Budget

Account 1   800   1200

Account 2   130    200

Account 3    600   750

Account 4    600   600

The above results are incorrect, because they are based on a single query in which the tables are first joined together in a temporary table, and then the aggregation is performed. However, this approach causes the aggregates to be summed (incorrectly) multiple times.

Discoverer Approach:

If we run the query in Discoverer interrogates the query, detects a fan trap, and rewrites the query to ensure the aggregation is done at the correct level. Discoverer rewrites the query using inline views, one for each master-detail aggregation, and then combines the results of the outer query.

Here are the results from discoverer which is correct:

Account   Sales   Budget

Account 1  400      400

Account 2  130      100

Account 3  200      750

Account 4  300      200

How to enable fan trap in discoverer?

By default, fan trap detection is always enabled for you. If you want to disable it (however not recommended), you can logon to Discoverer Plus, go to Tools > Options >Advanced Tab and click on ‘Disable fan trap detection’.

How Discoverer handles fan trap?

If a fan trap is detected, Discoverer can usually rewrite the query using inline views to ensure the aggregation is done at the correct level. Discoverer creates an inline view for each master-detail aggregation, and then combines the results of the outer query.

In some circumstances, Discoverer will detect a query that involves an unresolvable fan trap schema, as follows:

  • If the detail folders use different keys from the master for the join

  • If there is a direct join relationship between the detail folders (thereby creating an ambiguous circular relationship)

  • If non-aggregated values are chosen from more than one of the detail folders

  • If more than one detail folder has a separate join relationship to a different master folder

In the above circumstances, Discoverer disallows the query and displays an error message.

Although Discoverer provides many functions for calculation in reports, sometime we require to use custom PL/SQL functions to meet additional Discoverer end user requirements (for example, to provide a complicated calculation). For this we first need to create the functions in database through Toad or other PL/SQL editors.
To access custom PL/SQL functions using Discoverer, you must register the functions in the EUL. When you have registered a custom PL/SQL function, it appears in the list of database functions in the “Edit Calculation dialog” and can be used in the same way as the standard Oracle functions.
Note: To register a PL/SQL function you must have EXECUTE privilege on that function.
You can register custom PL/SQL functions in two ways:
  •  Import automatically, by importing the functions (recommended)
  •  Manually

How to register custom PL/SQL functions automatically:

To register PL/SQL functions automatically you must import them in the following way:
 1. Choose Tools | Register PL/SQL Functions to display the “PL/SQL Functions dialog: Functions tab”.
 2. Click Import to display the “Import PL/SQL Functions dialog”. This dialog enables you to select the PL/SQL functions that you want to import.

3. Select the functions that you want to import. You can select more than one function at a time by holding down the Ctrl key and clicking another function.
4. Click OK.
Discoverer imports the selected functions and displays the function details in the “PL/SQL Functions dialog: Functions tab”. Information about the selected functions is imported automatically. In other words, you do not have to manually enter information or validate the information.
5. Click OK.
The PL/SQL function is now registered for use in Discoverer.

How to register custom PL/SQL functions manually:

To manually register a PL/SQL function for use in Discoverer:
1. Choose Tools | Register PL/SQL Functions to display the “PL/SQL Functions dialog: Functions tab”.
2. Click New and specify the function attributes.
3. Click Validate to check the validity and accuracy of the information you have entered.
4. If the function is invalid, correct the attributes and click Validate again.
5. (Optional) if the function accepts arguments:
a. Display the “PL/SQL Functions dialog: Arguments tab”.
b. On the Arguments tab, click New and specify the argument attributes.
6. Click OK when you have finished defining the function.
The custom PL/SQL function is now registered for use in Discoverer.
It is always recommended to register PL/SQL functions by importing automatically (especially if you have many functions to register), because it is easy to make mistakes when manually entering information about functions. When you import functions, all of the information about each function (for example, names, database links, return types, lists of arguments) is imported.