What is a Purchase Requisition?

A Purchase Requisition is a method by which Goods/Services can be Purchased from a Supplier. In Oracle a Purchase Requisition is routed for Approval using Workflow engine. Once approved, this Requisition is often converted to RFQ (Request for Quotation). A Purchase Requisition is usually generated by User Departement or the personnel who are actually going to use the goods or services received from the Requisition. 

OAF Switcher Region: How to use it?

A Switcher region can be used to dynamically switch between the items to be displayed in a table or region.
This is similar to a CASE Statement in SQL. Depending on the input to the Switcher Region, it will display the items under the region.
Lets say, we have a requirement where we need to display Delete Icon as Enabled when Employee is In-Active and Delete Icon as Disabled when Employee is Active as shown below.

To Achieve this, We need to Create a Switcher Region in the Table where you want to display the Delete Icon. If you are using an Advanced Table, Follow the below Steps.
In the VO which populates these rows, make the following changes,

1. Create a Pseudo Column in the Query which returns "Delete_Disabled" or "Delete_Enabled" based on the Status value "Active" or "In-Active".
2. Once the SQL Statement is modified in the Query, DeleteSwitch Item is going to is going to return one the se 2 attributes as Inputs to Switcher Region ("DeleteDisabled" or "DeleteEnabled")

                                        
Now make the following changes in Page or Region

1. Create a New Column under Advanced Table where you want this Delete Icon to be displayed.
2. Right Click on the New Column that was created and Select New -- Switcher

3. Set the following Properties to the Switcher Region.

          ID: DeleteSwitcher
          Region Style: Switcher
          View Attribute: DeleteSwitcher

4. You will notice a new <case> item being created under the Switcher Region.

5. Set the following properties to the First Case Item.
          ID: DeleteDisabled
          Item Style: image
          Prompt: Delete
          Image URL: deleteicon_disabled.gif
          Rendered: True

6. Right Click on Switcher Region and Select New -- Case
7. For the New Item, Set the following Properties

          ID: DeleteEnabled
          Item Style: image
          Prompt: Delete
          Image URL: deleteicon_enabled.gif
          Rendered: True

8. Make sure you are giving the ID of the Item exactly matching with the View Attribute value being returned    by the DELETE_SWITCHER in the Sql Query of VO
9. Test run you page and you will notice that records with Status as "Active" have the Delete Icon Disabled and Status as "In-Active" have the Delete Icon Enabled.

OAF Error: The search cannot be executed because the table has pending changes that would be lost.

If you are getting the above error message while trying to Query a Region in OAF. Add the below simple code in the Controller of the Region/Page after you call the AMMethod.

OAF Error Message:

"The search cannot be executed because the table has pending changes that would be lost"

OAAdvancedTableBean table = (OAAdvancedTableBean) webBean.findChildRecursive ("CustomersAdvTable");
        // When handling a user initiated search, we always need to execute
        // the query so we pass "false" to queryData().
  table.queryData(pageContext, false);

Check the below screenshot to check how I used the above code.

Source: Jaiswal Neelmani
http://jneelmani.blogspot.com/2009/11/oaf-search-cannot-be-executed-because.html