Your company assigns three possible credit ratings to customers: Poor, Good, and Excellent (represented numerically by 1, 2, and 3). The DBA has just added a RATING column to the CUSTOMERS table and has asked you to add an item to your form so that data entry clerks can populate the RATING column. To restrict data entry clerks to one of these three values, you decide to create a radio group for the Rating item. With the Customers block selected in the Layout Editor, you use the radio button to create three radio buttons on the canvas. You then set the labels (Poor, Good, and Excellent) and values (1, 2, and 3) for the radio buttons. You set the name of the radio group to RATING, its Data Type to Number, and its Database column to Rating.
You run the form to test it. When you execute a query, however, no records are returned, although there are many customer records in the database.
What can you do to make the query return the records?
A.
Set the Mapping of Other Values property for the radio group to Null.
B.
Create a fourth radio button for an undetermined credit rating and leave its value blank.
C.
Create a fourth radio button for an undetermined credit rating and explicitly set its value to Null.
D.
Choose a different type of input, because radio groups do not allow query of Null values.
Explanation:
Oracle 9i: Forms Developer Build Internet Application M8-P23 Handling Other Values in a Radio Group
If the base table column for a radio group accepts values other than those associated with your radio buttons, you must use one of the following methods to specify how you want to handle the values:
Ignore other values (by leaving the radio group’s Mapping of other Values properly blank) Associate the other values with one of the existing radio buttons (by naming the associated) value of the button in the Mapping of Other Values property) Note: Ignoring other values results in the entire row being ignored during query processing. NULL Values in a Radio GroupA radio group can treat NULL as a valid value. You should account for the NULL case, if your base table column allows them. Do this in one of the following ways:
Use the Manager of Other Values properly to implicitly NULL to a radio button.
Assign the NULL to its own button.
Note: To assign a NULL value, leave the Radio Button Value property blank.