Multiple choice

Three possible credit ratings are assigned to customers: Poor, Good, and Excellent (represented numerically by 1, 2, and 3). A RATING column was added to the CUSTOMERS table and the DBA was asked to add an item to the form so that data entry clerk can populate the RATING column. To restrict data entry clerks to one of these three values, the DBA decided to create a radio group for the Rating item. With the Customers block selected in the Layout Editor, he used the radio button to create three radio buttons on the canvas. He then set the labels (Poor, Good, and Excellent) and values (1, 2, and 3) for the radio buttons. He set the name of the radio group to RATING, its Data Type to Number, and its Database column to Rating. He then ran the form to test it. When he executed a query, however, no records were returned, although there were many customer records in the database. What can he do to make the query return the records?

  1. Set the Mapping of Other Values property for the radio group to Null.

  2. Create a fourth radio button for an undetermined credit rating and leave its value blank.

  3. Create a fourth radio button for an undetermined credit rating and explicitly set its value to Null.

  4. Choose a different type of input, because radio groups do not allow query of Null values.

  5. None of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Radio groups in Oracle Forms cannot match NULL database values because every radio button must have a non-null value. When records contain NULL in the RATING column, no radio button matches, so queries return no records. The solution is to use a different input type like a list item (poplist) or LOV that can handle NULL values.

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