Dropdown by index

hi experts,

i am developing webdynpro application with DCs, in my application i have Dropdown list, i want to get values from Backend DB, i am using oracle 10.2

here my Question r.

1. For using Dropdown list which Dropdown list i should use, i mean DD BY KEY or DD BY INDEX.

2. where extractly i should connect the datasource, where i should mapping to all attributes in the datasource to context nodes or attributes.

can i get anycoding how to fill values in dropdown and how to retrive the selected value.

thk u ,

pls help me on this issues.

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vijai