PeopleSoft Application Engine

Does reading data from a Table for inserting into a new Table via App Engine require an AET table?

Hello,

We have the below mentioned straightforward requirement which needs to be fulfilled via an App Engine:
--> Read data from an inbound Interface Table, call a CI to insert the same into a STaging table.

My question is :
1. Should the data be read from the Table using Do Select & the data stored in the AET table & then called again in PeopleCode for calling the CI?
2. Should all the processing be done in PeopleCode by writing all the "fetch" code in PeopleCode using sqlexec & then call a CI?

Thanks !