1) When you are loading Data from previously loaded table in QlikView Script, you should use Resident Load
2) If you not drop the EXPTemp, there are two tables in the data model associated (Linked) with Field Ename
3) If you don't rename the Field Employee_number to Emp_number, the two tables would be concatenated automatically as in QlikView Script, this tables having same field name and same number of columns...Also when you drop the First Table, the 2nd Table which is now a part of 1st table will also be dropped, so you don't have data in your data model..
Hope this will help
Let there be two Tables as
Now if you load this two tables in script there will be three association key as OrderID,DeliveryDate and Status.
Now if You want to Join them only on OrderID then rename the DeliveryDate and Status.
Resident load is also used to reuse already in-memory loaded tables.
Mainly this is been used in transformation, Calculation, using Qlikview functions with Select query etc