In QlikView you cannot create, update or delete any type of indexes. This is a fact and no suggestion. QlikView will perform at top speed because it handles "indexes" completely automated under the hood.
In effect all fields and all values - both text and numbers are indexed and deduplicated through its symbol table generation. That is why QlikView is so extremely fast in most situations...
The full context of what you heard is likely that creating indexes on your SQL tables will improve the performance of loading data into Qlikview. Qlikview is very efficient but a database without indexes is very inefficient.
Without indexes on tables you would perform constant full table scans.
I am not sure how that would affect performance in Qlikview if you were doing something simple like Load * from table1 but if you put any type of where clause on it the performance would suffer terribly.
It's poor design not to have a primary key or clustered index on a SQL table and those tables without clustered indexes are called heaps. Without indexes there is no way for you to search directly for John Smith, it must go down every single row looking for John Smith.
Hopefully you have a DBA who ensures the database servers are properly configured and maintained.
