What is Synthetic Key?

Synthetic Keys: when two or more tables have two or more fields in common is called synthetic key. 

Below are the ways to remove synthetic keys

• Join
• Alias
• Concatenated key
• Link table
• Qualify

How are NULLS implemented in QlikView?

The way in which QlikView's associative engine works means Nulls don't really exist in the data it holds, a Null is simply an absence of a data item. For example if a field value is missing we can’t make selection on empty list box. We can replace these null values with our required values (NA, 0, etc…)

What are the restrictions of Binary Load?

Binary load is used only for one application means you are able to read data from only one QVW application and on the above of the set scripts is a restriction. In QlikView data is stored in QVDs but if you are using any QVW application data is loaded in the RAM that’s why it is called as In-Memory analysis tool.

Briefly explain how does QlikView storage the data internally?

QlikView store data in to QVD. QVD have data compression capability. QlikView have better performance compared to other BI because of in memory analytics approach, in built ETL handling capability.

Optimized and UN optimized QVD Load Situations?

Optimized load is much faster and therefore preferable, especially for larger data sets. Optimized loads are possible if no transformations (calculations) are made during the load, and no (almost) filtering is done in a WHERE clause.

The only acceptable filter is using function Exists: 
WHERE Exists (Field) 
So for example this load can't be optimized: 
Load * From ... WHERE Country = 'US' 
But this load can: 
Load * From ... WHERE EXISTS (Country) 

On the other hand, the only time you want the load not to be optimized, is if you load a Mapping table from a QVD file. In this case, Optimized load doesn't quite work, so you want to make the load non-optimized deliberately.

What is Mapping Load & Apply Map ()?

Mapping Load: The mapping prefix is used on a load or select statement to create a mapping table, these tables are different from other tables. They will be stored in separate area of memory and used as mapping tables during script execution. After execution they will automatically drop.

Ex. Mapping (Load Statement/Select Statement) 

Apply Map: used for mapping data from one source to another at load time. 

Ex. Apply map(Map name, expr,[default expr])

QlikView Interview Questions on QlikView Security

Describe Section Access architecture?
What is the difference between Authentication & Authorization in QlikView? And how to implement them?
What is the difference between File System Security vs Section Access?
Explain “Strict Exclusion” while implementing Section Access and what are the implications of not using this option?
How do you implement Section Access on hierarchy based data?