Technology Questions

Primary key : a relational database constraint. Primary key consists of one or more columns that uniquely identify a row in the table. For a normalized relation, there is one designated primary key.

Unique index: a physical object that stores only unique values. There can be one or more unique indexes on a table.

Change management is the biggest challenge in each and every industry. After requirements stage when development is started client will come-up with some new changes or enhancements. 

Cross departmental or cross team management – like conflict management between teams. Also individuals. This requires soft skills and smartness. 

Communication problems – In real time this can happen. You might be good in speaking and understanding the English language. BUT sometimes it happens like Different people across the globe speak different style of English. In USA itself Mexico people speak English differently. Romans speak different English. So at initial level to understand the accent can be a challenge but after some time you will become perfect. 

In a correlated query, the outer query is related to the inner query. This means one or more columns in the outer query are referenced. It’s used when the outer queries value is being used by inner query. For example, we need to find which employee had more perks in the current month than they did in the previous month. The correlated subquery is executed for each row of perks information in the parent query to first determine what the perks were for each employee in the previous month. This data, in turn, is compared to perks for each employee in the current month, and only those employees whose perks in the current month were greater that their previous month's perks are returned.

COM is the component Object Model is a system whch creates application which are binary form that is language independent , object oriented ,modular and reusable .

main() method is called by the JVM even before the instantiation of the class, hence it is declared as static.

DB2 use the multiple indexes to satisfy multiple predicates in a SELECT statement that are joined by an AND or OR.