R.R. Donnelley Senior Software Engineer Interview Questions and Answers

Pivoting columns in SQL involves transforming rows into columns to display data in a different format.

• Use the PIVOT keyword in SQL to pivot columns

• Specify the columns to pivot on and the values to display in the new columns

• Aggregate functions like SUM, AVG, COUNT can be used with PIVOT

• Example: SELECT * FROM table_name PIVOT (SUM(value_column) FOR pivot_column IN ('value1', 'value2', 'value3'))

Scope of variable in Perl determines where the variable can be accessed.

• Perl has three types of variable scope: global, local, and lexical.

• Global variables can be accessed from anywhere in the program.

• Local variables are declared using the 'my' keyword and can only be accessed within the block they are declared in.

• Lexical variables are declared using the 'state' keyword and can be accessed within the block they ar...read more

Hash is a data structure that stores data in key-value pairs while array is an ordered list of scalar values.

• Hashes are denoted by % symbol and arrays by @ symbol in Perl.

• Hashes are useful for storing and retrieving data quickly based on a unique key.

• Arrays can be accessed using index numbers starting from 0.

• Both hashes and arrays can store different data types such as strings, numbers, and references.

• Example: %ha...read more

CDATA is a way to include special characters in XML data without causing parsing errors.

• CDATA stands for Character Data

• It is used to include data that contains characters that would otherwise be interpreted as XML markup

• CDATA is enclosed in tags

• Example: bold text]]>

OOPs concepts, abstraction vs interface, MVC architecture, stored procedures, joins

• OOPs concepts include inheritance, polymorphism, encapsulation, and abstraction

• Abstraction is hiding the implementation details while interface is a contract that defines the methods that a class must implement

• MVC architecture separates the application into Model, View, and Controller components for better organization and maintenan...read more