Technology Questions

DocumentDB is a NoSQL document-oriented database and records saves in key-value pairs. It's same as the other NoSQL document-oriented such as MongoDB.

Cursor is a programming device that allows the SELECT to find a set of rows but return them one at a time. Cursor should be used because the host language  can deal with only one row at a time.

- Free() - A block of memory previously allocated by the malloc subroutine is freed by free subroutine. Undefined results come out if the Pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will take place.

- Realloc() - This subroutine changes the size of the block of memory pointed to by the Pointer parameter to the number of bytes specified by the Size parameter and returns a new pointer to the block. The pointer specified by the Pointer parameter must be created with the malloc, calloc, or realloc subroutines and should not be deallocated with the free or realloc subroutines. Undefined results show up if the Pointer parameter is not a valid pointer.

ALV is Application List viewer. Sap provides a set of ALV (ABAP LIST VIEWER) function modules which can be put into use to embellish the output of a report. This set of ALV functions is used to enhance the readability and functionality of any report output. Cases arise in sap when the output of a report contains columns extending more than 255 characters in length. In such cases, this set of ALV functions can help choose selected columns and arrange the different columns from a report output and also save different variants for report display. This is a very efficient tool for dynamically sorting and arranging the columns from a report output. The report output can contain up to 90 columns in the display with the wide array of display options.

Polymorphism is also achieved in C++ using virtual functions. If a function with same name exists in base as well as parent class, then the pointer to the base class would call the functions associated only with the base class. However, if the function is made virtual and the base pointer is initialized with the address of the derived class, then the function in the child class would be called.