Validation of Type-D and Schengen visas ?

My name is RAM , I'm a civil engineer  from INDIA . I want to immigrate under green card scheme .
I want to know  ,
1. what is Type-D , its validation ,to whom they give it ?
2.what is Schengen visa , its validation , who are eligible for it ?

Type D is a long-term Schengen visa.

http://www.schengenvisainfo.com/schengen-visa-types/http://www.nyidanmark.dk/en-us/coming_t … w_long.htm

A Type D visa is an entry permit generally issued to enable applicants who have been granted residence permit e.g. greencard to travel to Denmark. The D-visa is territorially restricted to Denmark--it allows the applicant to transit through other Schengen airports, but it does not allow the holder of the visa to travel into other Schengen countries.

A Schengen Visa, on the other hand, is a short-term visa that allows a foreign national to visit Denmark as well as other countries in the Schengen Area for a maximum of 90 days within a 180-day period.