Database Primary Key: A primary key is a combination of one or more column values in a table that make a row of data unique within a database table. Identification of primary keys is an important part of entity type identification. Ideally, primary keys should be. stable and.
It depends on their experience, the industry of their clients, what their special â¦ ty is, their location, etc., etc.According to the U.S. Department of Labor, the 2002 median annual earnings of salaried computer programmers was $60,290.
The Bureau of Labor Statistics estimated an average salary for computer hardware engineers of $101,360 per year in 2011. Systems and applications software engineers and developers earned an average salary of $89,280 per year in 2011, according to O*NET.