a database program let's you create an index - a list of records ordered according to the content of certain fields. this helps you to search the database and sort records into numerical or alphabetical order very quickly. Modern databases are relations - that is, they are made up of related files.;customer and orders, vendors and purchases,students and tutors, etc. Two database files can be related as long as they have a common field called Tutor I'd and another file with details ot the tutors could include the same field. This key field can be used to relate the two files. Database link Oracle, DB2 and Mysql 9an manage these relationships.