What is data independence?

Data Independence: Techniques which permit data to be changed without affecting the applications in which procedure it. There are two types of data independence. The first type is data independence for data that is accomplished in a database management system (DBMS). It permits the database to be structurally changed without affecting most existing programs. Programs access data in a DBMS through field and are concerned with just the data fields they use, not the format of the finished record. Therefore, when the record layout is updated (fields added, deleted or changed in size), the only programs which must be changed are those in which use those new fields.