Database Systems: Concepts, Design and Applications

9.3. Decomposition

A functional decomposition is the process of breaking down the functions of an organisation into progressively greater (finer and finer) levels of detail. In decomposition, one function is described in greater detail by a set of other supporting functions. In other words, decomposition is done to break the modules in smallest one to convert the data models in normal forms to avoid redundancies. The decomposition of a relation scheme R consists of replacing the relation schema by two or more relation schemas that each contain a subset of the attributes of R and together include all attributes in R. The algorithm of relational database design starts from a single universal relation schema R = {A₁, A₂, A₃,....., A_n}, which includes ...