Theory question 101
Database ManagementPaper 2, Section A: Essay
(a)(i) What is data model? (ii) State three types of data model. (b)(i) List three approaches to data modelling. (ii) Explain any one approach listed in 1(b)(i).
Show the model answer
(a)(i) A data model is a plan (representation) showing how data is organised, how data items relate to each other and how they are stored and processed in a database.
(ii) Any three: conceptual; logical; physical data model (or hierarchical, network, relational, object-oriented models).
(b)(i) Any three: hierarchical; network; relational; object-oriented; entity-relationship approach.
(ii) e.g. Relational: data is kept in tables (relations) of rows and columns, and tables are linked by keys. Or Hierarchical: records are arranged in a tree of parent and child records, each child having one parent. Or Object-oriented: data and the operations on it are stored together as objects with attributes and methods.
Explain one approach well, with how data is arranged in it.