NIELIT A Level
Introduction to Database Management System
Consider the following requirements for a construction company that uses database system to keep track of its projects, workers and material requirements of various projects.
The projects for the company are of two kinds: (i) Turn key projects and (ii) Others.All the projects have a life cycle (Please note that the turn key projects have a maintenance phase in addition.) and workers are allotted as per the phase of the project. Each project has its own plan of completion that is drawn at the start of the project. The worker and material requirement of project is calculated at the start of the project.
The store manages the materials. One of the major constraints for the store is that it requires 15 days to acquire a product. Thus, the inventory should fulfil the requirements of
the next 15 days.
The store also keeps track of the issue of materials and return of defective materials to various projects.
The company keeps the information of all the clients including the information about the projects that are being maintained by the company (turn key projects).
Draw an ER diagram for the above company. Specify key attributes and constraints of each entity type and of each relationship type. Note any unspecified requirements and make appropriate assumptions to make the specification complete. Also, design the normalised
tables with required integrity and security constraints.