
A special case of a derivable attribute is where an attribute type is redundantly
duplicated, as in:
Employee (employeeNo, employeeName, projectNo, projectName)
Project (projectNo, projectName, projectStartDate)
Here, projectName is immediately available within either table.
Questions
1. An entity table is defined as:
Machine (machineNo, type, location, contractorAddress, contractType,
contractServiceDate, contractCharge)
Maintenance contracts apply to only 10 per cent of machines. Suggest how the table
could be flexed into two tables to reduce storage requirements. (1 min)
2. With reference to question 1, both the tables generated by flexing would have to ...