1. Define the term database.
2. What is an attribute? How is it related to an entity?
3. What is data redundancy? Why is it a problem?
4. How would you describe the traditional approach to data management? How does it differ from the data base approach?
- An organised storage of logically related records could describe a database. This integrated collection of data is independent of application programs using the data.
- A data field represents an attribute [a characteristic or quality] of some entity [object, person, place, etc]. For example, an employee’s salary is an attribute that is a typical data field used to describe an entity who is an employee of a business. Thus an attribute is an identifiable part of the whole, that is the record.
- In a traditional approach to data management, data redundancy is among many of the problems. For example, a school will have student data in an enrolment fees file, in a class roll file, and a grades assessment file; all independently reproducing the same data. This repeated information is both a waste of storage space; and leads to inconsistent data, with no way of knowing which is correct.
- The traditional approach is not integrated. Every department of information has its own independent file, which often duplicates some of the data stored in other departments. The database approach integrates and rationalises the data into a centralised storage system. Data redundancy, data isolation (difficulty accessing data from different applications) and data inconsistency are minimised in a database approach. Additionally, data updates are easier because the data is stored in one accessible location. The drawbacks of a database management system (DBMS) include the cost of purchase and operation environment as well as any specialist staff required. If security is breached, more data is accessible to a trespasser. Also a failure in the DBMS will affect all application programs depending on it.