ECE356 Lecture Notes - Lecture 10: Mcgraw-Hill Education, Computer Engineering, First Normal Form

• School: University of Waterloo
• Department: Electrical and Computer Engineering
• Course: ECE356
• Professor: Zarnett

Document Summary

So far, we learned the syntax to create tables, and how to turn modelling diagrams into tables and all the various bits and pieces about how modelling diagrams work. The modelling diagrams give us some guidance and tell us about wrong ways to represent the data, but we don"t yet have enough guidance as to what is correct. If we do a good job the relation will be in a normal form. Intuition might tell you no, but think about why. In the combined relation, if there are two instructors, say, sedra and smith, both members of department of electrical & computer engineering, in both tuples there will be an entry for the budget of the department. The budget data is duplicated and risks becoming inconsistent. Our intuition may tell us this is bad, but we would like a way to express it formally. Informally the rule is that each value of department name corresponds to at most one budget.