ECE356 Lecture Notes - Lecture 9: Level Set, Foreign Key, Mcgraw-Hill Education

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

Document Summary

Lecture 9 reduction to relational schema, design decisions. If we have an entity-relation diagram, eventually we will want to turn that into a set of database tables. The conversion routine is not especially complicated and after a small amount of practice it is likely that you will be able to do it quickly and e ciently. Strong entities are the easiest to turn into tables. The name of the table will be the name of the entity (surprise) and the attributes in the diagram become the attributes in the relation. The primary key in the table will be the same as the primary key in the diagram. If the diagram says an instructor has (id, name, salary) and id is the primary key, then the create table statement will assign types and lengths to these elds. Suppose a is a weak entity set and the strong attribute it depends on is b.