Relational Database

What's a Database?

	1. a system for storing and managing information
	2. a collection of relations

What's a Relation?

	1. a table in a database
	2. a set of tuples (no duplicates)

What's a Tuple?

	1. a row in a relation
	2. an ordered list of values

What's an Attribute?

	1. the name of a column in a relation
	2. the name of a position in a tuple

What's a Scheme?

	the set of column names of a relation


















Example Database

Why is the data split into multiple tables?
How are the tables connected?
(How can I find courses and grades for "C. Brown"?)

StudentID  Name		Address		Phone
12345	   C. Brown	12 Apple St.	555-1234
67890	   L. Van Pelt	34 Pear Ave.	555-5678
22222	   P. Patty	56 Grape Blvd.	555-9999

Course	StudentID  Grade
CS101	12345	   A
CS101	67890	   B
EE200	12345	   C
EE200	22222	   B+
CS101	33333	   A-
PH100	67890	   C+

Course	Prerequisite
CS101	CS100
EE200	EE005
EE200	CS100
CS120	CS101
CS121	CS120
CS205	CS101
CS206	CS121
CS206	CS205

Course	Day  Hour
CS101	M    9AM
CS101	W    9AM
CS101	F    9AM
EE200	Tu   10AM
EE200	W    1PM
EE200	Th   10AM
PH100	Tu   11AM

Course	Room
CS101	Turing Aud.
EE200	25 Ohm Hall
PH100	Newton Lab.