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Relational Databases
A database is an organized collection of data
Some commercial products:
MS Access, MS SQL Server, DB2, Oracle, mySQL, Sybase,
db4o, Versant, IMS, Total, …
Relational Databases introduced by E. F. Codd in 1969
A relational database is a collection of relations
Relations
 A relational database comprises relations
 Common name for relation is table
 Structure: a table is a collection of rows and columns
 Structure resembles appearance of some spreadsheets
 everybody is familiar with tables
 this simplicity is one reason why relational databases have
been very successful
o in contrast IMS, Total, Versant are not so simple
Small Example: database of one relation
Employees
Employee Id First
Last
Name
Name
123
Joe
Smith
333
Jim
Jones
456
April
Smith
842
Jenny
Jones
777
Tom
Lee
Gender
Male
Male
Female
Female
Male
Verbalization
We must be able to verbalize the information in a table.
For the above
Employee with ID … has a first name …, a last name …,
and is of … gender
Employee with ID 123 has a first name Joe, a last
name Smith, and is of Male gender
Employee with ID 333 has a first name Jim, a last
name Jones, and is of Male gender
Microsoft Access
 MS Access is a relational database system for workstations
that run the Microsoft Windows operating system.
 typically used by individuals for data they use personally
 in some situations a single MS Access database may be
used by a group of people or small department.
 MS Access databases are stored in a single file that has a
file suffix of “.accdb” or “.mdb”.
 Databases created using MS Access 2007 and later have a
file suffix “.accdb”, and databases created using MS Access
2003 or earlier have a file suffix “.mdb”.
 We will be using databases where the files have names
ending in “.accdb”. You need to use MS Access 2007 or
later to open the sample databases.
MS Access Example:
 Library.accdb
 3 tables: Member, Book, Loan
 Datasheet View vs Design View
 Viewing data
 Modifying/adding/deleting data