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Gatcombe 1
E.F. Codd: Inventor of the Relational Database (pg 10.31)
Data
Data us a collection of unprocessed items,
which can include text, numbers, images, audio
and video.
Database
A database is a collection of data organized in a
manner that allows access, retrieval and use of
that data.
Relational Database
A relational database is a database that stores
data in tables that consists of rows and columns
Query Language
A query language consists of simple, Englishlike statements that allow users to specify the
data to display, print or store.
The relational database, which organizes data into simple rows and columns, was
invented by the IBM Mathematician, Edgar F. Codd. Codd, who received his PhD from the
University of Michigan, has created basic criteria for the composition of databases. His studies
began at Oxford University with a full scholarship, majoring in Mathematics and Chemistry. He
became a pilot during WWII and shortly after moved to New York looking for work. In 1949 he
was hired as a researcher by IBM where he began producing a number of computer-based
products at their San Jose Research Laboratory. But it was Codd’s unique research paper “A
Relational Mode of Data for Large Shared Data Banks” (written in 1970), that revolutionized the
way we look at informational management today. At first Codd’s new idea was not well accepted
in the technical community; his theory seemed too radical. Finally, in 1978 Frank T. Cary, the
executive director of IBM, ordered his company to create a product with Codd’s design. It was
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Gatcombe 2
from here that the popular demand for relational databases began. Today these databases are used
on a variety of systems, ranging from hospitals' patient records to airline flights and schedules.
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Codd’s paper proposed his new revolutionary theory of relational database’s by
highlighting twelve principles or rules of importance. Rule 1 states that all information must be
presented in the form of a table. Rule 2 implies that all data should be easy to read and
understand without any vagueness. Rule 3 states that a field should be accepted to be
blank, without the value of zero. Rule 4 says that similar tools must be used to access data on
a system as well as to its structural components. Rule 5 expresses that each database must
contain one, clearly understood and defined language, also known as Structured Query
Language. Rule 6 states that information should be presented in a “view”, in which data
can be presented to the person in different logical combinations. Rule 7 says that data can
be retrieved from any table or row in a database available. Rule 8 tells the user that they
are unable to undergo the physical attempt to retrieve or store data. Rule 9 expresses that
data should be understood in the same way, even when changing the structure (such as a
table). Rule 10 tells that a database should have consistent structured query language.
Rule 11 states that a user should have no knowledge of the distribution of a database.
Finally, rule 12 implies that data structure can only be manipulated with an administrative
tool that performs multiple row standard database language (like SQL). All these
principles were based on one most imperative point, Rule Zero, which “mandates that any system
identified as a relational database management system must be able to manage databases entirely
through its relational capabilities” (Vermaat 10.31).
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Edgar Frank Codd’s 12 Principles for a Relational Database

The Information Rule

Guaranteed Access Rule

Systematic Treatment of Null Values

Dynamic On-Line Catalog Based on the Relational Model

Comprehensive Data Sublanguage Rule

View Updating Rule

High-level Insert, Update, and Delete

Physical Data Independence

Logical Data Independence

Integrity Independence

Distribution Independence

Non-subversion Rule
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In 1981 Codd received the most prestigious ACM A.M. Turing Award from the
Association of Computing Machinery, based on his lifetime of technical work and contributions
to the community. Adding to this success, Codd developed a paper which defined online
analytical processing, also known as OLAP. With this document came the expansion and success
of the OLAP market. Edgar Frank Codd died in August of 2003 but his inventions and
revolutionary research papers will continue to lead the world in organized technical information
and management support.
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Bibliography
“Codd's 12 Rules: Data Management Strategies”. Itworld.com
7 May 2001. <http://www.itworld.com/nl/db_mgr/05072001/>
Hafner, Katie. “Edgar Codd, database theorist, dies at 79”. New York Times
23 April 2003. < http://news.com.com/2100-1012-997975.html>
Vermaat, Shelly C. Discovering Computers 2004: A Gateway to Information.
Boston: Course Technology, 2003. 10.31.
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