Revised Definition – Relational Database

Posted on February 16, 2023 by

Corbyn Kwan Posted in Write or Flight — No Comments ↓

Introduction

This assignment’s objective is the following:

Appreciate the importance and role of definitions in technical writing
Understand how audience and purpose indicate the need for definition
Differentiate between the levels of details in definition
Select the right level of detail according to the situation

To do this, we define a complex term within our discipline or profession to a non-technical audience in the following ways:

Parenthetical definition
Sentence definition
Expanded definition

Situation and Audience

A software engineer explains to their manager how their customer’s data is stored in a computer.

Parenthetical definition

Relational databases (databases where data is stored in rows and columns) are a common type of database to organize and store data.

Sentence definition

Relational databases are a type of database built upon a relational model. This database is characterized by its relational database management system, and Structured Query Language (programming language used to communicate to the database) for reading and writing data from the database.

Expanded Definition

History of relational databases

The most common database type in the 1960s were hierarchical databases where data is organized in a family tree type structure, where for example an Animal contains a Mammal which contains a Dog which contains a Golden Retriever.

Most data don’t have a hierarchical structure so E.F. Codd developed relational databases in 1970 where data is stored in relations, and if a common attribute can be used to link relations of a relation structure exists.

How do relational databases work?

Relation name: Customers

CustomerID	Name
1	John
2	Sarah

Figure 1: Example of a relation

We can imagine relational databases as a collection of spreadsheet files. Using spreadsheets as an analogy, relation databases contain the following:

table (relation)
rows (tuples)
columns (attributes).

Referring to Figure 1, imagine we have a spreadsheet file “Customers”, in this case, the relation is called <Customers>, a tuple is <CustomerID: 1, Name: John>, and attributes are <CustomerID, Name>.

How does Structured Query Language work?

Structured Query Language was made by IBM in the early 1970s. It’s the main language that programmers use to query (fetch data) from relational databases. It’s formatted the following way:

SELECT <attribute(s)>

FROM <relation>

WHERE <condition>

Referring to Figure 1, an example of a query fetching all the customers with the name “John” would be:

SELECT *

FROM Customers

WHERE Name == "John"

To conclude, relational databases seem complex but fundamentally, it’s spreadsheets. Feel free to contact me for any inquiries.

References

Burleson, D. (n.d.). The Hierarchical Database Model. Retrieved February 8, 2023, from http://www.dba-oracle.com/t_object_hierarchical_database.htm

Codd, E. F. (1970). “A Relational Model of Data for Large Shared Data Banks”. Communications of the ACM. 13 (6): 377–387.

Chamberlin, Donald. (2012). “Early History of SQL”. IEEE Annals of the History of Computing. 34 (4): 78–82.

Note: Created my own image for the 3rd reference (The Figure). According to APA rules, no citation is needed.