Coding and Technology Module 1 Lesson 4 Summary Notes PDF

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Professional Diploma in Introduction to Technology

Databases Lesson 4: Summary Notes

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Contents 3

Lesson outcomes Data

5

Relational databases

7

Database management

8

References

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Lesson outcomes In this lesson you will learn about data versus information, processing data, organising data and data as a commodity, you will also learn about relational databases, the structure of a database, entity relationship diagrams and identifying relationships. This lesson also covers database management, defining what it is and the role of a database administrator, tools for managing databases and database programming languages (SQL).

Data Data

Information

Data refers to raw facts

The result after data has been processed

Data are the foundation of information

Requires context to reveal meaning

Organisations use data as part of making strategic decisions

Accurate, relevant, timely information is key

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Data processing •

Data processing is the conversion of raw data to meaningful information

•

Use of computer systems and software to carry out a number of operations on the data

(Medium, 2017) Organising and storing data Life-cycle of processing data: 1. Collection 2. Preparation 3. Input 4. Processing 5. Output 6. Storage Data as a commodity As of recent, data has officially become more valuable than oil. This means that data is now more valuable than what used to be the world’s most valuable commodity. (Technative, 2019)

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Relational databases

Structure of a relational database A relational database is one that is highly useful to organise data into collections of two-dimensional tables called relations. (Chesney, Stair and Reynolds, 2017) Characteristics of a relational database A typical relational database consists of multiple related tables, also known as entities, which comprise of multiple records and fields. •

Entity/Table

•

Record

•

Field

•

Primary Keys

•

Foreign Keys

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Entity Relationship Diagram (ERD) An Entity Relationship Diagram (ERD) is a snapshot of data structures. An Entity Relationship Diagram shows entities (tables) in a database and relationships between tables within that database.

(Source: Bizzdesign) Identifying relationships When designing a relational database, the best way to resolve relationships between entities is by creating a logical set of business rules. •

One-to-one

•

One-to-many

•

Many-to-many

•

Optional

(Source: Chesney, Stair and Reynolds, 2017)

(Source: Symmetric)

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Database management Database Administrator (DBA) •

Work with users to define their data needs

•

Identifies entities of interest

•

Applies database programming languages

•

Tests and evaluates databases

•

Implements changes

•

Ensures data is secure from unauthorised access

Relational database management system A database management system is a collection of programmes used to manage the structure and control access to data. Here are some considerations when designing and building a database system: •

Content

•

Access

•

Physical organisation

•

Logical structure

Types of database management systems •

Single-user

•

Multi-user

•

Flat files

Tools for managing databases •

MySQL

•

Oracle XE

•

MS SQL Server

SQL database programming Structured Query Language (SQL) is a special-purpose programming language for accessing and manipulating data stored in a relational database. SQL allows us to: •

Select data

•

Project data

•

Join tables

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References •

Bizzdesign (no date) Modeling with ERD - Support - BiZZdesign Support. Available at: https://support.bizzdesign.com/ display/knowledge/Modeling+with+ERD

•

Chesney, T., Stair, R. M. and Reynolds, G. W. (2017) Principles of Business Information Systems. Cengage Learning. Available at: https://books.google.co.za/books?id=gow8swEACAAJ.

•

Medium (2017) The 6 Stages of Data Processing Cycle | by PeerXP Team | Medium. Available at: https://medium.com/@ peerxp/the-6-stages-of-data-processing-cycle-3c2927c466ff

•

Symmetric (no date) ERD Notation – Symmetric GmbH. Available at: https://www.symmetric.ch/wiki/sql-wiki-2/erdnotation/?lang=en

•

Technative (2019) Data – the World’s New Precious Commodity – TechNative. Available at: https://www.technative.io/ data-the-worlds-new-precious-commodity/

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