You should be able to…(NOTE: Highlighted in red is KEY information that you should learn)

  • Understand the relationship between entities and tables

-An entity is a type of real world object (about which data is to be stored) • e.g. songs/albums/singers etc 

-In the relational database each entity is modelled as a table. Basically, an entity becomes a table in a relational database

-Instances of an entity are represented by records/rows of the table

-Entities can have attributes  e.g. length of song

-Attributes of an entity are represented by fields/columns of the table

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  • Understand the components of a relational database, such as tables, forms, queries, reports and modules (LINK)
  • Understand the use of logical operators in framing database queries

LOGICAL OPERATORS = AND, OR, NOT. These are used to structure queries (searches) and extract data from a database.

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For example, if we wanted to search the database above for all of the people who live in ‘San Francisco’ and spent more than $500, we would do the following;

City = “San Francisco” AND Amount spent > 500

Now imagine we wanted to search (query) for all of the people who live in ‘San Diego’ or spent less than $300, we would do the following;

City = “San Diego” OR Amount spent < 300

  • Explain the use of key fields to connect tables and avoid data redundancy

Key Fields are used in a Database to ‘uniquely identify each record’. These are also used to create relationships between tables. So, a key field in one table can become a ‘foreign key’ in another table. This helps to reduce data redundancy (The unnecessary repetition of data). 

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  • Describe methods of validating data as it is input
Validation “The process of checking data as it is input to ensure that it is reasonable”

Types of Validation check are as follows;

-Range Check

-Type Check

-Length Check

-Presence Check

TOPIC OVERVIEW (Test your Knowledge)

Useful Links

BBC Bitesize

Relational Database Tutorial

Have a go at these tutorials to get practical experience of setting up your own relational database. This will help with your understanding of the theory content that you are required to know.

Class Discussion/ Interactive Task