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
- 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.
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).
- 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;
TOPIC OVERVIEW (Test your Knowledge)
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.