Database Concepts – JSS3 Digital Technologies Lesson Note (First Term)

A database is an organised collection of related information, stored so that it can be found, updated and used quickly.

Behavioural objectives

By the end of the lesson, students should be able to:

1. Define a database and give its simple meaning.
2. State at least four reasons why databases are important.
3. Give examples of databases used in daily life.
4. Identify a table, a field and a record in a given table.
5. State what a primary key and a database management system are.

What is a database?

A database is a collection of related information that is organised so that it can be easily managed and accessed.

• School bag example: if pens, biscuits, notebooks and old assignments are thrown in without order, finding a ruler takes a long time.
• Database idea: a database keeps information in order, like a tidy bag, so any item is found quickly.
• Manual database: a stack of paper folders in metal cabinets. Finding a student’s record from 1995 could take hours.
• Electronic database: information stored on a computer or in “the cloud”. One name out of a million can be found in less than a second.

What is the difference between a manual and an electronic database?

• Manual database: information kept on paper, in files and cabinets, and searched by hand.
• Electronic database: information kept on a computer and searched with software.

Why do we need databases?

We need databases because a simple list becomes messy and slow to use when the information grows big.

1. They save space: a tiny memory card can hold more information than a room full of paper files.
2. They are fast: searching a printed dictionary for a word takes longer than a search on a computer or phone.
3. They keep information accurate: rules can be set. A “Date of Birth” field will not accept the word “Banana”.
4. They give security: a database can be locked with a password, but a sheet of paper on a desk cannot.
5. They allow sharing: many people can view the same database at the same time, even from different cities.

Where do we see databases in daily life?

We use databases every day, even if we have never opened a database program such as Microsoft Access.

• Phone contacts: stores names, phone numbers and emails. Searching for “Mum” is a query, which means a request to search the database.
• School records: hold your name, house, grades and your parent’s phone number.
• Banking: an ATM checks a database to confirm there is enough money in the account before it gives out cash.
• Social media: Facebook, Instagram and TikTok use huge databases to store photos, comments and “likes”.
• Library: tracks which books are on the shelf and which student has borrowed them.

What are the parts of a database?

The three basic building blocks of a database are the table, the field and the record.

Table

• Table: the whole grid of information, such as a “Students” table.

Field

• Field: one category of information, shown as a column.
• Examples: “First Name” is a field. “Phone Number” is another field.

Record

• Record: all the information about one person or item, shown as a row.
• Example: Row 5 holds everything about John Doe: his age, class and address. That whole row is his record.

Example of a Students table

• Fields: Student ID, First Name, Class and Phone Number (the four columns).
• Records: the three rows, one for each student.

What is a primary key?

A primary key is a field whose value is different for every record, so it identifies each record exactly.

• Example: Student ID. Two students may share a first name, but never an ID.
• Rule: a primary key must not be empty and must not repeat.

What are the common data types of a field?

A data type tells the database what kind of entry a field will accept.

• Text: letters and mixed characters, such as names and addresses.
• Number: figures used for counting or calculating, such as age or marks.
• Date/Time: dates and times, such as date of birth.
• Currency: money values, such as school fees.
• Yes/No: only one of two answers, such as “Fees paid”.

What is a database management system?

A database management system (DBMS) is software used to create, store, change and search a database.

• Microsoft Access: a DBMS often used in schools.
• LibreOffice Base: a free DBMS.
• MySQL: a DBMS used for websites and larger systems.

Class activity: the “Human Database”

This activity lets students build a small table on the chalkboard.

1. Pick five students.
2. Draw a table on the chalkboard with three fields: Name, Favourite Colour and Best Subject.
3. Fill in one row for each of the five students.
4. Ask students to point out a record (one student’s full information).
5. Ask students to point out a field (for example, the list of all favourite colours).

Evaluation

1. Define a database in one sentence.
2. State four reasons why an electronic database is better than a paper list.
3. Name three databases you use or meet in daily life.
4. In a table, what is the difference between a field and a record?
5. What is a primary key? Give one example.

Assignment

Draw a table for a “Class Library” database with at least four fields and five records. Label one field, one record and the primary key.