Lesson Notes By Weeks and Term v5 - Grade 11

Lesson Video

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Performance objectives

• Apply fundamental database design principles like normalization and ERDs.
• Construct SQL queries to manipulate data (SELECT, INSERT, UPDATE, DELETE).
• Demonstrate proficiency in procedural programming concepts.
• Evaluate different data representation methods.
• Analyze the impact of ICTs on South African society.

Lesson summary

This week's focus is on integrated revision and exam preparation, specifically targeting the core concepts covered in the first term. Exam preparation isn't just about memorizing facts; it's about understanding the underlying principles, applying your knowledge to solve problems, and feeling confident in your abilities. In South Africa, having strong IT skills is increasingly important for accessing opportunities in various sectors, from small businesses needing websites to large corporations managing complex systems. Mastering these concepts will equip you to participate more effectively in the digital economy and contribute to South Africa's technological advancement.

Lesson notes

This week, we will reinforce core concepts from Term 1, focusing on Databases, SQL, Procedural Programming, Data Representation, and ICT's impact on society.

A. Databases and SQL: What is a Database? A database is an organized collection of structured information, or data, typically stored electronically in a computer system. Databases are crucial for managing large amounts of data efficiently. They enable quick searching, sorting, and updating of information. Imagine a school managing student records – a database allows them to easily find student information, track attendance, and manage grades.

Relational Databases: Relational databases organize data into tables with rows (records) and columns (fields). Each table represents an entity (e.g., Student, Teacher, Course). Relationships between tables are established using primary and foreign keys.

Normalization: Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. Common normal forms include 1NF, 2NF, and 3N

F. Redundancy leads to inconsistencies and difficulties in updating data. 1NF (First Normal Form): Eliminate repeating groups of data. Each column should contain only atomic values (indivisible). 2NF (Second Normal Form): Be in 1NF and eliminate redundant data that depends on only part of the primary key. This applies when the primary key is composite (made up of more than one attribute). 3NF (Third Normal Form): Be in 2NF and eliminate redundant data that depends on another non-key attribute (transitive dependency).

Entity-Relationship Diagrams (ERDs): ERDs are visual representations of database structures, showing entities (tables), attributes (columns), and relationships between entities. They are essential for planning and designing databases.

SQL (Structured Query Language): SQL is the standard language for interacting with relational databases. It allows you to retrieve, insert, update, and delete data.

SELECT: Retrieves data from the database. `SELECT column1, column2 FROM table_name WHERE condition;` INSERT: Adds new data into the database. `INSERT INTO table_name (column1, column2) VALUES (value1, value2);` UPDATE: Modifies existing data in the database. `UPDATE table_name SET column1 = value1 WHERE condition;` DELETE: Removes data from the database. `DELETE FROM table_name WHERE condition;` Example (Normalization): Let's consider a table storing information about students and their courses: | StudentID | StudentName | CourseID | CourseName | Instructor | InstructorOffice | |---|---|---|---|---|---| | 1 | Aisha | 101 | Maths | Mr. Smith | Room 201 | | 1 | Aisha | 102 | Science | Ms. Jones | Room 202 | | 2 | Bongani | 101 | Maths | Mr. Smith | Room 201 | This table is not in 3NF because `InstructorOffice` depends on `Instructor`, which is not part of the primary key (StudentID, CourseID). To normalize this, we create two tables: StudentCourse Table: | StudentID | StudentName | CourseID | |---|---|---| | 1 | Aisha | 101 | | 1 | Aisha | 102 | | 2 | Bongani | 101 | CourseInstructor Table: | CourseID | CourseName | Instructor | InstructorOffice | |---|---|---|---| | 101 | Maths | Mr. Smith | Room 201 | | 102 | Science | Ms. Jones | Room 202 | Now, the data is normalized, reducing redundancy and improving data integrity.

B. Procedural Programming: What is Procedural Programming? Procedural programming is a programming paradigm where programs are structured into a sequence of procedures (also called functions or subroutines). Programs execute instructions sequentially, following a top-down approach.

Key Concepts: Variables: Storage locations in memory that hold data.

Data Types: Specify the type of data a variable can hold (e.g., integer, string, boolean).

Control Structures: Control the flow of execution. if/else: Executes different code blocks based on a condition. for/while loops: Repeats a block of code multiple times.

Functions: Reusable blocks of code that perform specific tasks.

Example (Python): ```python def calculate_discount(price, discount_percentage): """Calculates the discounted price.

Args: price: The original price of the item. discount_percentage: The discount percentage (e.g., 10 for 10%).

Returns: The discounted price. """ discount_amount = price * (discount_percentage / 100) discounted_price = price - discount_amount return discounted_price original_price = 200 discount = 15 final_price = calculate_discount(original_price, discount) print(f"The discounted price is: R{final_price}") #using f-string ``` This Python code defines a function `calculate_discount` that calculates the discounted price of an item. It demonstrates the use of variables, data types (integer, float), and a function. The `f-string` is used for formatted output.

C. Data Representation: Binary: The base-2 number system, using only 0 and

1. It is the fundamental language of computers.

Decimal: The base-10 number system, which we use in everyday life.