Germany Jahrgangsstufe 9 Computer Science

Chapters: 4

1. Functions, data flow and spreadsheets

Spreadsheets, functions and data flow

Spreadsheets in Accounting: Formulas, BRS, Schedules, Ratios and Charts – A spreadsheet is a grid of rows and columns where each cell can hold a number, a word or a formula. When one number changes, every formula that uses it updates by itself. Accountants use spreadsheets for bank reconciliation, depreciation and loan schedules, payroll, ratio analysis and charts.

Data modelling and relational databases

SQL with MySQL: Create Tables, Change Rows and Ask Questions – SQL (Structured Query Language) is the language used to talk to a relational DBMS like MySQL. DDL commands (CREATE, ALTER, DROP) define tables; DML commands (INSERT, UPDATE, DELETE) change rows; DQL (SELECT) reads data. Each column has a data type such as INT, FLOAT, CHAR, VARCHAR or DATE. SELECT … WHERE filters rows using relational operators, BETWEEN, AND/OR/NOT and IS NULL.

Object-oriented modelling and programming

Object-Oriented Programming (OOP) – Object-oriented programming builds a program out of objects. A class is a blueprint that lists the data (attributes) and actions (methods) its objects will have. Each object is made from a class and keeps its own data. The four big ideas are encapsulation (hide data behind methods), inheritance (a new class reuses an old one), polymorphism (the same method call behaves in the right way for each object) and abstraction (show only what is needed).

Data protection and privacy

Data Privacy: Who Gets Your Data and How to Protect It – Personal data is any information that can point to you. Apps and websites collect it all the time. Privacy means you control who sees it and how it is used. Fair rules say data must be used for a clear purpose, kept small, kept safe and deleted when done. You have rights over your data, and simple habits keep you safe.