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Responding to change (a2 only)
Infection and response
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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
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Genetic information & variation
Inheritance, variation and evolution
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1l the quest for political stability: germany, 1871-1991
Britain & the wider world: 1745 -1901
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
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Computer Science
27 Nov 2025
129
5 pages
ignatius @icarusfellover
A comprehensive guide to database design and SQL implementation focusing on entity-relationship diagram design best practicesand query... Show more
This section explores the detailed aspects of entity relationships and data organization through entity occurrence diagrams and data dictionaries.
Definition Entity occurrence diagrams illustrate specific instances of relationships between database entries.
Vocabulary A data dictionary provides comprehensive information about database structure including tables, attributes, and validation rules.
Highlight Primary keys uniquely identify records while foreign keys establish links between tables.
Example A compound key combines multiple attributes that are primary keys from different tables, connected with a '+' symbol.
Implementation phase covers SQL operations with particular focus on wildcards and aggregate functions for data manipulation.
Definition Wildcards are special characters used to substitute for other characters in string operations.
Example The '%' symbol represents zero or more characters while '_' represents exactly one character in SQL LIKE operations.
Highlight Aggregate functions like AVG(), COUNT(), MAX(), MIN(), and SUM() operate on sets of rows to return statistical values.
Quote "Mixing non-aggregate and aggregate expressions in a SELECT statement is not permitted without proper GROUP BY clause"
This section details advanced SQL concepts including aliases, grouping operations, and update statements.
Definition Aliases provide temporary names to columns in result tables using the AS keyword.
Example "SELECT product_name AS FROM Product"
Highlight GROUP BY clauses enable combination of aggregate and non-aggregate expressions for grouped columns.
Vocabulary Nested queries allow the results of one query to be used within another query.
The final phase focuses on validating SQL code functionality and assessing its fitness for purpose.
Definition Testing involves comparing expected outputs with actual results to verify code functionality.
Highlight Evaluation must consider both functional requirements and end-user needs.
Example Testing documentation should include expected output details and actual output screenshots.
The initial phase of database development focuses on identifying user requirements and designing appropriate database structures. Entity-relationship diagrams serve as the foundation for database architecture.
Definition Entity-relationship diagrams are graphical representations showing the relationships between different entities in a database system.
Vocabulary Cardinality refers to the numerical relationship between entities .
Example A Resort-Customer booking system demonstrates relationships between entities like Hotel, Resort, and Booking tables.
Highlight Many-to-many relationships must be broken down into two one-to-many relationships for implementation in relational databases.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Master key SQL commands with this concise cheat sheet covering SELECT, INSERT, UPDATE, DELETE, and JOIN statements. Perfect for GCSE and National 5 revision, this resource provides clear examples and syntax to enhance your database query skills.
Computer ScienceExplore the fundamental concepts of Object-Oriented Programming (OOP) with this comprehensive guide. Covering key topics such as classes, objects, inheritance, encapsulation, polymorphism, and class diagrams, this resource is designed for AQA A-Level Computer Science students. Understand the principles of OOP and how to effectively apply them in programming.
Computer ScienceExplore essential Python programming constructs including variables, control structures, operators, and data types. This summary covers key definitions such as strings, arrays, and the differences between local and global variables, providing a solid foundation for understanding Python basics.
Computer ScienceExplore essential programming techniques including recursion, iteration, and modular programming. This summary covers key concepts such as algorithms, debugging, and data abstraction, providing a clear understanding of problem-solving methods in computer science. Ideal for OCR A-Level Computer Science students.
Computer ScienceExplore essential programming constructs including loops, conditionals, and object-oriented principles. This summary covers key concepts such as recursion, encapsulation, inheritance, and the differences between local and global variables. Ideal for OCR A Level Computer Science students preparing for Component 2.2.
Computer ScienceExplore key concepts of pseudocode including assignment statements, conditional statements, loops, and object-oriented programming. This summary covers essential programming constructs such as arrays, inheritance, and string handling, providing a comprehensive overview for students learning to write pseudocode effectively.
Computer ScienceApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
ignatius
@icarusfellover
A comprehensive guide to database design and SQL implementation focusing on entity-relationship diagram design best practices and query optimization.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section explores the detailed aspects of entity relationships and data organization through entity occurrence diagrams and data dictionaries.
Definition: Entity occurrence diagrams illustrate specific instances of relationships between database entries.
Vocabulary: A data dictionary provides comprehensive information about database structure including tables, attributes, and validation rules.
Highlight: Primary keys uniquely identify records while foreign keys establish links between tables.
Example: A compound key combines multiple attributes that are primary keys from different tables, connected with a '+' symbol.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Implementation phase covers SQL operations with particular focus on wildcards and aggregate functions for data manipulation.
Definition: Wildcards are special characters used to substitute for other characters in string operations.
Example: The '%' symbol represents zero or more characters while '_' represents exactly one character in SQL LIKE operations.
Highlight: Aggregate functions like AVG(), COUNT(), MAX(), MIN(), and SUM() operate on sets of rows to return statistical values.
Quote: "Mixing non-aggregate and aggregate expressions in a SELECT statement is not permitted without proper GROUP BY clause"
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section details advanced SQL concepts including aliases, grouping operations, and update statements.
Definition: Aliases provide temporary names to columns in result tables using the AS keyword.
Example: "SELECT product_name AS FROM Product"
Highlight: GROUP BY clauses enable combination of aggregate and non-aggregate expressions for grouped columns.
Vocabulary: Nested queries allow the results of one query to be used within another query.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The final phase focuses on validating SQL code functionality and assessing its fitness for purpose.
Definition: Testing involves comparing expected outputs with actual results to verify code functionality.
Highlight: Evaluation must consider both functional requirements and end-user needs.
Example: Testing documentation should include expected output details and actual output screenshots.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The initial phase of database development focuses on identifying user requirements and designing appropriate database structures. Entity-relationship diagrams serve as the foundation for database architecture.
Definition: Entity-relationship diagrams are graphical representations showing the relationships between different entities in a database system.
Vocabulary: Cardinality refers to the numerical relationship between entities .
Example: A Resort-Customer booking system demonstrates relationships between entities like Hotel, Resort, and Booking tables.
Highlight: Many-to-many relationships must be broken down into two one-to-many relationships for implementation in relational databases.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
7
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Master key SQL commands with this concise cheat sheet covering SELECT, INSERT, UPDATE, DELETE, and JOIN statements. Perfect for GCSE and National 5 revision, this resource provides clear examples and syntax to enhance your database query skills.
Computer ScienceExplore the fundamental concepts of Object-Oriented Programming (OOP) with this comprehensive guide. Covering key topics such as classes, objects, inheritance, encapsulation, polymorphism, and class diagrams, this resource is designed for AQA A-Level Computer Science students. Understand the principles of OOP and how to effectively apply them in programming.
Computer ScienceExplore essential Python programming constructs including variables, control structures, operators, and data types. This summary covers key definitions such as strings, arrays, and the differences between local and global variables, providing a solid foundation for understanding Python basics.
Computer ScienceExplore essential programming techniques including recursion, iteration, and modular programming. This summary covers key concepts such as algorithms, debugging, and data abstraction, providing a clear understanding of problem-solving methods in computer science. Ideal for OCR A-Level Computer Science students.
Computer ScienceExplore essential programming constructs including loops, conditionals, and object-oriented principles. This summary covers key concepts such as recursion, encapsulation, inheritance, and the differences between local and global variables. Ideal for OCR A Level Computer Science students preparing for Component 2.2.
Computer ScienceExplore key concepts of pseudocode including assignment statements, conditional statements, loops, and object-oriented programming. This summary covers essential programming constructs such as arrays, inheritance, and string handling, providing a comprehensive overview for students learning to write pseudocode effectively.
Computer ScienceApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
