N5 Revision

​Keys

At N5 we work with relational databases - one which has two or more tables of related data. To uniquely identify every record in the database we create Primary Keys in each table. This should be something that can be unique for each record and not change over time. To link the tables together we create a Foreign Key. This is a primary key in its own table but used in another to link the data together. This allows us to search for data across the tables.

NOTE:
Each table has 1 primary key
Only 1 table will have a foreign key

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Keys

Query Design

This is normally asked for SELECT queries - when you are searching the database for something.

Legal Aspects of Databases

This is the only Law you need to know for N5 Computing. It's also known as UK GDPR
It covers personal / sensitive data held about individuals by organisations.
There are implications for both the individual and the organisation.

UK GDPR

UK General Data Protection Regulation (UK GDPR) that data must be:

• Organisation

• processed lawfully, fairly and in a transparent manner in relation to individuals, used for the declared purpose only, limited to the data needed for the declared purpose, accurate, not kept for longer than necessary, held securely

• Individuals

• Right to view data held, have it changed if wrong, compensation if inaccurate data caused harm / loss

Fixed Loops

We use a fixed loop when we know in advance how many times the code needs to repeat. We use a FOR loop.

for counter in range(5):
guess = input("What is your guess?")

Conditional Loops

We use a conditional loop when we do NOT know in advance how many times the code needs to repeat. We use a WHILE loop - it has a condition to make the loop run.

while password != "Let me in":
print("eh no!")
password = input("What is the password?")

Always look at the choice(s) given for answering: - pseudocode or programming language

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​Coding Questions