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Computer Science ATAR U1 > Database Management Module > Flashcards

Database Management Module Flashcards

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1
Q

What is difference between data and information

A

Data:
- Raw, unprocessed facts
- Numbers, text, images

Information:
- Processed data that is meaningful
- Game scores, player statistics

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2
Q

What is difference between flat files and relational databases

A

Flat Files:
- Single table of data
- Simple, but inefficient with large data sets
- Eg. Spreadsheet listing all game players and their scores

Relational Databases:
- Multiple tables linked by relationships
- More efficient & scalable than flat files
- Eg. Tables for players, games, scores, linked by player ID

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3
Q

What is a Relational Database Management System (RDBMS)

A

Software that uses relational databases to store and manage data

Functions:
- Data storage, retrieval, updating
- Maintaining data integrity & security

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4
Q

What is the role of RDBMS in handling access to data

A

Access Control:
- Who can access & modify data
- Eg. Only game admins can change high scores

Data Retrieval:
- Efficient querying of data
- Eg. Retrieving top 10 scores from leaderboard

Transaction Management:
- Ensuring data consistency
- Eg. Saving game progress without losing data

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5
Q

What is the independence of data from RDBMS

A

Data can be modified / moved without changing applications using it

Benefits:
- Flexibility in data management

  • Easier upgrades & maintenance
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6
Q

What are entities

A

Objects / Things in real world with independent existence

Each entity has unique attributes

Eg. Students, Courses, Teachers, in a school database

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7
Q

What are attributes

A

Properties / Characteristics of entity

Define what data needs to be stored for each entity

Eg. Student entity attributes: StudentID, Name, DoB

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8
Q

What are relationships

A

Associations between entities

Eg. Relationship between Students, and Courses they enrol in

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9
Q

What are one-to-one relationships

A

Single record in one table, linked to single record in another table

Has constraints to ensure field in one table corresponds to only one field in another

Eg. Person and their passport

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10
Q

What are one-to-many relationships

A

Single record in one table, linked to multiple records in another table

Use foreign keys to link related records in different tables

Eg. Single teacher can teach multiple courses

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11
Q

What are many-to-many relationships

A

Multiple records in one table, linked to multiple records in another table

Use junction table to breakdown many-to-many into two one-to-many relationships

Eg. Students enrolling into multiple courses, each course has multiple students

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12
Q

What are tables

A

Collection of related data held in structured format within database

Implementation of entities

Has fields (Columns), and records (Rows)

Tables store data for entities

Ensured by primary & foreign keys, constraints

Field (Columns): Define type of data to be stored
- Eg. Student Table with fields; StudentID, Name, DoB, Email

Records (Rows): Each row is data entry for table

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13
Q

What is the hierachical structure of data

A

1) Field / Attribute:
- Smallest data unit
- Eg. StudentID in student table

2) Record:
- Single, complete set of fields
- Eg. Single student’s details

3) Table / Entity:
- Collection of related records
- Eg. Student table with all student records

4) Database:
- Collection of related tables
- Eg. School database with Students, Courses, Teachers tables

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14
Q

What are the different datatypes in databases

A

Integer:
- Whole numbers
- Eg. StudentID

Float:
- Decimal numbers
- Eg. GPA

Boolean:
- True / False values
- Eg. Enrollment Status

Text:
- Alphanumeric characters
- Eg. Student Address

Date:
- Date values
- Eg. Date of Birth

Choosing Data Types:
- Ensures data integrity & efficiency

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15
Q

What are primary keys

A

Uniquely identifies each record in a table

Contains unique values, cannot contain null values

Each record is unique, easily identifiable

Each table has 1 primary key

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16
Q

What are foreign keys

A

Links records between two tables

Establishes relationship between tables

Ensures referential integrity, foreign key value exists in referenced table

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17
Q

What are composite keys

A

Two or more columns used together as primary key

Useful when single column not unique enough to serve as primary key

Ensure combination of values in specified column is unique

Enhances data accuracy, prevents duplicate records with same combination of values

18
Q

What are insert anomalies in databases

A

Certain data cannot be inserted into database, without presence of other data

Incomplete data entry, causes need for unnecessary dummy data

Solution: Normalise database to separate related data to different tables

Example: Trying to add a new course without enrolling any student

19
Q

What are update anomalies in databases

A

Data requires multiple updates to avoid inconsistencies

Risk of data inconsistencies, increased maintenance effort

Solution: Normalise database to ensure each piece of data stored in only 1 place

Example: Updating a student’s address in multiple tables

20
Q

What are delete anomalies in databases

A

Deleting data removes additional data that should be retained

Loss of valuable data, difficulty maintaining historical records

Solution: Implement foreign key constraints to prevent accidental deletions

Example: Deleting a student removes record of their enrolments

21
Q

What is the purpose of data documentation for developers

A

Ensures Consistency: Provides clear & consistent reference for data structures, reducing errors & misunderstandings during development

Facilitates Maintenance: Helps developer understand database structure & relationship, easier to update / modify database in future

Supports Collaboration: Allows multiple developers to work on same project, shared understanding of database design & structure

Improves Troubleshooting: Helps identify & resolve issues related to data storage & retrieval efficiently

22
Q

What are data dictionaries

A

Detailed description of all data elements in database, including names, types, formats, relationships

23
Q

What are key components of data dictionaries

A

Table Names

Field Names

Data Types

Field Sizes

Constraints

24
Q

What is purpose of data dictionaries

A

Helps developers understand database structure

Ensure consistent use of data across application

25
Q

What are ER diagrams

A

ER diagrams use symbols & notation to represent entities, attributes, relationships in database

Uses “crow’s feet” symbols to indicate relationships (One-To-Many, Many-To-Many)

26
Q

What is purpose of ER diagrams

A

Provides clear & organised view of database structure, making it easier to design & understand relationships between entities

27
Q

How do you analyse ER diagrams when in Crow’s Foot Notation

A

Look for entities relevant to application

Ensure relationships correctly represented (Eg. One player has many scores, but each score only linked to one game)

All necessary attributes included, accurately represented for each entity

28
Q

How do you create accurate ER diagrams using Crow’s Foot Notation

A

Clearly define entities needed

Establish relationships between entities (Eg. One-To-One, One-To-Many)

Use crow’s foot symbols

Ensure diagram accurate reflects database structure

29
Q

How do you create a data dictionary

A

Document all fields

Include types, sizes, constraints, for each table

30
Q

What is resolving many to many relationships

A

Break down many-to-many relationships into two one-to-many relationships using junction tables

Unresolved M relationships lead to data redundancy and anomalies

Benefits:
- Ensures data integrity, simplifies database structure

31
Q

What is Currency in factors that influence integrity of data

A

How up-to-date the data is within the game

Ensures all game elements reflect the most current state

Outdated data leads to discrepancies, such as incorrect resource counts or character abilities

32
Q

What is Authenticity in factors that influence integrity of data

A

Data being used is genuine and trustworthy

Prevents cheating, maintains a fair playing environment

Use validation methods such as checksums or digital signatures

33
Q

What is Relevance of Data in factors that influence integrity of data

A

Only data that serves purpose within game is used

Irrelevant data clutters game processes, leads to slower performance and crashes

Consistently audit game data to ensure it remains relevant to gameplay mechanics

34
Q

What is Accuracy of Data in factors that influence integrity of data

A

Data correctly represents real-world or in-game values it’s supposed to

Accurate data crucial for balanced gameplay and fair outcomes

Inaccuracies lead to overpowered/underpowered elements within the game

35
Q

What is Handling Outliers and Cleaning Data in Game in factors that influence integrity of data

A

Outliers are data points that differ significantly from other data, potentially due to errors

  • Can distort game balance and player experience

Regularly check for and remove outliers / errors to maintain data integrity

36
Q

What is the relationship between validity and accuracy of data

A

Data validity ensure that data conforms to expected format and logic

Accuracy means data is correct, validity means data fits the required criteria

  • Data point can be valid but not accurate (Vice versa)

Implement validation checks, and accuracy tests, to ensure data is both valid and accurate

37
Q

What is the purpose of 3NFing

A

Eliminate data redundancy, ensure data consistency

Done by resolving Many to Many relationships

38
Q

How do you normalise to 1NF

A

Each table cell only contains atomic values, each record is unique, no repeating groups or arrays within column

Eg. Table with list of games that players own, each game in separate row

39
Q

How do you normalise to 2NF

A

Ensure all non-key attributes depend on entire primary key
- Separate into two tables

Eg. Each game in player’s library should be linked to a specific player, not just a general game list

40
Q

How do you normalise to 3NF

A

Remove attributes that do not directly depend on primary key
- Separate into two tables

Separate player information from game information

41
Q

What is the final result after 3NF

A

Tables organised into relations, minimal redundancy

Computer Science ATAR U1 (4 decks)

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